Recent developments of nanomaterials-based conductive type methane sensors

Methane is an explosive gas in coalmines and needs to be monitored by methane sensors. Conductive-type methane sensors are small, simple and stable, and they are very promising for mining safety or home safety applications. They can even be employed in mining Internet of things if the power consumption can be lowered down to few milliwatts. Many researches of nanomaterials-based conductive-type methane sensors have been reported recently. This review intends to present a comprehensive and critical summary on the recent progresses in the nanomaterials-based conductive-type methane sensors field. Many excellent methane-sensitive nanomaterials will be present, such as SnO₂, ZnO, TiO₂, WO₃, carbon nanotubes, graphene, rare earth metal-based perovskite oxides and their hybrids. Particular attention is given to the synthetic methods of the nanomaterials, sensing mechanisms of the nanomaterials and the relationship between the sensing performance and the structures and components of the nanomaterials. Finally, the future trends and perspectives of nanomaterials-based conductive-type methane sensors are proposed.