Natures of (001) and (101) surfaces of original and MnO2-loaded anatase: A comparative study.

The (001) surface of TiO 2 is proved to be more active than the (101) surface in the SCR reaction while the roles of these two surfaces were still unclear. The present study carefully compared the adsorption characteristics of the (001) and (101) surfaces of original and MnO 2 -loaded anatase by density functional theory calculations. The oxidizing ability and the feasibility of the oxygen vacancy formation were further explored. It was found that NH 3 , NO, NO 2 and O 2 tended to adsorb on the (001) surface rather than on the (101) surface and the (001) surface was more oxidizing and was more prone to generate oxygen vacancies. Loading MnO 2 had a significant promotion on the performance of the (001) surface. The adsorption performance of the Mn(001) surface was much better than that of the Mn(101) surface. The limiting reactions for N 2 and H 2 O production on the Mn(001) and Mn(101) surfaces were both the dissociation process of NH 3. The energy barriers of the SCR reaction on the Mn(001) surface were smaller than that on the Mn(101) surface, indicating that N 2 and H 2 O formation on the Mn(001) surface was easier. Unlabelled Image • NH 3 , NO, NO 2 and O 2 tended to adsorb on the (001) face rather than on the (101) face. • The (001) face was more oxidizing and was more prone to generate oxygen vacancies. • Loading MnO 2 had a great promotion on the performance of the (001) face. • The energy barrier of N 2 and H 2 O formation on the Mn(001) face was low. [ABSTRACT FROM AUTHOR]