Density functional theory of transition metal oxide (FeO, CuO and MnO) adsorbed on TiO2 surface

Abstract

Titanium dioxide (TiO2) is widely used as a catalyst due to its high redox activity. To explore the metal oxide-TiO2 supported interactions and their effects, the electronic structure, adsorption energies and physical properties of different metal oxides (FeO, CuO and MnO) adsorbed anatase TiO2 (101) surface have been studied by means of density functional theory (DFT) calculations, compared with that on pure TiO2 surface. On the basis of the study, three different kinds of adsorption ratio among the metal oxides mentioned above (single metal oxide adsorption model, different metal oxide adsorption models with 2:2 ratio and 1:3 ratio), as a whole, 12 models were investigated to study the influence of different proportion of metal oxide adsorbed in the TiO2 carrier in order to find the best metal oxide adsorption ratio. The calculated results show that the different adsorption ratios of metal oxides have influences on the reactivity of catalysts. A small amount of CuO will increase the reactivity of the catalyst, but the overall catalytic effect of the catalyst containing CuO is not comparable to those only containing FeO or MnO. In terms of the structural stability of catalysts, the catalysts containing FeO are more stable than those only containing CuO and MnO, and the more FeO adsorption ratio, the more stable the catalyst structure will be. The results of binding energy and bandgap show that the structure of the 1:3 adsorption model is more stable than the other two models, and the mixed adsorption leads to the reduction of bandgap. The order of influence is 1:3 ratio adsorption model >2:2 ratio adsorption model > single metal oxide adsorption model.