Photo-enhanced thermal catalytic CO2 methanation activity and stability over oxygen-deficient Ru/TiO2 with exposed TiO2 {001} facets: Adjusting photogenerated electron behaviors by metal-support interactions

In this study, two Ru/TiO2 samples with different TiO2 facets were prepared to investigate their photo-thermal catalytic CO2 + H2 reaction behavior. Without UV irradiation, the 67% {001} facet (3RT) displayed improved thermal activity for methanation than that of 30% (0RT). After pretreatment, both exhibited enhanced activities, but H2-treated 3RT (3RT-H) superior 0RT (0RT-H). Under 3RT-H apparent photo-promoted and stability, was lower 0RT-H. Based on characterization results, it is proposed surface oxygen vacancies (Vos) (activating CO2) metallic Ru nanoparticles H2) mainly responsible methanation. For 0RT, pretreatment subsequent irradiation did not promote formation Vos, resulting in low activity. 3RT, one hand, promoted which regenerated under irradiation; other photogenerated electrons from transferred maintain nanoparticles. Both behaviors activation Moreover, holes favored dissociated H at migrating TiO2, also promoting These occurring may be attributed suitable metal-support interaction between {001}, easy lattice Vos. With reference analysis intermediates, a mechanism sample.