代谢修改参考后.docx

In the last two decades, Metal–Organic Frameworks (MOFs) have attracted extensive interest due to their well-defined crystalline nature, control over porosity, and variability in the chemistry of the metal nodes and organic linkers. These unique properties make MOFs suitable for use in gas sensing since they require both high sensitivity and selectivity. Cheng et al. (2022) note that the MOFs have surface areas exceeding 7000m²/g, which are much larger compared to zeolites and activated carbon.¹ The big surface area and evident pore size distribution, which can increase the contact area between the gas molecules and the sensing material, can increase the sensitivity.
在过去的二十年中，金属有机框架（MOF）由于其明确的结晶性质、对孔隙率的控制以及金属节点和有机连接体的化学变化而引起了广泛的兴趣。这些独特的特性使 MOF 适合用于气体传感，因为它们需要高灵敏度和选择性。程等人。 (2022) 指出，MOF 的表面积超过 7000 平方米/克，比沸石和活性炭大得多。 ¹比表面积大，孔径分布明显，可增加气体分子与传感材料的接触面积，提高灵敏度。

Additionally, the investigation by Chu et al. (2021) extends the notion that MOFs can be considered as molecular buildings blocks that could consist of any metal nodes and organic linkers, thereby providing an exact conception over the pore dimension and chemical ambiance of the MOFs.² This tractability makes it possible to synthesize and design MOFs for specific gas sensing applications, like toxic gases and volatile organic compounds (VOCs) among others. These authors posit that the possibility of tuning the composition of MOFs is one of the defining attributes of MOFs as porous materials.
此外，楚等人的调查。 (2021) 扩展了 MOF 可以被视为分子构件的概念，可以由任何金属节点和有机连接体组成，从而提供了 MOF 的孔隙尺寸和化学气氛的精确概念。 ²这种易处理性使得合成和设计用于特定气体传感应用的 MOF 成为可能，例如有毒气体和挥发性有机化合物 (VOC) 等。这些作者认为，调整 MOF 成分的可能性是 MOF 作为多孔材料的定义属性之一。

Nevertheless, some issues that may arise when implementing of MOFs are still unresolved. Thus, the stability of MOFs under practical application conditions and varying conditions such as humidity and temperatures are still an issue according to Najafi and Ghaemi (2024).³ They recommend that scientists should consider the synthesis of stronger MOFs that would retain their structures and functionalities in the long-term use. This realization further highlights the continued need to develop new strategies to synthesize MOFs and functionalize them.
然而，MOF实施过程中可能出现的一些问题仍未得到解决。因此，根据 Najafi 和Ghaemi （2024）的说法，MOF 在实际应用条件以及湿度和温度等变化条件下的稳定性仍然是一个问题。 ³他们建议科学家应考虑合成更强的 MOF，以便在长期使用中保留其结构和功能。这一认识进一步凸显了开发新策略来合成 MOF 并使其功能化的持续需要。

The growth of MOFs is well demonstrated by the fact that number of new MOF structures being synthesized and published each year has been increasing exponentially as depicted in the figure 1. This trend is an indication of the increasing application of MOFs in several fields of research, and this confirm its potential as a material in gas sensing.
每年合成和发表的新 MOF 结构的数量呈指数级增长，这一事实充分证明了 MOF 的发展，如图 1 所示。这一趋势表明 MOF 在多个研究领域的应用不断增加，这证实了其作为气体传感材料的潜力。

Figure 1. History of MOF Development (Cheng et al., 2022)
图1. MOF发展史（ Cheng et al., 2022）

1.2 Gas Sensor Development Technologies
1.2气体传感器开发技术

Gas sensors are vital in many operations as they serve as the environmental sentinel, safety in industries, and even in healthcare. There are basically three types of gas sensors: electro chemical, optical and chemiresistive sensors, each with their own strengths and weaknesses. For instance, electrochemical sensors provide high sensitivity, but have a short lifespan and instability according to Hodgkinson and Tatam (2013).⁴ Optical sensors are real-time that are highly specific to the material under investigation but are expensive.
气体传感器在许多操作中至关重要，因为它们充当环境哨兵、工业安全甚至医疗保健。气体传感器基本上分为三种类型：电化学传感器、光学传感器和化学电阻传感器，每种传感器都有自己的优点和缺点。例如，根据 Hodgkinson 和Tatam (2013) 的说法，电化学传感器具有高灵敏度，但寿命短且不稳定。 ⁴光学传感器是实时的，对所研究的材料具有高度特异性，但价格昂贵。

The chemiresistive sensor is an easier solution, and have the added advantage of high sensitivity at a comparatively lower cost. But they still lack selectivity and are sensitive to environmental changes, notably humidity. Neri (2015) offers a detailed history of chemiresistive sensors’ development over the last five decades with focus on the constant attempts to optimize their performance via material approaches.⁵
化学电阻传感器是一种更简单的解决方案，并且具有灵敏度高、成本相对较低的附加优势。但它们仍然缺乏选择性，并且对环境变化（尤其是湿度）敏感。 Neri (2015) 详细介绍了过去50 年化学电阻传感器的发展历史，重点关注通过材料方法优化其性能的不断尝试。 ⁵

In their work, Zhang et al. (2022) find that MOFs represent a highly favorable solution for the issues associated with chemiresistive sensors.⁶ Their work shows that chemiresistive sensors derived from MOFs, which include the functionalization of specific groups to improve gas adsorption, provide improved performance in terms of sensitivity and selectivity. For instance, amino group derived MOFs reveal a higher sensitivity to acidic gases such as CO₂ and NO₂.
在他们的工作中，张等人。 (2022) 发现 MOF 是解决与化学电阻传感器相关问题的非常有利的解决方案。 ⁶他们的工作表明，源自 MOF 的化学电阻传感器（包括特定基团的功能化以改善气体吸附）可在灵敏度和选择性方面提供改进的性能。例如，氨基衍生的 MOF 对 CO2 和 NO2 等酸性气体具有更高的敏感性。

In addition, utilizing conductive MOFs in chemiresistive sensors, Sharma et al. (2024) note an improvement of electrical conductivity by the sensors, which consequently increases the response rate and sensitivity of the devices.⁶ It helps remove one of the major drawbacks of conventional MOFs — low conductivity — while opening new prospects for creating effective gas sensors.
此外，Sharma 等人在化学电阻传感器中利用导电 MOF。 (2024)指出传感器的导电性得到改善，从而提高了设备的响应速度和灵敏度。 ⁶它有助于消除传统 MOF 的主要缺点之一——电导率低——同时为创建有效的气体传感器开辟了新的前景。

However, more issue is still unresolved to incorporate MOFs into the commercial gas sensor products. Sohrabi et al. (2023) outline challenges that research groups of MOF synthesis face, including the availability of composition and the reproducibility of sensing outcomes.⁷ For improving the stability and reducing the cost of the final product, they have suggested the idea of having MOFs composites/ hybrid structure with other conductive nanofillers like graphene.
然而，将 MOF 纳入商业气体传感器产品中还有更多问题尚未解决。索拉比等人。 (2023) 概述了 MOF 合成研究小组面临的挑战，包括成分的可用性和传感结果的可重复性。 ⁷为了提高最终产品的稳定性并降低成本，他们提出了与石墨烯等其他导电纳米填料形成 MOF 复合材料/混合结构的想法。

1.3 MOFs: The Potential for Gas Sensing
1.3 MOF：气体传感的潜力

The versatility in selectivity, multifarious synthesis, and large surface area of MOFs offer them as suitable candidates for gas sensing. Wei et al. (2023), have described and expounded on several types of MOF-based sensors to show that, the various functional groups and metal nodes can be tailored for various gases.⁸ For instance, MOFs having nodes of copper have displayed high selectivity for ammonia sensor, due to the affinity that exists between copper and nitrogen-based materials.
MOF 的选择性、多种合成方式和大表面积的多功能性使其成为气体传感的合适候选者。魏等人。 (2023)，描述和阐述了几种类型的基于 MOF 的传感器，表明不同的官能团和金属节点可以针对不同的气体进行定制。 ⁸例如，由于铜和氮基材料之间存在亲和力，具有铜节点的 MOF 对氨传感器表现出高选择性。

In Peng et al. (2023), the researchers discuss the application of coating devices with MOFs with a view of discovering low concentrations of dangerous gases in industries.⁹ Their study finds that MOF-coated sensors can have detection limits as low as 0.1 ppm for gases like hydrogen sulfide and methane. This level of sensitivity is rather important for safety in industrial contexts where high concentration of toxic gases is dangerous for health.
在彭等人。 (2023)，研究人员讨论了 MOF 涂层装置的应用，以期发现工业中低浓度的危险气体。 ⁹他们的研究发现，MOF 涂层传感器对于硫化氢和甲烷等气体的检测限可低至 0.1 ppm。这种灵敏度水平对于高浓度有毒气体对健康有害的工业环境中的安全性相当重要。

In their work published in 2022, Huang et al. investigate multi-gas sensing capability for which the same sensor is used to detect many gases. This capability is particularly useful in trip measurements, where at different points, the presence of diverse pollutants must be detected.¹⁰ According to authors, more efforts should be geared towards the synthesis of multi-functional MOFs, that will selectively capture various species of gases.
Huang 等人在 2022 年发表的作品中。研究使用同一传感器检测多种气体的多气体传感能力。此功能在行程测量中特别有用，因为必须在不同点检测不同污染物的存在。 ¹⁰作者认为，应加大力度合成多功能 MOF，以选择性地捕获各种气体。

The enhancement of MOF-based gas sensors is one of the most diligent paths which have been proposed and to some extent investigated. In Zhou et al. (2024), the authors describe the latest innovations in the synthesis conductive MOFs with improved charge transport characteristics, resulting in shorter response times.¹¹ It showed that their conductive MOFs can achieve a response time of less than 10 seconds for chemiresistive sensors, whereas conventional MOF-based sensors typically take much more time.
基于 MOF 的气体传感器的增强是已提出并在一定程度上进行研究的最努力的途径之一。在周等人中。 (2024)，作者描述了合成导电 MOF 的最新创新，具有改进的电荷传输特性，从而缩短了响应时间。 ¹¹结果表明，他们的导电 MOF 可以实现化学电阻传感器不到 10 秒的响应时间，而传统的基于 MOF 的传感器通常需要更长的时间。

