Strong Electronic Interaction Enables Enhanced Solar-Driven CO 2 Reduction into Selective CH 4 on SrTiO 3 with Photodeposited Pt 2+ Sites.

Targeting selective CO ₂ photoreduction into CH ₄ remains a challenge due to the sluggish reaction kinetics and poor hydrogenation ability of the unstable intermediate. Here, the active Pt ²⁺ sites were photodeposited on the SrTiO ₃ photocatalyst, which was well demonstrated to manipulate the CH ₄ product selectivity. The results showed that SrTiO ₃ mainly yielded the CO (6.98 μmol g ^-1 ) product with poor CH ₄ (0.17 μmol g ^-1 ). With the Pt ²⁺ modification, 100% CH ₄ selectivity could be obtained with an optimized yield rate of 8.07 μmol g ^-1 . The prominent enhancement resulted from the following roles: (1) the strong electronic interaction between the Pt ²⁺ cocatalyst and SrTiO ₃ could prompt efficient separation of the photoelectron-hole pairs. (2) The Pt ²⁺ sites were active to capture and activate inert CO ₂ into HCO ^3- and CO ₃ ^2- species and allowed fast *COOH formation with the lowered reaction barrier. (3) Compared with SrTiO ₃ , the formed *CO species could be captured tightly on the Pt ²⁺ cocatalyst surface for generating the *CH ₂ intermediate by the following electron-proton coupling reaction, thus leading to the CH ₄ product with 100% selectivity.