Catalytic removal of formaldehyde at room temperature over supported gold catalysts

Abstract

Two kinds of Au/CeO2, prepared by deposition–precipitation (DP) using urea (U) or NaOH (N) as precipitants were investigated as catalysts for HCHO oxidation. H2-TPR and XPS techniques were used to characterize the Au/CeO2 samples. Due to the generation of increased amounts of active surface oxygen species resulting from the strong Au–CeO2 interaction, the Au/CeO2 (DPU) catalyst showed higher activity than the DPN catalyst, achieving 100% conversion of HCHO into CO2 and H2O at room temperature, even in the presence of water and at high GHSV (143,000h−1); moreover, the conversion was stable for at least 60h. The reaction mechanism and the rate limiting steps for HCHO oxidation over the Au/CeO2 catalysts were identified by means of in situ DRIFTS studies. The influence of oxygen and water on the formation and consumption of the formate reaction intermediates was also investigated. Results suggest that Au/CeO2 (DPU) is a promising catalyst for HCHO removal under real world conditions.