Theoretical Studies Of Methanol Synthesis By Hydrogenation Of CO₂ Over Cu（110） And CuZn（110） Catalysts’ Surface

Due to the wide application in areas of industry and environment,carbon dioxide hydrogenation to methanol by Cu/ZnO in Heterogeneous catalysis have attracted large number of studies.According to recent research,An analysis of the fitted parameters for a commerical Cu/ZnO/Al₂O₃ catalysis suggests that a more open Cu surface,for example,Cu（110）partically covered by oxygen,may provide a better model for the active of methanol synthesis.In this study,combined with the periodic density functional theory and the microscopic reaction kinetic model,We use the GGA-PAW exchange correlation potential and slab model,Adopt Cu Zn（110）/Cu（110）simulate Cu/ZnO alloy Catalyst surface.Theoretical study on the effect of Cu（110）surface alloying on the catalytic hydrogenation of CO₂ to methanol.The studies and obtained results are summarized as follows:First of all,we compared the adsorption properties of 22 reaction intermediates CuZn（110）and Cu（110）)in the hydrogenation of carbon dioxide to methanol.The most stable adsorption configurations,adsorption sites,adsorption enthalpy and entropy of the system were investigated.It was found that the effect of surface alloying on the stability of the intermediate products was different,but the adsorption of most intermediates was promoted.Then,the thermodynamic properties of the 48 elementary reactions of the reaction are calculated in detail.The reaction process is divided into four parts,which are the common elementary reactions,the HCOO channel elementary reactions,the HOCO channel elementary reactions and the CO channel elementary reactions.We contrast to explore the differences of elementary reaction in Cu（110）surface and CuZn（110）surface Thermodynamically.In all the elementary reactions investigated,the Cu（110）alloying promoted the reaction with the reaction of H₃CO*with the reaction of 24 to CO*,and the maximum effect was HCO*+H₂CO*→CO*+H₃CO*.The surface Zn atom has some inhibitory effect on some elementary reactions,but the degree is small.Finally,the possible HCOO mechanism and CO mechanism of the reaction of carbon dioxide hydrogenation to methanol were studied.Specifically,we investigate the activation energy and rate constant of Cu Zn（110）surface and Cu（110）surface related elementary reactions.Theoretical calculation of the surface,CO₂ hydrogenation in fact,mainly through the HCOO mechanism of methanol synthesis,CO by-product is completely decomposed by HOCO intermediates.The calculated TOF values show that the CuZn alloy formed on the catalyst surface has a significant promotion effect on methanol synthesis.