Computational Studies Of HCHO Oxidation On MnO_x And CeO₂ Mixed Oxides

HCHO is one of the major environment pollutants.It will endanger human health and the atmospheric environment when the emission exceeds the standard.Mn-doped CeO₂ holds satisfactory catalytic performance toward HCHO oxidation.Studies have shown that changing the content of doping metal and morphologies can improve the catalytic performance of Ce-based catalyst.We adopt density functional theory combined with microkinetic analysis to study the mechanism of HCHO oxidation on different content of Mn doping CeO₂（111）surface and Mn doped CeO₂（110）surface.The effects of doping amount and different crystal planes are explored.The main research results are shown as follows.The influence of different content of Mn doping CeO₂ on HCHO oxidation are shown as follows.At lower content of Mn doping,Mn is well dispersed onto CeO₂（111）surface.At higher content of Mn doping,Mn O_x begins to gather on the surface,leading to negative catalytic activity.The higher content of Mn doping CeO₂（111）is unfavorable to C-H bond dissociation,the formation of oxygen vacancy and the adsorption and activation of O₂.Therefore,lower content of Mn doping CeO₂ holds the best catalytic performance.The influence of different content of Mn doping CeO₂ on HCHO oxidation are shown as follows.On the stoichiometric（110）and（111）surfaces,the activation barriers for C-H bond dissociation were different owing to the different HCHO adsorption models.On the defective surfaces,similar activation barriers on these two defective surface were observed due to the similar oxygen vacancy formation energy,HCHO adsorption models and the same adsorbed oxygen species.Therefore,the influence of surface termination on defective surface can be negligible.