Metal Oxide Ceramic Gas Sensors

Generally, ceramics are solid materials consisting of inorganic metal/metalloid/non-metal compounds with covalent/ionic bonds. Ceramics contain oxides, nitrides, and carbides and have considerable potential in different fields, including electronics, energy, chemistry, industry, and many more. In particular, the use of ceramic materials, especially metal oxides, as sensing elements to detect selectively detect toxic gases and volatile organic compounds (VOCs) has vastly increased in recent years. Particularly, semiconducting metal oxides (SMOs) based chemiresistive sensors are among the most popular for detecting various toxic gases and VOCs because of their high response, high stability, fast dynamics, and low costs. Typically, a chemiresistor is a material whose electrical resistance changes due to changes in the surrounding chemical environment. This review describes the fundamentals of SMOs-based chemiresistive sensors, the main characteristics of toxic gases and VOCs, and their gas detection mechanisms. In addition, the major challenges and the future significance of chemiresistive sensors are also outlined.