Exploring the Contribution of Intelligent Nanomaterials in Gas Sensing

Abstract

Gas sensors are crucial in various industries like chemicals, food processing, pharmaceuticals, health monitoring through breath analysis, as well as in household and environmental monitoring to ensure human safety. Chemo‐resistive gas sensors based on metal oxides convert gas information into electrical signals by interacting with adsorption and desorption processes. For metal oxide semiconductor gas sensors, sensitivity and selectivity enhancements are achieved through doping, functionalization, composite formations, heterojunction creation, and morphological adjustments. The formation of heterojunctions notably boosts the efficacy of the sensing material, leveraging synergistic effects to reinforce adsorption rates, catalytic activity acceleration, and the depletion interface for electrons and holes. Over the past few decades, nanomaterials have played a critical role in gas sensing applications. They have enabled the detection of a wide array of harmful and polluting gases, as well as volatile organic compounds serving as disease biomarkers. Additionally, incorporating heterostructure nanomaterials into heterojunctions significantly impacts sensing performance and detection speed. This review discussed various types of gas sensing devices, categorizing them based on the sensing elements employed, each possessing its own set of unique advantages and disadvantages. Nevertheless, the review underscored the importance of several key parameters and factors that influence the performance of gas sensors. Additionally, recent advancements in the utilization of nanomaterial composites for gas sensor applications, particularly in the detection of gases such as ammonia, hydrogen sulphide, and sulphur dioxide vapours, were discussed. Furthermore, the review highlights recent research endeavours and fundamental parameters, including sensitivity, detection limits, selectivity, response times, and recovery times.