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 WO
₃
hollow microspheres (Au-WO
₃
) 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 WO
₃
hollow microspheres, and Au nanoparticles are well distributed on the surface of WO
₃
. The gas sensing properties of Au-WO
₃
materials were investigated and the results suggest that Au loading could greatly improve gas sensing performance of WO
₃
to 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-WO
₃
material make it a good candidate for detecting toluene and xylene.