However, there are some problems while having a practical use of MOF-based sensors. Yunusa (2014) explain that external conditions including temperature and humidity influence sensors in the same way.¹² To address these effects, they suggest the use of weathering films and encapsulation strategies, that will enhance the stability of MOF-based sensors in practical applications.
然而，基于MOF的传感器在实际使用中存在一些问题。 Yunusa (2014) 解释说，包括温度和湿度在内的外部条件也会以同样的方式影响传感器。 ¹²为了解决这些影响，他们建议使用耐候膜和封装策略，这将增强基于 MOF 的传感器在实际应用中的稳定性。

In conclusion, researchers have great potential to develop the MOFs for enhancing the gas sensing performance, but there are some questions to merit further investigation. Much of the work in the future should be targeted towards enhancing the stability, adaptability, and versatility of MOF based sensors. If these challenges are resolved adequately, using MOFs to design efficient and dependable gas sensors of the next generation becomes possible for the researchers.
总之，研究人员在开发 MOF 来增强气体传感性能方面具有巨大的潜力，但仍有一些问题值得进一步研究。未来的大部分工作应该致力于增强基于 MOF 的传感器的稳定性、适应性和多功能性。如果这些挑战得到充分解决，研究人员就可以使用 MOF 设计高效可靠的下一代气体传感器。

2. Principles and Performance Indicators of MOF-Based Gas Sensors
2 MOF基气体传感器原理及性能指标

2.1 Fundamental Working Principles of Chemiresistive Gas Sensors
2 .1化学电阻式气体传感器的基本工作原理

Chemiresistive gas sensors work through target gas interacting with gas-sensitive material, producing variation in surface conductivity. These include the oxidation or reduction reaction in which the adsorbed species either donate or accept electrons on the sensing material surface. By analyzing single-file diffusion in UTSA-280 membranes, Hsu et al (2024) postulated that control of the gas diffusion process by the sensor is key in the establishment of response time and sensitivity.¹³ They point out that in the cases of MOFs, the diffusion paths are narrow, meaning only single-file diffusion occurs with the gases, and thus improved selectivity and sensitivity to gases like CO₂.
化学电阻式气体传感器通过目标气体与气敏材料相互作用来工作，从而产生表面电导率的变化。这些包括氧化或还原反应，其中吸附的物质在传感材料表面上提供或接受电子。通过分析 UTSA-280 膜中的单列扩散，Hsu 等人 (2024) 推测传感器对气体扩散过程的控制是建立响应时间和灵敏度的关键。 ¹³他们指出，在 MOF 的情况下，扩散路径很窄，这意味着气体仅发生单线扩散，从而提高了对 CO2 等气体的选择性和灵敏度。

Figure 2. MOFs Gas Diffusion and Surface Reaction (Hsu et al., 2024)
图2. MOF气体扩散和表面反应（Hsu 等人，2024）

Yuan et al. (2022) also expand on the electron exchange process in the study mentioned below.¹⁴ In the case of chemiresitive materials when a reducing gas like hydrogen comes across its surface, it liberates or transfers electrons to the surface thus increasing its conductivity. On the other hand oxidizing gases like NO₂ take electrons, thus they reduce the conductivity. This reversible electron transfer mechanism forms the basis for the detection and quantification of gaseous species of interest.
袁等人。（2022）还在下面提到的研究中扩展了电子交换过程。 ¹⁴对于化学电阻材料，当氢气等还原气体穿过其表面时，它会释放电子或将电子转移到表面，从而增加其电导率。另一方面，像NO2 这样的氧化气体会吸收电子，从而降低电导率。这种可逆电子转移机制构成了感兴趣的气态物质的检测和定量的基础。

Besides, Nizamidin et al. (2021) practically focused on the development of Co-MOF optical waveguides for gas sensing applications.¹⁵ Based on the sensing mechanism, their results suggests that Co-MOF possesses excellent ammonia sensitivity because of the high coordination between cobalt and nitrogen. Such interaction allows for quick electron exchange, thus, the rate at which the sensor responds is improved. But the authors recall that it continues to be an issue to address the stability of such sensors under different conditions of environment.
此外，尼扎米丁等人。 (2021) 实际上专注于开发用于气体传感应用的 Co-MOF 光波导。 ¹⁵基于传感机制，他们的结果表明，由于钴和氮之间的高度配位，Co-MOF 具有优异的氨敏感性。这种相互作用允许快速的电子交换，从而提高了传感器的响应速度。但作者回忆说，解决此类传感器在不同环境条件下的稳定性仍然是一个问题。

2.2 Recognition of MOFs in Sensing Action of Gases
2.2 MOFs在气体传感作用中的识别

Within the gas sensing performance MOFs play a substantive role through the ways in which they are adsorptive. Such frameworks can accommodate gases either in a physical manner when the pore size of the material, its surface area and the functional groups involved are appropriate or chemically. Macarena et al. (2022) reviewed mixed-linker MOFs derived from HKUST-1 and discovered that varying the linkers affects the adsorption capacity and selectivity of the MOF.¹⁶ In detail, the study established that MOFs linked with hydrophilic groups have greater adsorption kinetics pertaining to polar gases such as water vapor and ammonia.
在气体传感性能中，MOF 通过吸附方式发挥着重要作用。当材料的孔径、表面积和所涉及的官能团合适时，这种框架可以以物理方式容纳气体，也可以以化学方式容纳气体。马卡雷纳等人。 (2022) 回顾了源自 HKUST-1 的混合连接体 MOF，发现改变连接体会影响 MOF 的吸附能力和选择性。 ¹⁶具体而言，该研究确定，与亲水基团连接的 MOF 对水蒸气和氨等极性气体具有更大的吸附动力学。

Figure 3. Adsorption Isotherm (He et al., 2012)
图3.吸附等温线（He et al., 2012）

Extensive information on the selective adsorption of small hydrocarbons using microporous MOFs was given by He et al., 2012.¹⁷ According to their findings, Cu₂(pzdc)₂(pyz) has a higher affinity for C₂H₂ than for CO₂ because the hydrogen bonding between the acetylene molecules and the oxygen atoms on the surface of MOF exists. Their adsorption isotherm shown (in the fig. 3) reveals that the C₂H₂ adsorption increases rapidly once the pressure is raised and reduce gradually at higher pressures, which stresses on the high selectivity of the MOF for C₂H₂.
He 等人于 2012 年提供了有关使用微孔 MOF 选择性吸附小分子碳氢化合物的大量信息。 ¹⁷根据他们的研究结果，Cu2( pzdc )2(pyz) 对 C2H2 的亲和力高于对 CO2 的亲和力，因为 Cu2(pzdc)2( pyz ) 对 C2H2 的亲和力高于 CO2，因为 Cu2(pzdc)2(pyz ) 对 C2H2 的亲和力高于 CO2，因为MOF表面存在乙炔分子和氧原子。它们的吸附等温线（如图3所示）表明，一旦压力升高，C2H2吸附量迅速增加，在较高压力下逐渐减少，这强调了MOF对C2H2的高选择性。

Wei and colleagues also investigated how functionalization could be utilized to improve MOF-based gas sensing in a work published in 2023.⁸ This study established that density of amino groups on the surface of MOFs has a direct impact on the selectivity of the gas molecules in question such as CO₂ and SO₂ which are acidic. This is due to the well-proven high affinity of the amino groups to interact with the gaseous species owing to their basicity nature. Furthermore, the present work showed that functionalized MOFs bear better response and recovery kinetics compared to non-functionalized MOFs.
Wei 及其同事还在 2023 年发表的一篇论文中研究了如何利用功能化来改进基于 MOF 的气体传感。8^这项研究表明，MOF 表面的氨基密度对气体分子的选择性有直接影响。 CO2 和 SO2 等酸性问题。这是由于氨基由于其碱性性质而与气态物质相互作用的亲和力已得到充分证明。此外，目前的工作表明，与非功能化 MOF 相比，功能化 MOF 具有更好的响应和恢复动力学。

2.3 Key Performance Indicators Analysis
2.3关键绩效指标分析

The measurement parameters that define the performance of a gas sensor hence the suitability of the gas sensor include the sensitivity level, the detectable limit, response time, and recovery time. In a recent review on MOF based sensors conducted by Gargiulo et al. (2022), the authors suggested that sensitivity can be improved by the MOF surface area and porosity.¹⁸ They used examples of MOFs with BET surface area greater than 5000 m²/g indicating that, they offer up to 30% improvement in sensitivity compared to conventional metal oxide sensors.
定义气体传感器性能以及气体传感器适用性的测量参数包括灵敏度水平、可检测极限、响应时间和恢复时间。 Gargiulo 等人最近对基于 MOF 的传感器进行了综述。 (2022)，作者提出可以通过 MOF 表面积和孔隙率来提高灵敏度。 ¹⁸他们使用 BET 表面积大于 5000 m²/g 的 MOF 示例，表明与传统金属氧化物传感器相比，它们的灵敏度提高了 30%。

Chen et al. (2021) aimed at the use of MOF-based sensors at low temperatures.¹⁹ In their investigation, they showed that some of the MOFs, including ZIF-8, can work in low temperatures as low as -20°C. The authors bring to this capability by low activation energy needed for gas adsorption on the MOF surface.
陈等人。 (2021) 旨在在低温下使用基于 MOF 的传感器。 ¹⁹在他们的研究中，他们表明一些 MOF，包括 ZIF-8，可以在低至 -20°C 的低温下工作。作者通过 MOF 表面气体吸附所需的低活化能实现了这种能力。

The response and recovery times are also factors important for the more real-world application of the gas sensors. Sohrabi et al. (2023) noted that the response time of MOF-based sensors are smaller than 10 seconds in general, depending on the type of gas and the structure of MOFs.⁷ Nevertheless, the time of recovery is more compared with the physical absorption because of a strong interaction between the gas molecules and the absorbing phase. To this, they recommend the adoption of application of dynamic desorption approaches for making desorption to be faster using thermal or UV stimulation.
响应和恢复时间对于气体传感器在现实世界中的应用也是重要的因素。索拉比等人。 (2023) 指出，基于 MOF 的传感器的响应时间通常小于 10 秒，具体取决于气体类型和 MOF 的结构。 ⁷然而，由于气体分子和吸收相之间存在强烈的相互作用，因此与物理吸收相比，恢复时间更长。为此，他们建议采用动态解吸方法，通过热或紫外线刺激使解吸更快。

