Pt–Au/CeO2 catalysts for the simultaneous removal of carbon monoxide and formaldehyde

Abstract

A series of Pt–Au/CeO₂ catalysts were prepared via the impregnation deposition–precipitation (IDP) and reduction–deposition precipitation (RDP) methods. The performances of the catalysts for the simultaneous removal of carbon monoxide (CO) and formaldehyde (HCHO) at room temperature were evaluated. The results show that the Pt–Au/CeO₂ catalyst, which was prepared via the RDP method, exhibited higher catalytic activity. The catalyst characterization results reveal that two factors accounted for this phenomenon. The first factor is that more negatively charged metallic Pt nanoparticles were obtained during the liquid phase NaBH₄ reduction treatment preparation process and the second factor is that more Au⁺ species were formed using urea as the precipitant in the Au deposition–precipitation. The larger number of negatively charged metallic Pt nanoparticles and Au⁺ species resulted in abundant chemisorbed oxygen, which contributed to the co-oxidation of HCHO and CO. In addition, water exhibited a negative effect on the simultaneous removal of CO and HCHO. Based upon these results, a possible mechanism for the simultaneous removal of CO and HCHO at room temperature is also proposed.