Co-Dissolved Isostructural Polyoxovanadates to Construct Single-Atom-Site Catalysts for Efficient CO 2 Photoreduction.

We explored a co-dissolved strategy to embed mono-dispersed Pt center into V ₂ O ₅ support via dissolving [PtV ₉ O ₂₈ ] ^7- into [V ₁₀ O ₂₈ ] ^6- aqueous solution. The uniform dispersion of [PtV ₉ O ₂₈ ] ^7- in [V ₁₀ O ₂₈ ] ^6- solution allows [PtV ₉ O ₂₈ ] ^7- to be surrounded by [V ₁₀ O ₂₈ ] ^6- clusters via a freeze-drying process. The V centers in both [PtV ₉ O ₂₈ ] ^7- and [V ₁₀ O ₂₈ ] ^6- were converted into V ₂ O ₅ via a calcination process to stabilize Pt center. These double separations can effectively prevent the Pt center agglomeration during the high-temperature conversion process, and achieve 100 % utilization of Pt in [PtV ₉ O ₂₈ ] ^7- . The resulting Pt-V ₂ O ₅ single-atom-site catalysts exhibit a CH ₄ yield of 247.6 μmol g ^-1  h ^-1 , 25 times higher than that of Pt nanoparticle on the V ₂ O ₅ support, which was accompanied by the lactic acid photooxidation to form pyruvic acid. Systematical investigations on this unambiguous structure demonstrate an important role of Pt-O atomic pair synergy for highly efficient CO ₂ photoreduction.
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