Recent advances in multifunctional materials for gas sensing applications

The problem of air pollution and an increasing number of hazardous gases leaking into the atmosphere is of growing concern. To protect human and animal life it is necessary to monitor these toxic gases. Gases such as NH3, CO2, CH4, CO, and SO2 can lead to fatal health risks. Gas sensors have attracted extensive attention from academic and commercial fields to monitor such pollutants. The sensing properties, such as measurement sensitivity, response and recovery time, and selectivity, heavily rely on sensing. In this review, the different groups of the sensing materials are described in detail, including metal oxides, metal sulfides, metal ferrites, perovskites, carbon materials, organic polymers, transition metal dichalcogenides, and chalcogenide nanomaterials. The synthesis methods of these compounds and their basic properties are elaborated. Also, morphology has a very important role to tailor the performance of gas sensors. In addition, this review discusses the gas sensing properties of the aforementioned materials along with the explanation of their sensing mechanisms. Special attention is paid to the detection of hazardous organic vapors and toxic gases. The wide discussion of various materials-based gas sensors in near future can be attached to the Internet of Things to develop more rigid and highly sensitive gas leakage detectors to avoid accident risks as well as health threats. This review provides a comprehensive overview of the recent achievements in the application of sensors for different gas detection and indicates the current challenges and future outlooks in this field.