Self-assembled hierarchical Au-loaded In2O3 hollow microspheres with superior ethanol sensing properties

Despite the significant advancement in preparing metal oxide hollow structures, most approaches rely on template-based multistep procedures for tailoring the interior structure. In this work, hierarchical self-assembled Au-loaded In2O3 hollow microspheres have been synthesized via a template-free hydrothermal method. The growth mechanism of this complex nanostructure was proposed based on the characterization results of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer-Emmett-Teller (BET) approach, TG-DSC analysis and X-ray photoelectron spectroscopy (XPS). With the large surface area, highly porous structure of the hierarchical and hollow architectures, and catalytic activity of Au nanoparticles, these unique hierarchical Au-loaded In2O3 hollow microspheres exhibit superior gas-sensing performances. The response value to 100 ppm ethanol is 185 at an operating temperature of 320 °C. It is expected this Au nanoparticles-functionalized hierarchically porous and hollow nanostructure may provide a new pathway to develop advanced nanomaterials for applications in gas sensors.