However, there are some other aspects that are significant for MOF-based sensors, these include stability of the sensors at different conditions. MOF-based sensors’ performance can be influenced greatly by humidity levels, according to Yuan et al. (2022).¹⁴ To overcome this, they suggest employing hydrophobic coatings or including hydrophobic linkers in the structure of a MOF. From this approach, the effect of humidity has been minimized by a range of 40 percent which in turn provides reliability of the sensor when used in real life conditions.
然而，对于基于 MOF 的传感器来说，还有一些其他方面很重要，其中包括传感器在不同条件下的稳定性。 Yuan 等人表示，湿度水平对基于 MOF 的传感器的性能影响很大。（2022）。 ¹⁴为了克服这个问题，他们建议采用疏水涂层或在 MOF 结构中包含疏水连接体。通过这种方法，湿度的影响已最小化了 40%，这反过来又保证了传感器在现实生活条件下使用时的可靠性。

In conclusion, the utilization of MOFs for the fabrication of exotic gas sensors is highly beneficial for many reasons such as high surface area, tunable porosity and function. Literature surveyed in this section reveals that MOFs improve the sensitivity, selectivity, and response time of chemiresistive gas sensors. Although there has been considerable progress in the research, certain issues like, stability under the fluctuating environmental conditions and long recovery times are still not resolved satisfactorily. It is suggested that the following focuses should be explored in consequent studies, such as increasing the MOFs stability to combat these disadvantages, the integration of advanced desorption methods. If these challenges are kept in mind, there is a possibility to improve MOF based gas sensors for future use in industrial and environmental field.
总之，由于高表面积、可调孔隙率和功能等多种原因，利用 MOF 来制造奇异气体传感器是非常有益的。本节调查的文献表明，MOF 提高了化学电阻式气体传感器的灵敏度、选择性和响应时间。尽管研究取得了相当大的进展，但一些问题，如波动环境条件下的稳定性和恢复时间长等问题仍未得到令人满意的解决。建议在后续研究中应探索以下重点，例如提高MOFs的稳定性以克服这些缺点，先进解吸方法的整合。如果牢记这些挑战，就有可能改进基于 MOF 的气体传感器，以供未来在工业和环境领域的使用。

3. Synthesis Methods and Factors Influencing MOFs for Gas Sensing Applications
3. MOFs气体传感应用的合成方法和影响因素

3.1 Common Synthesis Methods of MOFs
3 .1 MOFs的常见合成方法

The process of combining Metal–Organic Frameworks (MOFs) is central in defining their characteristics of the structural framework, and their capability within a specific gas sensing application. Different synthetic approaches such as diffusion, solovothermal, mechanochemical, electrochemical, and microwave assisted technique have been reported to prepare MOFs with a high degree of crystallinity, porosity, and surface area.
金属有机框架 (MOF) 的组合过程对于定义其结构框架的特性及其在特定气体传感应用中的功能至关重要。据报道，不同的合成方法，如扩散、自热、机械化学、电化学和微波辅助技术，可制备具有高结晶度、孔隙率和表面积的 MOF。

Figure 4. Solvothermal Synthesis Process (Liu et al., 2023)
图4.溶剂热合成工艺（ Liu 等人，2023）

Liu et al. (2023) did a thorough study on how to achieve good MOF membranes’ crystallinity and film formation via in situ control.²⁰ They proved that the solvothermal synthesis process can be tuned to control the ratio of modulator to ligand, therefore the crystallinity of the MOF membranes is defect free with tremendous improvement in gas separation efficiency (Figure 4). This study pointed that the decrease in crystallinity is slightly beneficial to the flexible nature of the film, which in turn supports its mechanical integrity during gaseous separation. The optimal modulation strategy showed values of about 1.5 × 10⁶ GPU for CO₂ permeation, much higher than those determined for conventional MOF membranes.
刘等人。 (2023) 对如何通过原位控制实现良好的 MOF 膜结晶度和成膜进行了深入研究。20 他们证明，可以调整溶剂热合成过程来控制调节剂与配体的比例，从而控制 MOF 的结晶度膜无缺陷，气体分离效率大幅提高（图 4）。这项研究指出，结晶度的降低对薄膜的柔性性质略有有利，这反过来又支持其在气体分离过程中的机械完整性。最佳调制策略显示 CO2 渗透值约为 1.5 × 10⁶ GPU，远高于传统 MOF 膜确定的值。

Another broad class of synthesis techniques is the diffusion method, including solvent liquid diffusion, in particular. As pointed out by Wang et al., (2022)²¹, it is easy to carry out and yields well-defined MOF crystals with a similar particle size. Through a controlled solvent exchange operation, they were able to minimize the control of nucleation and growth actions, and therefore the MOFs possessed ordered pore structures. But the authors observed that the diffusion technique is only appropriate for the process, that requires a maximum of three layers and is very time consuming, hence it cannot be used for mass production.
另一大类合成技术是扩散法，特别包括溶剂液体扩散法。正如 Wang 等人( 2022) ²¹所指出的，该方法很容易进行，并且可以产生具有相似粒径的明确 MOF 晶体。通过受控的溶剂交换操作，他们能够最大限度地减少对成核和生长行为的控制，因此 MOF 具有有序的孔结构。但作者观察到，扩散技术仅适用于最多需要三层且非常耗时的工艺，因此无法用于大规模生产。

Further, Peng et al. (2023) studied the mechanochemical method for synthesizing MOFs, wherein metal salts and organic ligands are physically mixed and ground without using any solvent.⁹ This was revealed to be eco-compatible and reproducible method to synthesize MOFs with CPOs akin to those prepared using solvothermal techniques. However, a disadvantage with this method is that the particle size and surface morphology are not easily controlled, and these factors can affect the gas sensing efficiency.
此外，彭等人。 (2023)研究了合成MOF的机械化学方法，其中金属盐和有机配体在不使用任何溶剂的情况下物理混合和研磨。 ⁹这被证明是一种生态兼容且可重复的方法，可以用CPO合成 MOF，类似于使用溶剂热技术制备的方法。然而，这种方法的缺点是颗粒尺寸和表面形貌不易控制，这些因素会影响气敏效率。

3.2 Factors affecting synthesis of MOF
3 . 2 MOF合成的影响因素

Several factors affect the synthesis of MOFs, they include the metal ions and organic ligands employed, conditions under which the reaction is carried out and the use of modulators. Wang et al. (2023) also pointed out that in preference to dicarboxylates, high-valence metal-oxo clusters, for instance, Zr and Ti, afford MOFs of possessing superior thermal and chemical stability (Figure 5).²² In their work, they showed that Zr-MOFs are highly resistant to hydrolysis, and are highly recommended for use in highly humid conditions. It was observed that, the introduction of Ti-MOFs improved the photochemical properties of the sensors allowing tracking of reactive gases in an on-line fashion under the UV light.
有几个因素影响 MOF 的合成，包括所用的金属离子和有机配体、反应进行的条件以及调节剂的使用。王等人。 (2023)还指出，与二羧酸盐相比，高价金属氧簇，例如Zr和Ti ，使MOFs具有优异的热稳定性和化学稳定性（图5）。 ² ²在他们的工作中，他们表明 Zr-MOF 具有很强的耐水解性，强烈建议在高湿度条件下使用。据观察， Ti -MOF 的引入改善了传感器的光化学性质，允许在紫外光下以在线方式跟踪反应气体。

Figure 5. MOFs Chemical Stability (Wang et al., 2023)
图5. MOF 化学稳定性（Wang 等人，2023）

The organic ligands that are employed also dictate the size of pore and its functionality in the MOF. In MOFs for VOCs (volatile organic compounds) adsorption, Zhai et al. (2024) explored how ligands affect the capacity of MOFs.²³ They stated that MOFs prepared by hydrophobic ligands demonstrated higher selectivity to non-polar gases, and MOFs prepared by polar ligands gave better sensitivity to gases such as ammonia and water vapor.
所使用的有机配体还决定了 MOF 中孔的大小及其功能。在用于 VOC（挥发性有机化合物）吸附的 MOF 中，Zhai 等人。 (2024) 探讨了配体如何影响 MOF 的容量。23他们表示，由疏水性配体制备的 MOF 对非极性气体表现出更高的选择性，而由极性配体制备的 MOF 对氨和水蒸气等气体具有更好的敏感性。

Chen et al. (2021) also pointed out how reaction conditions such as temperature, pressure and solvent choice can affect the morphology and crystallinity of MOFs.²⁴ They also concluded that solvothermal reactions at high temperatures lead to MOFs with higher crystallinity and larger surface areas, and therefore are more suitable for gas sensing applications. But they said that such reaction conditions can be very sensitive, and may result to the formation of defects or cracks on MOFs affecting its performance.
陈等人。 (2021)还指出温度、压力和溶剂选择等反应条件如何影响MOF的形貌和结晶度。 ²⁴他们还得出结论，高温下的溶剂热反应会导致 MOF 具有更高的结晶度和更大的表面积，因此更适合气体传感应用。但他们表示，这种反应条件可能非常敏感，可能会导致 MOF 上形成缺陷或裂纹，影响其性能。

The other important parameter is the modulator which is capable of controlling nucleation and the growth of MOF crystals. Hajivand et al. (2024) analyzed the applicability of acidic modulators and their ability to manage particle size and homogeneity of MOF nanoparticles.²⁵ As per their findings, the size of particles reduces, and have better dispersal with raised concentration of the modulators Assistance with this sensors time and sensitivity. But using too many modulators can decrease crystal growth rate, which in turn leads to poor porosity of the structure and small adsorption of gases.
另一个重要参数是能够控制 MOF 晶体成核和生长的调制剂。哈吉万德等人。 (2024) 分析了酸性调节剂的适用性及其管理 MOF 纳米颗粒粒径和均匀性的能力。 ²⁵根据他们的研究结果，随着调节剂浓度的增加，颗粒的尺寸会减小，并且具有更好的分散性，有助于该传感器的时间和灵敏度。但使用过多的调制剂会降低晶体生长速率，进而导致结构孔隙率差和气体吸附量小。

