Design of Cr2O3@ZnO Hetero-junction Hierarchical Nanostructures with Enhanced Xylene-sensing Properties

Cr₂O₃@ZnO hetero-junction hierarchical nanostructures were designed to be enhanced xylene sensing material, and thereinto, flower-like ZnO hierarchical nanostructures were synthesized via a solution-based method, and then Cr₂O₃ particles were developed on the surface of ZnO petals via a solvothermal method. From the results of XRD patterns, SEM and TEM images, it can be observed that ZnO has a high-quallity crystallinity and Cr₂O₃ particles scatter uniformly on the suruface of ZnO. The products with different ratios of Cr₂O₃ were used to fabricate gas sensors, and the result indicates that the hetero-junction structures prompt the response to xylene, and the reason may be attributed to the decrease of main carriers concentration caused by the p-n junction between ZnO(n-type semiconductor) and Cr₂O₃(p-type semiconductor), as well as the catalytic oxidation effect on methyl groups of the xylene by Cr₂O₃.