Steering Multistep Charge Transfer for Highly Selectively Photocatalytic Reduction of CO2 into CH4 over Pd/Cu2O/TiO2 Ternary Hybrid

Due to the low charge separation efficiency and high stability of the CO 2 molecule, photoreduction of CO 2 into a single multielectron product such as CH 4 with a simultaneous high conversion rate and selectivity is challenging. Therefore, it is highly desirable to accelerate charge separation and transfer and provide an electron‐enriched catalyst surface for the deep reduction of CO 2 . Herein, a Pd/Cu 2 O/TiO 2 ternary hybrid photocatalyst consisting of Pd nanoparticles (NPs) and Cu 2 O NPs‐decorated TiO 2 nanosheets is rationally designed, and highly selective photocatalytic photoreduction of CO 2 into CH 4 is achieved. The Pd/Cu 2 O/TiO 2 photocatalyst shows a high CH 4 production rate of 42.8 μmol g −1 h −1 with an extremely high selectivity of 99.5%. This CH 4 production rate is 61.1, 5.4, and 2.8 times higher than the bare TiO 2 , Cu 2 O/TiO 2 , and Pd/TiO 2 , respectively. In this Pd/Cu 2 O/TiO 2 hybrid, a consecutive multistep charge transfer is steered between the Cu 2 O/TiO 2 heterojunction and Pd, ensures accelerated charge separation and transfer, and leads to the formation of a spatially separated electron‐enriched surface (Pd) and hole‐enriched surface (Cu 2 O). This spatially oriented charge transfer and the charge‐enriched catalyst surface synergistically contribute to the simultaneous high conversion rate and selectivity of CH 4 .