Improved Catalytic Performance of Au/α-Fe₂O₃-Like-Worm Catalyst for Low Temperature CO Oxidation

The gold catalysts supported on various morphologies of α-Fe₂O₃ in carbon monoxide (CO) oxidation reaction have been studied for many researchers. However, how to improve the catalytic activity and thermal stability for CO oxidation is still important. In this work, an unusual morphology of α-Fe₂O₃ was prepared by hydrothermal method and gold nanoparticles were supported using a deposition-precipitation method. Au/α-Fe₂O₃ catalyst exhibited great activity for CO oxidation. The crystal structure and microstructure images of α-Fe₂O₃ were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the size of gold nanoparticles was determined by transmission electron microscopy (TEM). X-ray photoelectron spectra (XPS) and Fourier transform infrared spectra (FTIR) results confirmed that the state of gold was metallic. The 1.86% Au/α-Fe₂O₃ catalyst calcined at 300 °C had the best catalytic performance for CO oxidation reaction and the mechanism for CO oxidation reaction was also discussed. It is highly likely that the small size of gold nanoparticle, oxygen vacancies and active sites played the decisive roles in CO oxidation reaction.