摘要: The construction of bifunctional photocatalysts that integrate oxidative and reductive sites for concurrent CO2-to-CH4 and H2O-to-H2O2 conversion under visible light remains a formidable challenge. Herein, a facile photo-deposition route was designed to support Pd nanoparticles (4.5 nm) onto SnNb2O6 nanosheets (3.5 nm) for constructing a photocatalyst (Pd-PNS). Under visible-light irradiation (λ ≥ 400 nm) and without any sacrificial agent, the optimized Pd-PNS catalyst achieves CH4 and H2O2 evolution rates of 24.3 and 79.2 μmol g-1 h-1, respectively (1:4 stoichiometry), with an apparent quantum efficiency (CH4) of 0.40 % at 420 nm, outperforming most reported systems operated under equivalent conditions. The results of characterizations reveal the formation of a strong metal-support interaction (SMSI) and a Schottky junction between Pd and SnNb2O6. SMSI causes the loss of lattice oxygens, thus generating Nb4+ and O vacancies. The Schottky junction induces the migration of photogenerated electrons to Pd NPs, while holes are trapped at lattice oxygen sites (around Nb4+), thereby improving charge transfer and separation. CO2 is reduced to CH4 on Pd NPs, while H2O is oxidized to H2O2 on Nb4+ sites, validating a true dual-site photocatalytic cycle (CO2 + 6 H2O → CH4 + 4H2O2). This work offers a valuable strategy for sacrificial-free co-production of solar fuel and green oxidant by photoinducing SMSI in a photocatalyst.