Synergistic Effect of Cu Single Atoms and Au–Cu Alloy Nanoparticles on TiO 2 for Efficient CO 2 Photoreduction

The synergy between metal alloy nanoparticles (NPs) and single atoms (SAs) should maximize the catalytic activity. However, there are no relevant reports on photocatalytic CO 2 reduction via utilizing the synergy between SAs and alloy NPs. Herein, we developed a facile photodeposition method to coload the Cu SAs and Au–Cu alloy NPs on TiO 2 for the photocatalytic synthesis of solar fuels with CO 2 and H 2 O. The optimized photocatalyst achieved record-high performance with formation rates of 3578.9 for CH 4 and 369.8 μmol g –1 h –1 for C 2 H 4, making it significantly more realistic to implement sunlight-driven synthesis of value-added solar fuels. The combined in situ FT-IR spectra and DFT calculations revealed the molecular mechanisms of photocatalytic CO 2 reduction and C–C coupling to form C 2 H 4 . We proposed that the synergistic function of Cu SAs and Au–Cu alloy NPs could enhance the adsorption activation of CO 2 and H 2 O and lower the overall activation energy barrier (including the rate-determining step) for the CH 4 and C 2 H 4 formation. These factors all enable highly efficient and stable production of solar fuels of CH 4 and C 2 H 4 . The concept of synergistic SAs and metal alloys cocatalysts can be extended to other systems, thus contributing to the development of more effective cocatalysts.