First-principles study on the mechanism of water-gas shift reaction on the Fe3O4 (111)-Fetet1

Abstract

Water-gas shift reaction (WGSR) is an important means for the production of H2 in industry, but the understanding of high-temperature WGSR on iron oxide catalysts is not sufficient, especially the relationship between crystal planes of Fe3O4 and reaction mechanisms and activity. In this paper, the three mechanisms of WGSR on Fe3O4 (111)-Fetet1 have been systematically studied by the density functional theory (DFT) considering spin polarization, and the whole reaction paths of three mechanisms were calculated in detail. The results indicate that association mechanism and regeneration mechanism are coexisted, and the effective energy barrier of the association mechanism is the lowest of 0.45 eV. For the step of H2 formation, the activity is affected by the coverage of surface *H and the O defects concentration. High surface H coverage and a lot of O defects are beneficial to the H2 formation. These results are helpful for further understanding the mechanism of WGSR on Fe3O4 catalyst.