Effect of preparation method on the performance of Pt-Au/TiO2 catalysts for the catalytic co-oxidation of HCHO and CO

A series of TiO2 supported Pt-Au bimetallic catalysts were prepared by impregnation, deposition-precipitation and impregnation-deposition-precipitation, and their catalytic activities for the co-oxidation of formaldehyde (HCHO) and carbon monoxide (CO) were evaluated at room temperature. The results show that the Pt-Au/TiO2 catalyst prepared via introducing Pt by impregnation and subsequently introducing Au by deposition-precipitation, exhibits excellent catalytic performance for the co-oxidation of HCHO and CO. The characterizations of the catalyst by means of Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Temperature Programmed Reduction (TPR) and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (in situ DRIFTS) revealed that the isolated Pt and Au sites are essential to the co-oxidation of HCHO and CO, because the HCHO oxidation occurring over Pt active sites while CO oxidation occurring over Au active sites can be conducted without mutual interference, thus simultaneously achieving both the high oxidation activity of HCHO and CO.