Chemiresistive Gas Sensors Based on Hollow Heterojunction: A Review

Abstract Chemiresistive gas sensors are widely used in tens of thousands of applications, from health and safety to energy efficiency and emission control. Fabrication of highly effective sensing materials is of great significance for the practical applications in efficient gas detection. Among numerous sensing materials, semiconductor‐based sensing materials with hollow and heterojunction structures demonstrate distinct advantages such as high sensitivity, low operating temperature, and fast response/recovery. In this paper, the mechanism of gas sensing by chemiresistive sensors, as well as the mechanisms responsible for enhanced sensing performance in hollow structure and heterojunction are reviewed. Both single‐shelled and multi‐shelled hollow heterojunction materials applied in gas detection are presented. Then, the design and application of open hollow heterojunction in gas sensing are discussed. This review provides a deeper understanding of innovative works on the material design of high‐performance sensing materials for gas detection. It also summarizes the key technical challenges in material development and points out the perspectives for future studies on the next generating of chemiresistive gas sensing materials.