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.