LAUSR

Abstract In this work, we investigated the mechanism of CO2 hydrogenation over the Pt-doped boron nitride nanosheets (Pt-BNNSs) by using the density functional theory (DFT). It is found that a Pt adatom can be effectively stabilized in boron vacancy site (Pt-BV). Our investigation shows that the reaction mechanisms of CO2 hydrogenation over Pt-BV can be found in three possible reaction pathways: (i) co-adsorption, (ii) H2 dissociation, and (iii) co-adsorption together with H2 dissociation pathways. The co-adsorption together with H2 dissociation provides the most favorable pathway among of these three proposed mechanisms. The important finding of our study is that the presence of CO2 in step of hydrogen dissociation plays an important role in producing the FA on the Pt-BV catalyst. Moreover, we found that the hydrogenation of CO2 via carboxylate (COOH) has the rate-determining step of 0.63 eV in the step of hydrogen dissociation. In addition, the microkinetic modelling suggests that the COOH route is found to be more energetically and kinetically feasible rather than that it is formate route (HCOO) with the reaction temperature at 350 K and pressure of 5 bar. Our calculation results provide an important information for developing Pt-BV catalysts and might shed light on experimental design the novel Pt-BV catalyst for the CO2 hydrogenation and the conversion of greenhouse gases into value-added products.