Formaldehyde is one of the most common and most serious contaminants in indoor air, which is harmful to human health. Catalytic oxidation, which can convert HCHO into CO2 and H2O in low temperature, have arose widely attention. Catalysts applied for low temperature HCHO catalytic oxidation are mainly supported noble metals. Among them, supported Au catalysts, especially Au/CeO2, exhibits excellently catalytic activity. So, we use the DFT calculations to investigate the HCHO oxidation mechanism on Au/CeO2 and make the role of Au in catalysts clear. Figure 1 shows the complete reaction pathway for HCHO oxidation on the AuCe1-xO2 (111) surface. The reaction mechanism consists of some significant steps, e.g. HCHO adsorption, two C-H bond cleavage, CO2 desorption, O2 adsorption, and H2O formation and desorption.Meanwhile, we also investigate the catalytic mechanism on the defective AuCe1-xO2-y (111) surface. The oxygen vacancy formation energy for AuCe1-xO2 (111) surface is much lower than the stoichiometric CeO2 (111) surface, so it’s important to research the mechanism. HCHO adsorbs on the AuCe1-xO2-y (111) surface, in which the oxygen atom fills the oxygen vacancy. After two-step C-H cleavages, CO forms, connected to Au on the ceria surface. Then, CO can easily desorb from the surface and then O2 adsorbs on the oxygen vacancy, or a co-adsorption of CO and O2 occurs. But the two different routes are under studying.

Formaldehyde oxidation mechanism on Au-doped CeO2: A DFT study

253rd National Meeting (2017)

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