Intercalation of Pt(II) Terpyridine Complexes into Layered K₄Nb₆O₁₇ and Visible-Light-Driven Photocatalytic Production of H₂

Direct intercalation of a [Pt(tpy)Cl]Cl (tpy: terpyridine) complex into a layered niobate (K 4 Nb 6 O 17 ) has been successfully accomplished with the aim of developing a recyclable photocatalyst. Pt L III -edge X-ray absorption fine structure measurement suggests that the Pt complex is intercalated into the interlayer space accompanied with ligand exchange of a Pt–Cl bond. Unlike the free Pt complex in solution, the intercalated Pt complex exhibits photoluminescence emission at room temperature due to a metal–metal-to-ligand charge-transfer ( 3 MMLCT) transition near 630 nm, originating from short Pt···Pt interactions (<3.5 Å). Such intercalated Pt complexes, which are in close proximity to each other, behave as a single-component bifunctional catalyst, enabling both visible light sensitization and H 2 production in aqueous media consisting of a sacrificial electron donor (EDTA). The turnover number based on Pt is in good accordance with the increasing intensity of luminescence emission due to the 3 MMLCT states. Moreover, leaching and agglomeration of the active Pt species is not observed, and the recovered photocatalyst can be recycled without deterioration in its catalytic activity.