Hybrid Metal Oxide Nanocomposites for Gas-Sensing Applications: A Review

Nowadays, environmental pollution is a major concern due to toxic gases released by an increased number of vehicles, industries, and manufacturing plants worldwide. These toxic gases are the leading cause of severe health issues and environmental safety. There is an immediate need to develop cost-effective and efficient gas sensors to monitor the presence of toxic gases in our environment, so that preventive steps can be taken promptly to save human lives. Researchers have rigorously worked on this for the last three decades and have produced a diverse range of gas sensors that can detect even trace amounts of gases. The selection of an appropriate material is critical to design a gas sensor with excellent sensing properties. Different materials like 2D nanomaterials (graphene oxide, transition metals dichalcogenides (TMDCs), metal oxide semiconductors (MOX), organics, etc.) have been widely investigated by researchers to develop highly sensitive and selective sensors. This review is focused on the use of various hybrid and nanocomposite materials for the development of potential gas sensor devices and their applications. Different types of sensing mechanisms and effects of various parameters on the responses of gas sensors along with future promises of nanocomposite gas sensors are discussed in detail.