Hierarchical assembly of InO nanoparticles on ZnO hollow nanotubes using carbon fibers as templates: Enhanced photocatalytic and gas-sensing properties.

A novel hollow hierarchical nano-heterostructure consisting of ZnO nanorods coated with InO nanoparticles was prepared using a hydrothermal method combined with an annealing treatment via carbon fiber (CF) templates. Experimental results reveal that the InO/ZnO hierarchical composite has a tubular structure with an average diameter of ∼6μm and InO nanoparticles distribute uniformly on the ZnO nanorods. Significantly, the obtained heterostructure shows enhanced visible light photoactivity to methyl orange (MO) degradation and good selectivity and response toward ethanol even at a low detection limit (1ppm). This outstanding performance is a result of the one-dimensional tubular structure and the heterostructure formation between InO and ZnO, advantageous for the adsorption and diffusion and the separation of electrons and holes. In addition, the excellent performance is greatly improved by virtue of the evenly decorated InO nanoparticles on the ZnO nanorod surfaces, which provide more active sites for pollutants and gases.