Enhanced photocatalytic CO2 reduction with defective TiO2 nanotubes modified by single-atom binary metal components

A binary component catalyst consists of single atoms (SAs– Pt and Au) anchored on self-doped TiO2 nanotubes (TNTs), was developed for photocatalytic CO2 reduction. The defects introduced TNTs substrate was stabilized with atomic Pt and Au via strong metal support interactions (MSI), due to which, the covalent interactions facilitated an effective transfer of photo-generated electrons from the defective sites to the SAs, and in turn an enhanced separation of electron–hole pairs and charge-carrier transmission. The Pt–Au/R-TNTs with 0.33 wt% of SA metals, exhibited a maximum of 149 times higher photocatalytic performance than unmodified R-TNT and a total apparent quantum yield (AQY) of 17.9%, in which the yield of CH4 and C2H6 reached to 360.0 and 28.8 μmol g−1 h−1, respectively. The metals loading shifted the oxidation path of H2O from •OH generation into O2 evolution, that inhibited the self-oxidization of the photocatalyst.