Elucidating Ru Distribution State of Ru‐Promoted Pr2Sn2O7 Pyrochlore and its Effect on the Catalytic Performance for Toluene Deep Oxidation.

To obtain applicable catalysts for toluene combustion, Ru‐promoted Pr2Sn2O7 has been prepared with impregnation (Ru/Pr2Sn2O7) and hydrothermal method (Ru−Pr2Sn2O7). For the two Ru/Pr2Sn2O7 catalysts, Ru scatters on the surface of Pr2Sn2O7 as both metallic Ru and RuO2. In contrast, for the two Ru−Pr2Sn2O7 catalysts, Ru is substituted into Pr2Sn2O7 lattice as Ru4+. The distribution states of Ru affect significantly the active surface oxygen amount and the toluene adsorption capacity, which are the two major reasons influencing the reactivity. On Ru/Pr2Sn2O7, a greater quantity of active oxygen sites can be formed than on Ru−Pr2Sn2O7. Furthermore, the presence of surface Ru0 facilitates also toluene adsorption. As a consequence, the intrinsic activity of the two Ru/Pr2Sn2O7 catalysts are much higher than the two Ru−Pr2Sn2O7 catalysts. It is concluded that supporting Ru on Pr2Sn2O7 surface is a better way than doping Ru into its lattice to fabricate more active and applicable catalysts. [ABSTRACT FROM AUTHOR]