A layered lead halide framework intercalated with Ru(bpy)3 for efficient CO2 photoreduction

Three-dimensional lead halide hybrids exhibit excellent photophysical properties but suffer from inherent instability. In contrast, two-dimensional layered lead halides offer enhanced environmental stability, yet their strongly bound excitons restrict efficient charge transport. Here we present a covalent intercalation strategy involving the benchmark photosensitizer [Ru(bpy)₃]²⁺ into a layered lead halide framework, featuring cationic [Pb₂₃X₄₂]⁴⁺ (X^- = Cl^- or Br^-) layers pillared by [Ru(bpy)₃]²⁺ ligands via Pb²⁺-carboxylate coordination. This hybrid material achieves nearly full visible-light absorption and efficient photoinduced charge transfer from [Ru(bpy)₃]²⁺ to the lead halide layers. This affords efficient CO₂-to-CO photoreduction with an apparent quantum efficiency of ~3.0% at 500 nm, exceeding the performance of all previously reported organolead halide photocatalysts. Mechanistic studies indicate that the [Ru(bpy)₃]²⁺ ligands enhance charge transport to Pb²⁺ sites, facilitating CO₂ activation and reducing the reaction barrier for the *COOH intermediate. This work establishes a paradigm for intercalation chemistry in robust layered lead halide hybrids.