Adensity functional theory study of water ga shift reaction on ZnO (1010) surface

Abstract

The carboxyl mechanism of the water gas shift reaction on the ZnO (1010) surface was initially investigated using the density functional theory (DFT) with the generalized gradient approximation–Perdew-Wang 1991 (GGA-PW91) to minimize the total energy and optimize the geometric structures. This overall carboxyl mechanism could be described mainly as follows: starting with the co- adsorption of CO and H2O leading to the H2O dissociation, COOH formed with the adsorbed CO and OH which then decomposed to CO2 endothermically by 0.38 eV with the barrier of 0.86 eV. The presence of decarboxylation was confirmed

under the pathway from cis-COOH to trans-COOH and then to CO2. The isomer transformation from cis to trans configurations was an endothermic reaction with 0.12 eV and the barrier of 0.73 eV. The optimized ZnO (1010) surface (4 x 2 x 1

as k-points) acquired the energy of -208.227 eV.

Keywords:

Density functional theory

Water gas shift