超分子组装在二维材料基室温甲醛传感材料中的应用

Application of supramolecular assembly in fabricating two-dimensional material based room-temperature formaldehyde sensing materials

甲醛作为室内空气中的主要挥发性有机化合物之一,对人体的健康产生了极大的威胁,因此对甲醛进行检测具有重要意义.传统的电阻式气体传感器一般基于低成本和高灵敏的金属氧化物,但其较高的操作温度和较低的选择性限制了它们的实际应用.开发高性能室温甲醛传感器迫在眉睫,其核心则是寻找性能优异的室温甲醛传感材料.二维材料由于具有独特的物理化学性质和电学性能,成为高性能室温甲醛传感器的热门候选材料.另一方面,超分子组装作为一种温和的材料修饰改性策略,也为大幅提高二维材料的室温甲醛传感性能提供了可能.本文整理了近年来基于二维材料的室温甲醛传感相关工作,总结了甲醛气体分子的传感机制,梳理了二维材料的分类与特性,归纳了用于室温甲醛传感的基于二维材料“主体”的超分子组装策略,并着重介绍了二维材料基超分子组装材料在电阻式室温甲醛传感中的应用,并对二维材料基室温甲醛传感材料的未来发展进行了展望.

Formaldehyde,as one of the major indoor volatile organic compounds,poses a great threat to human health,therefore,the detection of formaldehyde is of significant importance.Gas sensors are devices to detect specific organic vapors and hazardous gases,which can quantify gas concentrations and sensitively detect ultra-low concentrations of molecules,so they are well suited for formaldehyde detection.Conventional resistive gas sensors are generally based on low-cost and highly sensitive metal oxides,but the high operating temperature and low selectivity limit their practical application.The development of high-performance room-temperature formaldehyde sensors is urgent,the core of which is the search for excellent performance room-temperature formaldehyde sensing materials.Two-dimensional materials are popular candidates for high performance room-temperature formaldehyde sensors due to their unique physicochemical and electrical properties.The unique surface-to-volume ratio,electrical conductivity,optical transparency and mechanical flexibility of two-dimensional materials are expected to improve the performance of room-temperature formaldehyde sensors to a large extent.However,single two-dimensional materials usually have certain limitations in the sensing process,for example,the indiscriminate adsorption of gas molecules due to the huge specific surface and ultra-high reactivity,the long recovery time due to the gas molecules not easily desorbed from the material at room temperature,and the poor dispersion due to the molecular self-polymerization of two-dimensional materials,so the two-dimensional materials need to be regulated or modified to improve their formaldehyde sensing performance at room temperature.Covalent chemical modification can improve the sensing performance of two-dimensional materials,but the covalent bonds may disrupt the regular lattice structure of two-dimensional materials and affect the electrical properties of sensing materials.Supramolecular assembly,as a gentle material modification strategy,offers the possibility to significantly improve the room temperature formaldehyde sensing performance of two-dimensional materials.This review summarized the sensing mechanisms of formaldehyde gas molecules represented by surface adsorption oxygen ion and charge transfer.Then it sorted out the classification and properties of two-dimensional materials including graphene and its derivatives,transition metal disulfide,black phosphorus and MXene.Subsequently it summed up the supramolecular assembly strategy based on the"subject"of two-dimensional materials for room-temperature formaldehyde sensing,highlighted the application of two-dimensional material based supramolecular assembly materials for resistive room-temperature formaldehyde sensing.Finally,it prospected the future development of two-dimensional material based room temperature formaldehyde sensing materials.