水热法制备三氧化钨的气敏响应研究进展(英文)

Studies on Principle,Expression and Characteristics of Gas Sensing Response of WO_3 Prepared by Hydrothermal Method

近年来,三氧化钨作为一种潜能材料在各种应用领域特别是在气敏传感器方面引起了广泛关注。综述了气敏响应的原理,灵敏度的灵活表示以及目前三氧化钨水热合成和气敏性研究的实验结果。三氧化钨的形貌和结构在很大程度上决定着其气敏性能。由于表面活性区域或体表比的增加能增强利于气体探测的一些性质,所以,晶粒的尺寸有待减小。在众多制备方法中,水热法可以用来制备出各种要求的形貌和结构,且尺寸较小。在水热处理过程中,添加一些辅助试剂还有助于调控三氧化钨的尺寸大小,表面形貌、形状和晶体结构等。大多数关于气体探测的工作都是致力于提高三氧化钨的灵敏度,实现对低浓度气体的探测,扩大探测的气体种类等。事实上,通过优化制备方法,掺杂以及电极的设计等在这些方面都已经取得了很大的成功。但是,得到的这些三氧化钨基气体传感器通常仅能在高于150℃的工作温度下才能发挥出较好的气敏性能。三氧化钨基气体传感器未来研究方向:一方面,寻求新的掺杂材料,使用某些辅助试剂,准确控制制备条件来优化三氧化钨的气敏特性将是人们广泛采用的途径;另一方面,改变探测气体的方式(不测试三氧化钨电学性质的变化),通过记录三氧化钨基传感器光学性质的变化来分析器气敏响应。

WO3 has gained considerable interest recently as a promising material for a variety of applications, especially in gas sensor field. This article provides a review of the principle and expression of gas sensing response as well as the cur- rent experimental efforts on the hydrothermal synthesis and gas sensing characteristics of WOa. The morphologies and structures of WO3 determine the gas sensing characteristics to a large extent. Because the increase of active surface area or surface-to-volume ratio would enhance the properties for detecting gases, small sizes of grains need to be decreased. A- mong the numerous preparation methods, hydrothermal synthesis is easily used to grow various desired morphologies and structures with small sizes. Adding some assisting agents helps to tune the size, surface morphology, shape and crystal- line structure of WO3 in the hydrothermal process. Most of work on gas detection has been devoted to the improvement of sensitivity, detecting low concentration target gas and the increase of gas types. In fact, well advancements have been gained in these aspects by optimizing the grow method, dopant, electrode and so on. However, these WO3-based gas sensor just usually performed well above 150 ℃. Therefore, this paper also points out some trends for future investiga- tion. Seeking new dopant material, controlling the preparation conditions accurately and making use of the very assisting agents to optimize the gas sensing characteristics of WOa are the widely approaches. Additionally, change the manner to detect the gases, such as recording the change of optical properties of WOa-based sensor instead of the electrical properties.