Oxygen-defect rich SnO2-based homogenous composites for fast response and recovery hydrogen sensor

As a kind of green energy, hydrogen (H 2 ) has been widely concerned and applied by people. One of the biggest challenges for sensing applications is the quick detection of hydrogen leaks or their release in various conditions, particularly in large electric vehicle batteries. This study successfully constructed a quick response and recovery hydrogen sensor based on the In 2 O 3 -SnO 2 heterojunction. The response and recovery time of the In 2 O 3 -SnO 2 hydrogen sensor is 1.1/1.9 s to 50 ppm H 2 . This is reduced to 11.0 %/9.5 % compared to the SnO 2 hydrogen sensor. This sensor's remarkable gas detecting properties are mainly attributed to the In 2 O 3 -SnO 2 heterojunction creation, crystal structure modification, and increased specific surface area (92.9 m 2 /g). Homogenous In 2 O 3 -SnO 2 nanocomposites contain more oxygen defects, which is the primary factor enhancing the sensor's ability to detect gases. Firstly, indium ions are incorporated in the lattice of SnO 2 results in lattice distortion and enhances the presence of oxygen deficiency in the composites, which plays a pivotal role in achieving rapid response and recovery of the sensor. Secondly, In 2 O 3 -SnO 2 heterostructures promote rapid adsorption of oxygen molecules and target gases by facilitating effective electron mobility on their surface. The quicker response and recovery times of hydrogen sensors based on In 2 O 3 -SnO 2 heterojunctions are observed. This innovative approach to creating fast-responding gas sensors highlights the promise of heterojunction-based hydrogen sensors for real-time H 2 monitoring and opens up new research directions.