The influence of doping amount on the catalytic oxidation of formaldehyde by Mn-CeO2 mixed oxide catalyst: A combination of DFT and microkinetic study

Formaldehyde (HCHO) is a major environmental pollutant. The Mn-doped CeO2 catalyst has good catalytic performance for the oxidation of HCHO. The catalytic activity can be effectively tuned by changing the amount of metal doping. In this paper, density functional theory combined with micro-kinetic analysis are employed to provide a molecular level understanding to such effects. The CeO2(111) surface with different Mn doping content was used to study the oxidation mechanism of HCHO. Highly dispersed Mn doped ceria was dominant at low content of Mn. While with the increase of Mn doping, Mn begins to accumulate on the CeO2(111) surface. It is not conducive to the breaking of C-H bonds, the generation of oxygen vacancies and the adsorption of active oxygen species. Therefore, the low-content Mn-doped CeO2 catalyst has higher catalytic oxidation activity of HCHO. The present contribution is useful for further optimization of Mn-CeO2 catalysts towards HCHO oxidation.