Hierarchical Au-Loaded WO₃ Hollow Microspheres With High Sensitive and Selective Properties to Toluene and Xylene

Functionalization of metal-oxide semiconductors by noble metal nanoparticles is one of the most efficient methods for enhancing the gas-sensing property of semiconducting sensors. Herein, we synthesized a series of Au-loaded hierarchical WO3hollow microspheres (Au-WO3) via a facile modified solvothermal method combining with wet impregnation method. The structure, elemental composition, and morphology of the synthesized materials were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscopy. The results show that the materials are uniform and independent WO3hollow microspheres, and Au nanoparticles are well distributed on the surface of WO3. The gas sensing properties of Au-WO3materials were investigated and the results suggest that Au loading could greatly improve gas sensing performance of WO3to aromatic compounds, especially toluene and xylene. Among the samples with different Au loading content, the one with 1.5 wt% Au (G3) exhibits the highest responses toward toluene and xylene at 340 °C. Moreover, the G3 sensor presents good responses, short response/recovery time, excellent selectivity, good reproducibility, and long-term stability to toluene and xylene. Excellent gas sensing properties of Au-WO3material make it a good candidate for detecting toluene and xylene.