Self-catalytic growth of hierarchical In₂O₃nanostructures on SnO₂nanowires and their CO sensing properties

Abstract

Brush-like hierarchical In2O3 nanostructures on SnO2 nanowires have been synthesized by a two-step thermal vapor transport process. To elucidate the growth mechanism, the structural evolution of hierarchical In2O3 nanostructures during the synthesis process was carefully examined. The experimental results showed that a self-catalytic vapor–liquid–solid (VLS) growth mechanism was responsible for the growth of hierarchical In2O3 nanostructures. Compared with the film counterparts, the hierarchical In2O3 nanostructures exhibited a higher sensitivity to low-concentration CO, which can be attributed to more active centers on the surface obtained from the enhanced oxygen vacancy defects and formation of bridging point contacts in the random network between the two electrodes.