In-situ construction of Au NPs decorated hierarchical In2O3/SnIn4S8 microcubes for enhanced trace NO2 sensing performance at room-temperature

A series of Au NPs decorated hierarchical In2O3/SnIn4S8 microcubes were prepared by in-situ growing SnIn4S8 nanosheets on the surface of In2O3 microcubes and followed by reducing Au NPs on the surface of the hierarchical composite. The gas sensing performance of the sensors based on the as-prepared materials were systematically assessed. And the results showed that coverage of SnIn4S8 and introduction of appropriate amount of Au NPs improved the gas sensing response of In2O3 toward NO2 at room temperature (RT). In particular, the sensor fabricated with 3 wt% Au NPs decorated In2O3/SnIn4S8 exhibited excellent selectivity (SNO2/Sother > 12.6), high response (155.65–7 ppm NO2), low theoretical limit of detection (LOD, 21.43 ppb), fast response/recovery time (132/191 s), good anti-interference performance, as well as repeatability and stability. The outstanding sensing performance at RT might be associated with a synergistic effect of heterostructures and the spillover effect of Au NPs, which could enlarge the electron depletion layer and promote the adsorption and dissociation of oxygen and nitrogen dioxide molecules. •Hierarchical In2O3/SnIn4S8 microcubes were prepared for NO2 sensing.•The In2O3/SnIn4S8-based gas sensor exhibited high response to trace NO2 at RT.•Au NPs decoration further improve the sensing performance of In2O3/SnIn4S8.•The excellent sensing properties of Au decorated In2O3/SnIn4S8 stems from the synergistic effect.