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 In 2 O 3 /SnIn 4 S 8 microcubes were prepared by in-situ growing SnIn 4 S 8 nanosheets on the surface of In 2 O 3 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 SnIn 4 S 8 and introduction of appropriate amount of Au NPs improved the gas sensing response of In 2 O 3 toward NO 2 at room temperature (RT). In particular, the sensor fabricated with 3 wt% Au NPs decorated In 2 O 3 /SnIn 4 S 8 exhibited excellent selectivity (S NO2 /S other > 12.6), high response (155.65–7 ppm NO 2 ), 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.