The complete reaction mechanism of H<inf>2</inf>S desulfurization on an anatase TiO<inf>2</inf>(001) surface: A density functional theory investigation

Abstract

© 2017 The Royal Society of Chemistry. The complete reaction mechanism of H2S desulfurization on anatase TiO2(001) surface was elucidated using the plane-wave based density functional theory (DFT) method. The reaction starts from the dissociative adsorption of H2S on the TiO2surface. Subsequently, two competitive routes, H2O and H2formation, were investigated. The activation barriers for H2O formation range from 11 to 13 kcal mol-1, whereas those for H2formation are extremely high in the range of 67-87 kcal mol-1. On the basis of the activation energy barriers, the results indicate that the anatase TiO2(001) is very active for H2S desulfurization to produce H2O, resulting in S-substitution at the O2csites on the TiO2(001) surface. Electronic charge analyses indicate that S-doping onto the TiO2surface can enhance the photocatalytic activity of TiO2by reducing its band gap. In addition, by comparison with other metal oxide catalysts, such as TiO2(101), CeO2(111), CeO2(101), ZnO (1010) and α-Fe2O3(0001), we found that TiO2(001) is the most promising catalyst for H2S desulfurization.