Highly sensitive and fast-response formaldehyde sensor based on In₂O₃/SnO₂ heterojunction

This research paper tackles the cross-sensitivity problem commonly encountered in metal oxide semiconductor gas sensors by suggesting a heterojunction structure to improve their overall gas-sensing performance. Pure-phase In₂O₃ nanocubes and In₂O₃/SnO₂ heterojunction composites were effectively synthesized via a one-pot hydrothermal method, and their sensing properties towards formaldehyde gas were systematically investigated. The experimental findings indicate that, in comparison with the pure In₂O₃ sensor, the In₂O₃/SnO₂ heterojunction sensor displays significantly higher response values to formaldehyde at the same operating temperature, along with more rapid response and recovery rates. Additionally, this heterojunction sensor demonstrates excellent selectivity for formaldehyde, retaining its high selectivity even in the presence of various interfering gases. This study offers a feasible approach for the development of highly sensitive, selective, and rapidly responsive formaldehyde gas sensors, and provides a valuable reference for the progress of gas sensor technology.