3.3 Impact of Synthesis Methods on Gas Sensing Performance
3.3 合成方法对气敏性能的影响

The synthesis method and conditions play a major role in the structural features of the MOFs and as such the performance of the MOFs in terms of gas sensing. Zhang et al. (2021) have emphasized the fact that, MOFs showing high surface areas and well-defined pore dimensions show high sensitivity and low detection limits for various gases.²⁶ They were also able to give a comparison between MOFs synthesized by various technique. Solvothermal synthesized MOFs had a detection limit of 0.1 ppm of NO₂, while MOFs synthesized using mechanochemical methods have slightly higher limits of 0.5 ppm.
合成方法和条件对MOF的结构特征以及MOF在气敏方面的性能起着重要作用。张等人。 (2021) 强调了这样一个事实，即具有高表面积和明确孔径的 MOF 对各种气体表现出高灵敏度和低检测限。26 他们还能够对通过各种技术合成的 MOF 进行比较。溶剂热合成的 MOF 的 NO2 检测限为 0.1 ppm，而使用机械化学方法合成的 MOF 的检测限略高，为 0.5 ppm。

Wang et al., 2022 discussed that defect engineering is crucial in improving the gas sensing capabilities of MOFs.²¹ Introducing detects intentionally during synthesis further led to unsaturated metal site, these are series of sites that are active in adsorption of gases. They found that defect-engineered MOFs had 40% improvement in sensitivity for CO detection as compared to the pristine MOFs.
Wang 等人，2022 讨论了缺陷工程对于提高 MOF 的气体传感能力至关重要。 ²¹在合成过程中有意引入检测进一步导致不饱和金属位点，这些位点在气体吸附中具有活性。他们发现，与原始 MOF 相比，缺陷工程 MOF 的 CO 检测灵敏度提高了 40%。

Moreover, microwave-assisted synthesis was shown to decrease the response time of MOF-based sensors according in the work of Zhai et al. (2024). A drastic improvement was observed in the response times of the sensors.²³ According to his experiments, the sensors fabricated using this method took at most 5 seconds to respond to changes in the gas concentration, as compared to other methods of Synthesis that took 15 seconds. This improvement was attributed to the uniform heating and rapid nucleation provided by microwave irradiation, thus produces smaller and had a higher surface area.
此外，根据Zhai等人的工作，微波辅助合成被证明可以缩短基于 MOF 的传感器的响应时间。（2024）。传感器的响应时间得到了显着改善。 ²³根据他的实验，使用这种方法制造的传感器最多需要 5 秒才能响应气体浓度的变化，而其他合成方法需要 15 秒。这种改进归因于微波辐射提供的均匀加热和快速成核，从而产生更小且具有更高的表面积。

However, the challenges of synthesizing these materials include scaling up of the synthesis process and the ability to reproduce the process as desired. Liu et al. (2023) discussed that solvothermal and microwave assisted process gives MOFs with good quality, however, these methods cannot be scaled up since the reaction conditions have to be fine-tuned.²⁰ It also recommends that future studies should concentrate on designing continuous flow reactors for the large-scale synthesis of MOFs, which can improve the replicability of the product and lessen manufacturing expenses.
然而，合成这些材料的挑战包括扩大合成过程的规模以及根据需要重现该过程的能力。刘等人。 (2023) 讨论了溶剂热和微波辅助工艺可以使 MOF 具有良好的质量，但是，这些方法无法扩大规模，因为反应条件必须进行微调。 ²⁰它还建议未来的研究应集中于设计用于大规模合成 MOF 的连续流动反应器，这可以提高产品的可复制性并减少制造费用。

In conclusion, the synthesis methods and factors affecting the fabrication of MOFs are critical to the control of structural characteristics, and gas sensing capabilities of the developed MOFs. Research presented in this part of the work demonstrates the strengths and weaknesses of solvothermal, diffusion and mechanochemical syntheses. Reaction conditions and modulator selection play the most crucial role in determining the solvothermal synthesis of crystalline and porous MOFs with enhanced catalytic activity. However, issues of how MOFs are prepared at large scale or even for copying remain a matter of some concerns. They should direct their efforts to setup large scale synthesis strategies, as well as control of reaction parameters, to achieve synthesis of high quality MOFs with superior gas sensing properties. The solutions to these problems will lay the foundation for developing the MOF-based sensors for practical use in environmental monitoring and safety measures in industries.
总之，影响 MOF 制造的合成方法和因素对于控制所开发的 MOF 的结构特性和气敏能力至关重要。这部分工作中提出的研究展示了溶剂热合成、扩散合成和机械化学合成的优点和缺点。反应条件和调节剂的选择在决定溶剂热合成具有增强催化活性的结晶和多孔 MOF 方面起着最关键的作用。然而，如何大规模制备 MOF 甚至用于复制仍然是一些令人担忧的问题。他们应该致力于制定大规模合成策略以及反应参数的控制，以实现具有优异气敏性能的高质量MOF 的合成。这些问题的解决将为开发基于MOF的传感器在工业环境监测和安全措施中的实际应用奠定基础。

4. Applications and Challenges of MOFs in Gas Sensing
4. MOF在气体传感中的应用和挑战

4.1 Applications of MOFs in Gas Sensing for Different Gases
4 .1 MOFs在不同气体气体传感中的应用

Various gases have been detected by means of Metal–Organic Frameworks (MOFs) owing to their high porosity, a large surface area, and variability of functional sites. Of these, the detection of Volatile Organic Compounds (VOCs) has received a lot of concern they are environmentally and health hazardous. Another extensive study was conducted by Hajivand et al., (2024) on MOFs for VOC identification, which concluded that the MOFs containing hydrophobic functional groups have a high affinity for non-polar VOCs (Figure 6).²⁵ Their study shows that Zr-MOFs have exceptionally high adsorption properties for toluene where the adsorption rate reached 5.2 mmol/g at ambient temperature. This suggestion indicates that functionalization of MOFs with specific groups can improve selectivity and sensitivity towards VOCs, and therefore may be used for real-time air quality monitoring.
由于金属有机框架（MOF）的高孔隙率、大表面积和功能位点的可变性，可以通过金属有机框架（MOF）来检测各种气体。其中，挥发性有机化合物（VOC）的检测受到了很多关注，它们对环境和健康有害。 Hajivand等人 (2024) 对用于 VOC 识别的 MOF进行了另一项广泛研究，得出的结论是含有疏水性官能团的 MOF 对非极性 VOC 具有高亲和力（图 6）。 ²⁵他们的研究表明，Zr-MOF 对甲苯具有极高的吸附性能，在环境温度下吸附率达到 5.2 mmol/g。这一建议表明，具有特定基团的 MOF 的功能化可以提高对 VOC 的选择性和灵敏度，因此可用于实时空气质量监测。

Figure 6. detection of Volatile Organic Compounds (VOCs) (Hajivand et al.,2024)
图6. 挥发性有机化合物 (VOC) 的检测（ Hajivand等人，2024）

Besides VOC detection, MOFs also offer the possibility to selectively detect toxic gases, such as carbon monoxide (CO), ammonia (NH₃), and hydrogen sulfide (H₂S). In chemiresistive MOF-based sensors, Jo et al. (2023) studied the use of MOF sensors for detection of CO.²⁷ This work proved that Cu-MOFs are highly active and sensitive toward CO, owing to the most favorable interaction between CO and the Cu active sites that are unsaturated. The total response time of the system was determined as 8 sec while the system had a detection capability of 0.1 ppm. Likewise, Yang et al. (2022) also assessed the NH₃ sensors derived from Zn-MOFs and observed higher sensitivity, owing to the hydrogen bonding association of NH₃ with the framework bearing polar functional groups.²⁸
除了 VOC 检测之外，MOF 还可以选择性检测有毒气体，例如一氧化碳 (CO)、氨 (NH₃) 和硫化氢 (H2S)。在基于 MOF 的化学电阻传感器中，Jo 等人。 (2023) 研究了使用 MOF 传感器检测 CO。27^这项工作证明，由于 CO 和不饱和的 Cu 活性位点之间最有利的相互作用，Cu-MOF 对 CO 具有高度活性和敏感性。系统的总响应时间确定为 8 秒，而系统的检测能力为 0.1 ppm。同样，杨等人。 (2022) 还评估了源自 Zn-MOF 的 NH₃ 传感器，并观察到由于 NH₃ 与带有极性官能团的框架的氢键结合而具有更高的灵敏度。 ²⁸

In addition, Lv et al. (2023) proposed a new strategy by developing vertically enriched 2D MOFs for CH₄ and CO₂ detecting (Figure 7).²⁹ The vertical aligned structure has more active sites for the adsorption of the gas and hence enhanced the performance of the sensor. From the analysis of the result, the method also had a detection limit of 0.5 ppm for CH₄ and 1 ppm for CO₂, this showed that structural engineering could be used to improve gas sensing.
此外， Lv等人。 (2023) 提出了一种新策略，通过开发垂直富集的二维 MOF 来检测 CH4 和 CO2（图 7）。 ²⁹垂直排列的结构具有更多的气体吸附活性位点，从而增强了传感器的性能。从结果分析来看，该方法对CH4的检测限为0.5ppm，对CO2的检测限为1ppm，这表明结构工程可用于改善气体传感。

Figure 7. 2D MOFs for CH₄ and CO₂ detecting (Lv et al., 2023)
图7.用于 CH4 和 CO2 检测的 2D MOF（ Lv等人，2023）

4.2 Key Issues Related to MOF-Based Gas Sensors
4.2 与 MOF 气体传感器相关的关键问题

However, MOF based gas sensors have some issues, such as low conductivity, stability, and high fabrication cost etc. Initial studies on chemiresistive sensors using MOFs showed that one of the main drawbacks of conventional MOFs is their low electrical conductivity. The problem was solved by Lv et al. in another paper where they designed a triptycene assembled 2D MOF with improved conductivity. This worked confirmed that the introduction of conductive linkers augmented the response of sensor by 40% compared to normal MOFs.²⁹ However, these MOFs’ synthesis process is still challenging and takes considerable time to prepare required compounds, which acts as an impediment to large-scale synthesis of such structures.
然而，基于MOF的气体传感器存在一些问题，例如电导率低、稳定性差和制造成本高等。对使用MOF的化学电阻传感器的初步研究表明，传统MOF的主要缺点之一是其电导率低。 Lv等人解决了这个问题。在另一篇论文中，他们设计了一种三蝶烯组装的二维 MOF，具有更高的导电性。这项工作证实，与普通 MOF 相比，导电连接体的引入使传感器的响应提高了 40%。 ²⁹然而，这些 MOF 的合成过程仍然具有挑战性，需要相当长的时间来制备所需的化合物，这阻碍了此类结构的大规模合成。

