Applied Surface Science, Vol.484, 524-533, 2019
DFT simulations of dissociative chemisorption of sulfur-, nitrogen- and oxygen-containing molecules on mixed oxides with Mg, Al and Zn
In order to discuss the impact of the metal dopants insertion on the reactivity and catalytic activity of the MgO(001) surface in some important reaction mechanisms, ab initio calculations were performed to study the adsorption and dissociation reactions of the CH3CH2OH, CH3OCH3, CH3CH2SH, H2S, CH3SCH3 and N(CH3)(3) molecules on the MgO:Al(001) and MgO:Al,Zn(001) surfaces. The changes in the electronic and acid-basic properties were evaluated by Bader charge analysis and projected density of states (PDOS). The insertion of the dopants led to a decrease of the energy gap and an increase of the adsorption strength of the molecules on both surfaces compared to pure MgO. The rate constants and the activation energy at room temperature for dissociation reaction were also estimated. The results showed that both surfaces can be considered good catalysts for the dissociation of the H2S and CH3CH2SH molecules and the MgO:Al(001) surface demonstrated to be better catalyst than the MgO: Al, Zn(001) surface for the ethanol dissociation. On the other hand, MgO:Al(001) and MgO: Al, Zn(001) surfaces were not effective for the heterolytic break of the S/O/N-CH3 bonds.