Rutile RuO2 dispersion on rutile and anatase TiO2 supports: The effects of support crystalline phase structure on the dispersion behaviors of the supported metal oxides

In this study, to investigate the influence of support crystalline phase structure on the dispersion behaviors of the supported metal oxides, tetragonal rutile RuO2 supported on both tetragonal anatase a-TiO2 and tetragonal rutile r-TiO2 supports with different loadings have been prepared, characterized and probed by CO oxidation. It has been discovered that the monolayer dispersion capacity of RuO2 on r-TiO2 support is 0.84 mmol per 100 m(2) surface, which is much higher than 0.15 mmol per 100 m(2) surface on a-TiO2 support. Due to the close matching of the crystalline phase and lattice parameters between RuO2 and r-TiO2 , Ru-O-Ti interfacial bonds can be effectively formed, thus facilitating the RuO2 dispersion and resulting in a high monolayer dispersion capacity. On the contrary, the big difference of the crystalline phase and lattice parameters between RuO2 and a-TiO2 support impedes the formation of Ru-O-Ti interfacial bonds and Ru0 2 dispersion, resulting in a low monolayer dispersion capacity. As a result, RuO2 has a much stronger interaction with r-TiO2 than with a-TiO2 support, which can generate more abundant mobile oxygen sites. Therefore, in comparison with RuO2/a-TiO2 , the intrinsic activity of RuO2/r-TiO2 for CO oxidation is remarkably enhanced. On the basis of the results, it is rational to propose that a like-disperses-like phenomenon is present in the supported metal oxide systems.