Stability is another major challenge in the real-world applications of MOF based sensors. Some of the MOFs material degrades under high humidity and temperature conditions, thus world widening their performance and durability. Yusuf et al. (2022) surveyed remarkable stabilities and provided recommendations on how to prevent the hydrolysis of MOFs, the methods include: the incorporation of hydrophobic ligands and shell protection for MOFs.³⁰ According to their results, increasing the hydrophobicity of the polymer can enhance the stability of the supercapacitor by as much as fifty percent in a conditioned environment, however, this remains true only for short periods.
稳定性是MOF 传感器实际应用中的另一个主要挑战。一些MOF材料在高湿度和温度条件下会降解，从而在全球范围内提高其性能和耐用性。优素福等人。 (2022)调查了显着的稳定性，并就如何防止 MOF 水解提供了建议，方法包括：掺入疏水性配体和对 MOF 进行壳保护。 ³⁰根据他们的结果，增加聚合物的疏水性可以将超级电容器在调节环境中的稳定性提高多达百分之五十，但是，这仅在短时间内有效。

Other major issues include cost incurred in the synthesis of the MOF and the number of steps involved in the fabrication process. Al Obeidli et al. also reported challenges of using rare and expensive metal precursors including zirconium and titanium to enhance production costs.³⁰
其他主要问题包括 MOF 合成中产生的成本以及制造过程中涉及的步骤数量。阿尔·奥贝德利等人。还报告了使用锆和钛等稀有且昂贵的金属前体来提高生产成本的挑战。 ³⁰

The initiatives they suggested were that to use more accessible metals such as aluminium and iron for the synthesis, the move would potentially cut costs by a third, without negatively affecting the circuit’s scenario. However, the application of such methods has not been tested for scalability at industrial level.
他们建议的举措是，使用铝和铁等更容易获得的金属进行合成，此举可能会将成本削减三分之一，而不会对电路的情况产生负面影响。然而，此类方法的应用尚未经过工业级别的可扩展性测试。

4.3 Future Directions for MOF Development in Gas Sensing
4.3 MOF在气体传感领域的未来发展方向

Based on the mentioned above challenges, the future work on improving MOF-based gas sensors could be primarily on the synthesis of cost-effective, high-performance MOFs with high stability and selectivity. Another significant approach of interest is toward the development of new pathways of functionalization. Zhao et al. (2022) proposed that by modifying and introducing certain functional groups to MOFs, the selectivity of these materials for target gases can be adjusted.³¹ For instance, amino-functionalized MOFs obtained significantly improved sensitivity to CO2 and SO2, because of the high affinity between the amino groups and the acidic gases.
基于上述挑战，改进基于MOF的气体传感器的未来工作可能主要集中在合成具有高稳定性和选择性的经济高效、高性能MOF。另一个令人感兴趣的重要方法是开发新的功能化途径。赵等人。 (2022)提出，通过对MOFs进行改性和引入某些官能团，可以调节这些材料对目标气体的选择性。 ³¹例如，由于氨基与酸性气体之间的高亲和力，氨基功能化 MOF 对 CO2 和 SO2 的敏感性显着提高。

Another feasible area is the design of composite sensors based on the incorporation of MOFs with the nanomaterials. The performance of MOFs incorporated with GO was studied by Annamalai et al.(2022), and it revealed that the electrical conductivity as well as the response time of the sensor enhances with MOFs incorporation.³² Their hybrid sensor had detection and response time of 5seconds and, the LOD of 0.05ppm for NO₂, compared with MOF based sensors. As will be demonstrated later, this approach optimizes the properties of both materials to achieve improved performance measures.
另一个可行的领域是基于 MOF 与纳米材料结合的复合传感器的设计。 Annamalai等人（ 2022）研究了与 GO 结合的 MOF 的性能，结果表明，MOF 的结合增强了传感器的电导率和响应时间。 ³²与基于 MOF 的传感器相比，他们的混合传感器的检测和响应时间为 5 秒，NO2 的 LOD 为 0.05ppm。正如稍后将演示的，这种方法优化了两种材料的性能，以实现改进的性能指标。

Furthermore, another challenge is the lack of efficient large-scale synthesis procedures for MOFs, again a critical issue for creating sensor products based upon MOFs. In Głowniak et al. (2021), the authors presented mechanochemical synthesis as a more sustainable and easily scalable method, compared to solvothermal one.³³ It was their finding that MOFs synthesized by mechanochemical processes had comparable porosity and surface area, though cutting energy consumption by 60%. However, it can be advanced that there is a necessity for further optimization to approach the MOF synthesis on the level of reproducibility and quality.
此外，另一个挑战是缺乏有效的大规模 MOF 合成程序，这也是创建基于 MOF 的传感器产品的关键问题。在Głowniak等人中。 (2021)，作者提出，与溶剂热合成相比，机械化学合成是一种更可持续、更容易扩展的方法。 ³³他们发现，通过机械化学工艺合成的 MOF 具有相当的孔隙率和表面积，但能耗降低了 60%。然而，可以提出的是，有必要进一步优化 MOF 合成的重现性和质量水平。

Low-power gas sensing was proposed by Tang et al. (2022) by using room-temperature semiconductor-based MOFs.³⁴ Their work also emphasized that decreasing the operating temperature of MOF sensors also minimizes the energy consumption, and increases the lifetime of the sensors. The study showed that the sensors were 20% more durable when used at room temperatures than when operating at high temperatures.
低功耗气体传感由 Tang 等人提出。（2022）通过使用基于室温半导体的 MOF。 ³⁴他们的工作还强调，降低 MOF 传感器的工作温度还可以最大限度地减少能源消耗，并延长传感器的使用寿命。研究表明，传感器在室温下使用时比在高温下使用时耐用 20%。

To sum up, it has been demonstrated and pointed out that MOFs have a great potential for the gas sensing applications mainly relating to the detection of VOCs, toxic gases, and greenhouse gas, including carbon dioxide. Low conductivity, stability and high production cost are some of the problems that that hinder their usage, and hence needs to be sorted out. New developments in conductive MOFs, hybrid sensors, and eco-friendly synthesis appear to provide the solution to these difficulties. Further studies should be devoted to enhancement of functionalization techniques, combination of MOFs with fascinating nanomaterials and fabrication of efficient fabrication methods. These challenges have been addressed which allow enhancing the MOF-based gas sensors to fulfil the need of the industries, along with the environmental conditions monitoring.
综上所述，已经证明并指出MOF在气体传感应用方面具有巨大潜力，主要涉及VOC、有毒气体和温室气体（包括二氧化碳）的检测。低电导率、稳定性和高生产成本是阻碍其使用的一些问题，因此需要解决。导电 MOF、混合传感器和环保合成的新发展似乎为这些困难提供了解决方案。进一步的研究应致力于增强功能化技术、MOF 与迷人纳米材料的结合以及高效制造方法的制造。这些挑战已经得到解决，从而可以增强基于 MOF 的气体传感器以满足行业以及环境条件监测的需求。

5. Advantages of MOFs in Chemiresistive Gas Sensors
5. MOF在化学电阻式气体传感器中的优势

Among the various materials, the MOFs have attracted significant interest for developing the chemiresistive gas sensors, owing to the large surface area and pore volume, the flexibility in controlling the pore size, as well as the possibility of attaching chemical groups at the MOFs surface.
在各种材料中，MOFs由于具有大的表面积和孔体积、控制孔径的灵活性以及在MOFs表面附着化学基团的可能性，引起了开发化学电阻式气体传感器的极大兴趣。

In the study by Jo et al. (2023), MOF chemiresistive sensors are described in detail with specific emphasis on surface modification to improve sensor performance.²⁷ Functional groups incorporated to MOF structures and their effects on gas selectivity was the insight into of the study. The ability for amino-functionalized MOFs to enhance the sensitivity to nitrogen dioxide (NO₂) and Carbon dioxide (CO₂) gases was alternately and clearly shown by the authors. The response time for NO₂ detection was brought down to 8 sec and the detection of limit was made to be 0.1 ppm. These outcomes show that the net MOF sensor properties can be adjusted for specific application through surface functionalization. But Jo et al. (2023) also pointed out that while functionalization improved sensitivity by increasing surface area, as functionalization was increased further, it might also lead to pore accessibility issues and thus detract from sensitivity.²⁷
在乔等人的研究中。 (2023)，详细描述了 MOF 化学电阻传感器，特别强调表面改性以提高传感器性能。 ²⁷ MOF 结构中的官能团及其对气体选择性的影响是该研究的深入内容。作者交替清晰地展示了氨基功能化 MOF 增强对二氧化氮 (NO2) 和二氧化碳 (CO2) 气体敏感性的能力。 NO2检测的响应时间缩短至8秒，检测限度为0.1ppm。这些结果表明，MOF 传感器的净特性可以通过表面功能化来调整以适应特定的应用。但乔等人。 (2023)还指出，虽然功能化通过增加表面积提高了灵敏度，但随着功能化的进一步增加，它也可能导致孔隙可及性问题，从而降低灵敏度。 ²⁷

Yuan et al. (2022) was centered on the upregulation of the electrical conductivity of MOFs by the conversion of MOFs into conductive analogs. ¹⁴In their study, they proved that the MOFs transform under pyrolysis yielding Metal oxide or metal-carbon composites with enhanced electrical properties, compared with the original MOF with high surface area porosity. The authors presented that the sensitivity of the reaction towards NH₃ vapor by 35%, when employing a MOF-derived metal oxide composite compared to the selected MOF.
袁等人。 (2022) 的重点是通过将 MOF 转化为导电类似物来上调 MOF 的电导率。 ¹⁴在他们的研究中，他们证明，与具有高表面积孔隙率的原始 MOF 相比，MOF 在热解下发生转变，产生具有增强电性能的金属氧化物或金属-碳复合材料。作者提出，与选定的 MOF 相比，使用 MOF 衍生的金属氧化物复合材料时，对 NH₃ 蒸气的反应敏感性提高了 35%。

One of the most important parameters affecting gas sensors utilized in real conditions is stability. Chemiresistive sensors based on MOFs have been analyzed for stability over short and long durations by Yao et al. (2021), with focus on RH and temperature changes. ³⁵The authors identified that hydrophobic MOFs displayed better materials stability by showing more than 90% of their initial sensitivity to moisture, at the end of 30 days under high humidity. They noted however that not all these MOFs are stable and may require further changes to the surface or a protective coating, when used under extreme conditions.
影响实际条件下使用的气体传感器的最重要参数之一是稳定性。 Yao 等人分析了基于 MOF 的化学电阻传感器的短期和长期稳定性。（2021），重点关注相对湿度和温度变化。 ³⁵作者发现，在高湿度下 30 天后，疏水性 MOF 表现出更好的材料稳定性，对湿度的敏感性达到了 90% 以上。然而，他们指出，并非所有这些 MOF 都是稳定的，在极端条件下使用时可能需要进一步改变表面或保护涂层。

