Capacitive Toxic Gas Sensors Based on Oxide Composites: A Review

With the advancement of technology and our pursuit of better living standards resulted a concerning surge in pollutants from household, industry, automobile, and numerous other sources. There are many hazardous gases such as ammonia, nitrogen dioxide, sulfur dioxide, and volatile organic compounds which gets formed and dissipated mostly due to various human activity and sometimes naturally. Detection of all these toxic gases is essential for ensuring public health and safety. Oxide-based gas sensors have undergone significant development, exhibiting distinctive sensing properties, immense potential for diverse applications, and the ability to operate at room temperature. This article discusses the research and development of such harmful gas detection based on capacitive sensors that are composed of different metal oxides, metal oxide composites, and nanostructures. Study focuses on the sensing ability and performance of these sensors in terms of sensitivity, selectivity, and limit of detection. Furthermore, the mechanisms of gas sensing and their limitations in terms of improved stability, sensitivity, faster response, and ease of detection in ambient environments have been discussed. In addition, it provides an inclusive idea on future aspects of capacitive gas sensors and their potential applications in various fields.