The preparation of Cr2O3@WO3 hierarchical nanostructures and their application in the detection of volatile organic compounds (VOCs)

Abstract

Cr₂O₃@WO₃ and WO₃ hierarchical nanostructures are prepared using a two-step water bath method, which just needs mild conditions and takes little time. The response to xylene of the Cr₂O₃@WO₃-based sensor is much higher (about 4 times) than that of a WO₃-based sensor, and both of the response and recovery processes are quick. As for the selectivity, the Cr₂O₃@WO₃-based sensor shows a better response to xylene, while the WO₃-based sensor shows a better response to ethanol. The reason for the response and selectivity change is considered to be that a heterostructure is formed between Cr₂O₃ (a P-type semiconductor) and WO₃ (an N-type semiconductor). Moreover, Cr₂O₃ is reported to show catalytic oxidation of methyl groups.