Majhi et al., (2022) in their recent review focused on MOFs with ultrahigh surface areas and their application in gas adsorption.³⁶ The authors also provided information on how MOFs with surface areas larger than 4000 m²/g could capture the gas molecules better, and had a higher sensitivity and response times. For instance, one Zn-MOF, used for H₂S detection, demonstrated response and recovery times of 5 and 10 seconds, respectively. According to Majhi et al. (2022), due to the unique porous characteristic of MOFs, interfacial gas diffusion, and adsorption, MOFs are recommended to be used as chemiresistive sensors.
Majhi 等人（2022）在最近的综述中重点关注了具有超高表面积的 MOF 及其在气体吸附中的应用。 ³⁶作者还提供了关于表面积大于 4000 m²/g 的 MOF 如何更好地捕获气体分子，并具有更高的灵敏度和响应时间的信息。例如，一种用于 H2S 检测的 Zn-MOF 的响应时间和恢复时间分别为 5 秒和 10 秒。根据 Majhi 等人的说法。 (2022)，由于MOFs独特的多孔特性、界面气体扩散和吸附，MOFs被推荐用作化学电阻传感器。

Small et al. (2021) first proposed the application of MOFs for destination irreversible gas sensing while focusing specifically on toxic gases.³⁷ Hence, their studies showed that several MOFs deform irreversibly after encountering toxic gases, that can cause life-threatening health problems in the long run. For example, MOF based sensing platform reported for irreversible sensing of Cl₂ displayed a marked and reversible change in color and conductivity. As Small et al. (2021) pointed out, although the above approach is suited for safety-critical applications, the reusability feature of such sensors is lacking, and hence the need to create sensor designs that can be reset or disposed of.
小等人。 (2021) 首次提出将 MOF 用于目标不可逆气体传感，同时特别关注有毒气体。 ³⁷因此，他们的研究表明，几种 MOF 在遇到有毒气体后会发生不可逆的变形，从长远来看可能会导致危及生命的健康问题。例如，据报道，基于 MOF 的传感平台可不可逆地传感 Cl2，显示出颜色和电导率的显着且可逆的变化。正如斯莫尔等人。 (2021)指出，虽然上述方法适合安全关键型应用，但此类传感器缺乏可重用性特征，因此需要创建可重置或处置的传感器设计。

Wei et al. (2023) also studied the effect of incorporating other types of conductive nanomaterials such as graphene and carbon nanotube with the MOFs.⁸ According to their research, they observed an improvement in the sensitivity as well as the response time of the sensors, a graphene-MOF composite sensor was able to identify 50 ppb of NO₂. For the response time, a value of 4 secs was achieved, which was relatively fast compared to MOF sensors that incorporated no metal. Wei et al. (2023) postulated that integration of conductive materials with MOFs overcomes the major drawback of MOFs, namely their low intrinsic conductivity, while taking advantage of high porosity required for gas adsorption.
魏等人。 (2023) 还研究了将其他类型的导电纳米材料（例如石墨烯和碳纳米管）与 MOF 结合的效果。 ⁸根据他们的研究，他们观察到传感器的灵敏度和响应时间都有所改善，石墨烯-MOF 复合传感器能够识别 50 ppb 的 NO2。响应时间达到了 4 秒，与不含金属的 MOF 传感器相比相对较快。魏等人。 (2023) 假设导电材料与 MOF 的集成克服了 MOF 的主要缺点，即其固有电导率低，同时利用了气体吸附所需的高孔隙率。

According to the study published by Garg et al. (2021), the authors highlighted the possibility of MOF synthesis for the large-scale fabrication of commercial gas sensors.³⁸ The authors pointed out mechanochemical and microwave-assisted synthesis methods as the two approaches that can be used to synthesize MOFs in large scale. In this case, bacterial cellulose nanocomposites were prepared for the purpose of gas sensing. And their study showed that mechanochemical synthesis MOFs maintained nearly the same porosity and gas sensing efficiency as solvothermally synthesized MOFs. But they noted that achieving uniform quality in large volumes is an issue, which they need to fine-tune through further process improvement.
根据 Garg 等人发表的研究。 (2021)，作者强调了 MOF 合成用于大规模制造商业气体传感器的可能性。 ³⁸作者指出机械化学和微波辅助合成方法是可用于大规模合成 MOF 的两种方法。在这种情况下，制备细菌纤维素纳米复合材料用于气体传感。他们的研究表明，机械化学合成 MOF 与溶剂热合成 MOF保持了几乎相同的孔隙率和气敏效率。但他们指出，大批量实现统一的质量是一个问题，他们需要通过进一步的流程改进来微调。

The collected studies reveal several advantages associated with the use of MOFs in chemiresistive gas sensors, which has been established in the before sections. First, the large surface area and pore volume of MOFs guarantee high gas adsorption capacity, which can improve sensitivity and response time. Jo et al., (2023) and Majhi et al. (2022) shows functionalization strategies for highly selective for some gases, and reduction of conductivity for MOFs by derivates and composites. However, as Garg et al. (2021) pointed out regarding the synthesis of MOFs, the scalability of these processes is also a way to achieving commercial production of the sensors, yet the quality variations present a challenge.
收集的研究揭示了在化学电阻气体传感器中使用 MOF 的几个优点，这些优点已在前面的章节中确立。首先，MOF 的大表面积和孔体积保证了高气体吸附能力，从而可以提高灵敏度和响应时间。 Jo 等人 (2023) 和 Majhi 等人。 (2022) 展示了对某些气体具有高选择性的功能化策略，以及通过衍生物和复合材料降低 MOF 的电导率。然而，正如 Garg 等人。 (2021)指出，关于MOF的合成，这些工艺的可扩展性也是实现传感器商业化生产的一种方式，但质量变化带来了挑战。

6. Conclusion
6 .结论

6.1 Future Directions for MOF Development in Gas Sensing
6 1 MOF在气体传感领域的未来发展方向

MOFs are a class of porous crystalline materials that have gained much attention for gas sensing applications because of their structural and functional features. Due to a large surface area, the possibility of controlling the pore size, and the ability to functionalize MOFs, they provide higher sensitivity and specificity to the target gases than conventional materials. Yuan et al. (2022) noted that functional groups on MOFs could selectively identify gases, thus, ammonia and hydrogen sulfide interact strong enough with functionalized sites of the MOF. Sohrabi et al. (2023) noted that the nature of MOFs to integrate assorted metal nodes and organic linkers offers multiple opportunities for developing gas sensors with unique application features.
M OF 是一类多孔晶体材料，因其结构和功能特征而在气体传感应用中受到广泛关注。由于表面积大、控制孔径的可能性以及 MOF 功能化的能力，它们比传统材料对目标气体具有更高的灵敏度和特异性。袁等人。 (2022)指出，MOF 上的官能团可以选择性地识别气体，因此，氨和硫化氢与 MOF 的官能化位点的相互作用足够强。索拉比等人。 (2023) 指出，MOF 集成各种金属节点和有机连接体的性质为开发具有独特应用功能的气体传感器提供了多种机会。

However, there are still several issues that need to be resolved in order to make the best use of MOFs in sensing applications as much as in other field applications. The authors mentioned the problem of stability in their work by Gargiulo et al., which detail that although MOFs demonstrate enhanced performance, they are less effective when exposed to high concentrations of humidity and temperature. This limitation greatly reduces their practical applications especially where raw industrial materials remain in use. Wei et al. (2023) confirmed this statement by describing the fact that some of MOF derivatives have a higher thermal and chemical stability, but, however, their preparation requires using very rigorous methods and consuming a lot of money.
然而，为了在传感应用中和在其他领域应用中一样充分利用 MOF ，仍然有几个问题需要解决。作者在 Gargiulo 等人的工作中提到了稳定性问题，其中详细说明了虽然 MOF 表现出增强的性能，但当暴露于高浓度的湿度和温度时，它们的效果较差。这种限制极大地降低了它们的实际应用，特别是在工业原材料仍在使用的情况下。魏等人。 (2023)通过描述一些MOF衍生物具有较高的热稳定性和化学稳定性的事实证实了这一说法，但它们的制备需要使用非常严格的方法并消耗大量资金。

There are two main challenges that affect the application of MOFs. First, the synthesis of MOFs is still relatively expensive despite the development of massive production techniques. Nizamidin et al. (2021) have shown that petal-like Co-MOF membranes synthesis for the respective application operates in several steps, during which the reaction conditions must be carefully regulated. Although the final sensors of this concept exhibit high sensitivity and short response times, the cost and difficulty of the synthesis method remains an issue for large scale production. Chen and colleagues also noted that although MOFs can work at low temperature, these sensor devices must be made cheaper to be widely applicable.
影响MOFs应用的主要挑战有两个。首先，尽管大规模生产技术得到了发展，MOF的合成仍然相对昂贵。尼扎米丁等人。 (2021) 表明，用于各自应用的花瓣状 Co-MOF 膜的合成分几个步骤进行，在此期间必须仔细调节反应条件。尽管该概念的最终传感器表现出高灵敏度和短响应时间，但合成方法的成本和难度仍然是大规模生产的问题。 Chen 及其同事还指出，虽然 MOF 可以在低温下工作，但这些传感器设备必须制造得更便宜才能广泛应用。

However, the repeat synthesis of these MOFs remains problematic as a challenge that demands further attention. Peng et al. (2023) indicated that these synthesis conditions yield inconsistent performance of the final device, therefore, standardization of the synthesis procedure of MOF-based sensors remains a challenge. To overcome this, Wang et al. (2022) proposed the use of innovative synthesis methods, such as the microwave assistance synthesis and the mechano synthesis, since they have attracted several interests in synthesizing high-quality MOFs with acceptable reproducibility.
然而，这些 MOF 的重复合成仍然是一个需要进一步关注的挑战。彭等人。 (2023) 指出，这些合成条件会导致最终器件的性能不一致，因此，基于 MOF 的传感器合成程序的标准化仍然是一个挑战。为了克服这个问题，Wang 等人。 (2022) 提出使用创新的合成方法，例如微波辅助合成和机械合成，因为它们在合成具有可接受的再现性的高质量 MOF方面引起了人们的兴趣。

6.2 Recommendations for Future Research
6 . 2对未来研究的建议

Based on the current state, it is necessary for the future research to direct more attention to expanding the highly effective functionalization paradigm and synthesizing new MOFs with higher sensitivity, selectivity, and stability for gas sensors. Another potential direction is the increasing of the selectivity of MOFs by modifying their structure with electron-donating EDGE or electron-withdrawing groups. Zhai et al. (2024) have also observed that the sensitivity of MOFs towards acidic gases, such as carbon dioxide and sulfur dioxide increased manifold, when the MOFs were functionalized with amino groups. The idea is that by varying the functional groups, it is possible to achieve very high selectivity in the sensors for a wide range of applications, such as environmental and process safety.
基于目前的状况，未来的研究有必要更多地关注扩展高效的功能化范式，合成具有更高灵敏度、选择性和稳定性的新型MOF用于气体传感器。另一个潜在的方向是通过用给电子 EDGE 或吸电子基团修改 MOF 的结构来提高 MOF 的选择性。翟等人。 (2024) 还观察到，当 MOF 被氨基官能化时，MOF 对酸性气体（例如二氧化碳和二氧化硫）的敏感性增加了数倍。这个想法是，通过改变功能组，可以在传感器中实现非常高的选择性，以适应环境和过程安全等广泛的应用。

The final research avenue that is worthy of future exploration relates to the use of other nanomaterials in the synthesis of MOFs-based composites. The effect of using MOF-graphene hybrid sensors was examined by Jo et al. (2023), their results indicated that the hybrid sensors had shorter response time and lower LOD values, because of the synergistic electrical conductivity from graphene. This approach does not only improve the sensing capability of the device but also solve the conductivity problem of the typical MOFs. According to Yang et al (2022), there is potential in discovering more functions in MOF-nanomaterial hybrid structures, that would create versatile sensing platforms for the detection of various gases.
最后值得未来探索的研究途径涉及在 MOF 基复合材料的合成中使用其他纳米材料。 Jo 等人检查了使用 MOF-石墨烯混合传感器的效果。 (2023)，他们的结果表明，由于石墨烯的协同导电性，混合传感器具有更短的响应时间和更低的 LOD 值。这种方法不仅提高了器件的传感能力，而且解决了典型MOF的导电问题。根据 Yang 等人 (2022) 的说法，MOF-纳米材料混合结构有可能发现更多功能，这将创建用于检测各种气体的多功能传感平台。

Besides the functionalization and hybrid approaches, the development of green and economical synthesis strategies are essential for the MOF-sensor application. To lower the cost Al Obeidli et al. (2022) suggested one green synthesis process by using low cost and easily available metal precusors like aluminum and iron. As part of their study, they found that green prepared MOFs are not different from those MOFs prepared using costly metals like zirconium and titanium. Meanwhile, Głowniak et al. (2021) supported the use especially of mechanochemical synthesis that does not require solvents and is relatively energy intensive.
除了功能化和混合方法外，开发绿色且经济的合成策略对于 MOF 传感器的应用也至关重要。为了降低成本 Al Obeidli等人。 (2022)提出了一种使用低成本且易于获得的金属前体（如铝和铁）的绿色合成工艺。作为研究的一部分，他们发现绿色制备的 MOF 与使用锆和钛等昂贵金属制备的 MOF 没有什么不同。与此同时， Głowniak等人。 (2021) 特别支持使用不需要溶剂且相对能源密集的机械化学合成。

Moreover, an important challenge of MOFs is the stability problems of the structures in severe conditions, which needs to be solved for to apply these materials. Zhao et al. (2022) suggested that further modifications of MOFs included use of protective coatings on the surface of MOFs or the use of hydrophobic functionalization of the ligands. Their studies showed that hydrophobic functionalized MOFs could have 40% higher stability under conditions of high humidity. It is noteworthy that developing such stable MOFs could enhance the usage of MOFs under environmental conditions, which are naturally uncontrolled in outdoor or/and industrial settings.
此外，MOFs的一个重要挑战是结构在恶劣条件下的稳定性问题，这是应用这些材料需要解决的问题。赵等人。 (2022) 提出对 MOF 的进一步修饰包括在 MOF 表面使用保护涂层或使用配体的疏水功能化。他们的研究表明，疏水性功能化 MOF 在高湿度条件下的稳定性可提高 40%。值得注意的是，开发这种稳定的 MOF 可以增强 MOF 在环境条件下的使用，而这些环境条件在室外或/和工业环境中自然是不受控制的。

Finally, the area of smart MOF-based sensors having live feedback and auto-repairing properties should be considered. According to Hajivand et al. (2024), the ability to incorporate stimuli-responsive elements into MOFs may help design sensors, that can self-repair after they have been saturated with the target gases. Such can help bridge existing gaps, that may hinder MOF development for use in sensors with long service life and high dependability.
最后，应考虑具有实时反馈和自动修复特性的基于 MOF 的智能传感器领域。根据哈吉万德等人的说法。 (2024)，将刺激响应元件纳入 MOF 的能力可能有助于设计传感器，这些传感器可以在被目标气体饱和后进行自我修复。这有助于弥补现有的差距，而这些差距可能会阻碍 MOF 开发用于长使用寿命和高可靠性的传感器。

In conclusion, the proposed MOFs are highly promising materials about the development of gas sensing technologies, as a result of their diverse structural characteristics and multifunctional capabilities. The use of MOFs in the construction of sensing platforms has been accompanied by improvements in their sensitivity, selectivity, response time, etc., but certain issues such as stability, reproducibility, and cost are still issues that need to be resolved. Coating these problems needs integration of functions and hybridization with nanomaterial and establish innovative green synthesis techniques.
总之，由于其多样化的结构特征和多功能性，所提出的 MOF 是气体传感技术发展中非常有前途的材料。 MOFs在传感平台构建中的使用伴随着其灵敏度、选择性、响应时间等方面的改进，但稳定性、再现性和成本等某些问题仍然是需要解决的问题。解决这些问题需要纳米材料的功能集成和杂化，并建立创新的绿色合成技术。

Subsequent studies should employ guided rationality in the synthesis of new MOFs with enhanced stability and low cost, for identified commercial and environmental uses. When combined with modern nanomaterials, MOFs can be used effectively as part of new-generation gas sensors, and the potential of smart sensing technology can be realized. Finally, the innovations in synthesis and application techniques will open the gates for the use of MOFs in different humanities such as environment, industry, health and safety.
后续研究应在合成具有增强稳定性和低成本的新型 MOF 时采用合理性指导，以用于确定的商业和环境用途。当与现代纳米材料结合时，MOF可以有效地用作新一代气体传感器的一部分，并可以发挥智能传感技术的潜力。最后，合成和应用技术的创新将为MOF在环境、工业、健康和安全等不同人文领域的应用打开大门。

Reflective Commentary
反思性评论

The choice of all the main papers for this literature review was made by the purpose of providing the unique advantages of metal-organic frameworks (MOFs) in chemiresistive gas sensors. First, an extensive database search returning articles that have been indexed for peer review was conducted, with focus on MOF-based sensing technologies. Some criteria for the selection of articles included specificity of the studies to chemiresistive mechanisms, the nature of the functionalization of MOFs, and the availability of experimental data with quantitative measurements. Studies conducted by Jo et al. (2023) and Yuan et al. (2022) were considered for their proper evaluation of MOF functionalization and increase in conductivity, which are fundamental to selectivity and sensitivity. Articles by Wei et al. (2023) and Majhi et al. (2022) were selected as the critical reviews of hybrid MOF composites and surface engineering techniques. Further, the works by Garg et al. (2021) and Yao et al. (2021) enriched the understanding of MOF synthesis scalability and stability concerns, which are important in the context of practical aspects of sensor deployment. Having Small et al. (2021) enabled the discussion of relatively recent ideas, such as irreversible gas sensing. This selection process helps to address both theoretical contributions as well as real-life applications of the materials, which formed a strong basis to assess MOF-based chemiresistive sensors.
本文献综述选择所有主要论文的目的是为了提供金属有机框架（MOF）在化学电阻式气体传感器中的独特优势。首先，进行了广泛的数据库搜索，返回已编入同行评审索引的文章，重点是基于 MOF 的传感技术。选择文章的一些标准包括化学抗性机制研究的特异性、MOF 功能化的性质以及定量测量实验数据的可用性。 Jo 等人进行的研究。（2023）和袁等人。 (2022) 因其对 MOF 功能化和电导率增加的正确评估而被认为是选择性和灵敏度的基础。魏等人的文章。（2023）和 Majhi 等人。 (2022) 被选为混合 MOF 复合材料和表面工程技术的关键评论。此外，Garg 等人的作品。（2021）和姚等人。 (2021) 丰富了对 MOF 合成可扩展性和稳定性问题的理解，这在传感器部署的实际方面非常重要。有小等人。（2021）促成了对相对较新的想法的讨论，例如不可逆气体传感。这一选择过程有助于解决材料的理论贡献和实际应用，为评估基于 MOF 的化学电阻传感器奠定了坚实的基础。

References:
参考：

Y. Cheng, S. J. Datta, S. Zhou, J. Jia, O. Shekhah and M. Eddaoudi, FMD3, Adv. Membr. Porous Mater. Center, 2022.
Y. Cheng、SJ Datta 、S. Zhou、J. Jia、O. Shekhah和 M. Eddaoudi ，FMD3，Adv。会员。多孔材料。中心，2022 年。

J. Chu, Y. Wang, F. Zhong, X. Feng, W. Chen, X. Ai, H. Yang and Y. Cao, EcoMat, 2021, 3, DOI: 10.1002/eom2.12133.
褚军，王勇，钟凤，冯晓，陈伟，艾晓，杨红，曹云， EcoMat ，2021, 3, DOI: 10.1002/eom2.12133。

P. Najafi and A. Ghaemi, Chem. Eng. J., 2024, 498, 128864.
P. Najafi 和 A. Ghaemi ，化学。工程师。杂志，2024, 498, 128864。

J. Hodgkinson and R. P. Tatam, Meas. Sci. Technol., 2013, 24, 052001.
J. Hodgkinson 和 RP Tatam ，Meas。科学。技术，2013，24，052001。

G. Neri, Chemosensors, 2015, 3, 1–13.
G. Neri ，化学传感器，2015, 3, 1–13。

R. Zhang, L. Lu, Y. Chang and M. Liu, J. Hazard. Mater., 2022, 429, 128321.
R.Zhang、L.Lu、Y.Chang 和 M.Liu、J.Hazard。硕士，2022, 429, 128321。

Sharma, S. B. Eadi, H. Noothalapati, M. Otyepka, H. D. Lee and K. Jayaramulu, Chem. Soc. Rev., 2024, 53, 2530–2577.
Sharma、SB Eadi 、H. Noothalapati 、M. Otyepka 、HD Lee 和 K. Jayaramulu ，化学。苏克。修订版，2024 年，53，2530–2577。

H. Sohrabi, S. Ghasemzadeh, Z. Ghoreishi, M. R. Majidi, Y. Yoon, N. Dizge and A. Khataee, Mater. Chem. Phys., 2023, 299, 127512.
H. Sohrabi 、S. Ghasemzadeh 、Z. Ghoreishi 、MR Majidi、Y. Yoon、N. Dizge和 A. Khataee 、Mater。化学。物理学，2023, 299, 127512。

H. Wei, H. Zhang, B. Song, K. Yuan, H. Xiao, Y. Cao and Q. Cao, Int. J. Environ. Res. Public Health, 2023, 20, 4388.
H.Wei，H.Zhang，B.Song，K.Yuan，H.Xiao，Y.Cao，Q.Cao，Int。 J.环境。资源。公共卫生，2023, 20, 4388。

X. Peng, X. Wu, M. Zhang and H. Yuan, ACS Sens., 2023, 8, 2471–2492.
X. Peng, X. Wu, M. Zhang 和 H. Yuan, ACS Sens., 2023, 8, 2471–2492。

X. Huang, Z. Gong and Y. Lv, TrAC, Trends Anal. Chem., 2022, 153, 116644.
X. Huang、Z. Kong和 Y. Lv ， TrAC ，趋势分析。化学, 2022, 153, 116644.

M. Zhou, Y. Li and G. Xu, TrAC, Trends Anal. Chem., 2024, 174, 116790.
M. Zhou、Y. Li和 G. Xu， TrAC ，趋势分析。化学, 2024, 174, 116790.

Z. Yunusa, M. N. Hamidon, A. Kaiser and Z. Awang, Sens. Transducers, 2014, 168, 61–75.
Z. Yunusa 、MN Hamidon 、A. Kaiser 和 Z. Awang，Sens. Transducers，2014, 168, 61–75。

C.-H. Hsu, C.-Y. Lin, P.-Y. Lin, C.-C. Chiu and D.-Y. Kang, SSRN, 2024, DOI: 10.2139/ssrn.4731910.
C.-H。许，C.-Y。林，P.-Y。林，C.-C。 Chiu和 D.-Y。康，SSRN，2024，DOI：10.2139/ssrn.4731910。

H. Yuan, N. Li, W. Fan, H. Cai and D. Zhao, Adv. Sci., 2022, 9, 2104374.
H. Yuan、N. Li、W. Fan、H. Cai和 D. Zhu， Adv 。科学，2022，9，2104374。

P. Nizamidin, A. Yimit, Y. Yan, B. Kutilike, N. Kari and G. Mamtimin, Sens. Actuators, B, 2021, 346, 130342.
P. Nizamidin 、A. Yimit 、Y. Yan 、B. Kutilike 、N. Kari和 G. Mamtimin ，Sens.执行器，B，2021, 346, 130342。

P.-R. Macarena, L.-C. Carlos and R. Ayala, J. Solid State Chem., 2022, 312, 123260.
P.-R。马卡雷纳，L.-C。卡洛斯和 R. 阿亚拉，《固态化学》杂志，2022, 312, 123260。

Y. He, W. Zhou, R. Krishna and B. Chen, Chem. Commun., 2012, 48, 349–368.
Y. He、W. Zhou、R. Krishna 和 B. Chen，化学。通讯，2012，48，349-368。

V. Gargiulo, M. Alfè, L. Giordano and S. Lettieri, Chemosensors, 2022, 10, 290.
V. Gargiulo、M. Alfè 、L. Giordano 和 S. Lettieri，化学传感器，2022, 10, 290。

X. Chen, R. Behboodian, D. Bagnall, M. Taheri and N. Nasiri, Chemosensors, 2021, 9, 316.
X. Chen、R. Behboodian 、D. Bagnall 、M. Taheri和 N. Nasiri ，化学传感器，2021, 9, 316。

Y. Liu, H. Chen, T. Li, Y. Ren, H. Wang, Z. Song, J. Li, Q. Zhao, J. Li and L. Li, Angew. Chem., Int. Ed., 2023, 62, e202309095.
Y. Liu 、H. Chen、T. Li、Y. Ren 、H. Wang 、Z. Song、J. Li、Q. Zhu、J. Li 和 L. Li, Angew 。化学，国际。编辑，2023 年，62，e202309095。

Z. Wang, Y. Wang, J. Yan, B. Liu, Y. Chen and Y. Tian, Mater. Adv., 2022, 3, 6728–6741.
Z. Wang、Y. Wang、J. Yan、B. Liu、Y. Chen 和 Y. Tian，Mater。高级，2022 年，3，6728–6741。

C. Wang, J. Yan, S. Chen and Y. Liu, ChemPlusChem, 2023, 88, e202200462.
C. Wang、J. Yan、S. Chen 和 Y. Liu， ChemPlusChem ，2023, 88, e202200462。

Y. Zhai, J. Ye, Y. Zhang, K. Zhang, E. Zhan, X. Zhang and Y. Yang, Chem. Eng. J., 2024, 149, 286.
翟Y. ，叶J. ，张Y.，张K.，詹E. ，张X.和Y.Yang，化学。工程师。 J.，2024, 149, 286。

Z. Chen, J. Wang and Y. Wang, Talanta, 2021, 235, 122745.
Z. Chen, J. Wang和 Y. Wang, Talanta , 2021, 235, 122745。

P. Hajivand, J. C. Jansen, E. Pardo, D. Armentano, T. F. Mastropietro and A. Azadmehr, Coord. Chem. Rev., 2024, 501, 215558.
P. Hajivand 、JC Jansen、E. Pardo、D. Armentano、TF Mastropietro 和 A. Azadmehr 、 Coord 。化学。修订版，2024, 501, 215558。

L. T. Zhang, Y. Zhou and S. T. Han, Angew. Chem., 2021, 133, 15320–15340.
LT 张，Y. Zhou和 ST Han， Angew 。化学, 2021, 133, 15320–15340。

Y. M. Jo, Y. K. Jo, J. H. Lee, H. W. Jang, I. S. Hwang and D. J. Yoo, Adv. Mater., 2023, 35, 2206842.
YM Jo、YK Jo、JH Lee、HW Jang、IS Hwang和 DJ Yoo ，Adv.硕士, 2023, 35, 2206842.

Y. Yang, X. Li, Y. Gu, H. Lin, B. Jie, Q. Zhang and X. Zhang, Surf. Interfaces, 2022, 28, 101649.
Y.杨，X.李，Y.顾，H.林，B.杰，Q.张和X.张，Surf。接口，2022, 28, 101649。

J. Lv, W. Li, J. Li, Z. Zhu, A. Dong, H. Lv, P. Li and B. Wang, Angew. Chem., Int. Ed., 2023, 62, e202217958.
J. Lv ，W. Li，J. Li，Z. Zhu，A. Dong，H. Lv ，P. Li 和 B. Wang ， Angew 。化学，国际。编辑，2023 年，62，e202217958。

V. F. Yusuf, N. I. Malek and S. K. Kailasa, ACS Omega, 2022, 7, 44507–44531.
VF Yusuf、NI Malek 和 SK Kailasa ，ACS Omega，2022 年，7，44507–44531。

Al Obeidli, H. B. Salah, M. Al Murisi and R. Sabouni, Int. J. Hydrogen Energy, 2022, 47, 2561–2593.
Al Obeidli 、HB Salah、M. Al Murisi和 R. Sabouni ，Int。 J.氢能源，2022，47，2561–2593。

Z. Zhao, H. Li, K. Zhao, L. Wang and X. Gao, Chem. Eng. J., 2022, 428, 131006.
Z.赵，H.李，K.赵，L.王和X.高，化学。工程师。 J., 2022, 428, 131006。

J. Annamalai, P. Murugan, D. Ganapathy, D. Nallaswamy, R. Atchudan, S. Arya, ... and A. K. Sundramoorthy, Chemosphere, 2022, 298, 134184.
J. Annamalai、P. Murugan 、D. Ganapathy、D. Nallaswamy 、R. Atchudan 、S. Arya，...和 AK Sundramoorthy ，Chemosphere，2022, 298, 134184。

S. Głowniak, B. Szczęśniak, J. Choma and M. Jaroniec, Mater. Today, 2021, 46, 109–124.
S. Głowniak、B. Szczęśniak、J. Choma 和 M. Jaroniec 、 Mater 。今天，2021 年，46，109–124。

Y. Tang, Y. Zhao and H. Liu, ACS Sens., 2022, 7, 3582–3597.
Y. Tang、Y. Zhu 和 H. Liu，ACS Sens.，2022, 7, 3582–3597。

M. S. Yao, W. H. Li and G. Xu, Coord. Chem. Rev., 2021, 426, 213479.
姚女士、WH Li和 G. Xu，Coord。化学。修订版，2021, 426, 213479。

S. M. Majhi, A. Ali, P. Rai, Y. E. Greish, A. Alzamly, S. G. Surya, ... and S. T. Mahmoud, Nanoscale Adv., 2022, 4, 697–732.
SM Majhi, A. Ali, P. Rai, YE Greish , A. Alzamly , SG Surya, ... 和 ST Mahmoud, 纳米尺度Adv., 2022, 4, 697–732。

L. J. Small, M. E. Schindelholz and T. M. Nenoff, Ind. Eng. Chem. Res., 2021, 60, 7998–8006.
LJ Small、ME Schindelholz和 TM Nenoff ，工业工程师。化学。研究，2021，60，7998–8006。

N. Garg, A. Deep and A. L. Sharma, Coord. Chem. Rev., 2021, 445, 214073.
N. Garg，A. Deep 和 AL Sharma，Coord。化学。修订版，2021 年，445，214073。