Bismuth clusters pinned on TiO2 porous nanowires boosting charge transfer for CO2 photoreduction to CH4

Artificial photosynthesis in carbon dioxide (CO 2 ) conversion into value-added chemicals attracts considerable attention but suffers from the low activity induced by sluggish separation of photogenerated carriers and the kinetic bottleneck-induced unsatisfied selectivity. Herein, we prepare a new-style Bi/TiO 2 catalyst formed by pinning bismuth clusters on TiO 2 nanowires through being confined by pores, which exhibits high activity and selectivity towards photocatalytic production of CH 4 from CO 2 . Boosted charge transfer from TiO 2 through Bi to the reactants is revealed via in situ X-ray photon spectroscopy and time-resolved photoluminescence (PL). Further, in situ Fourier transform infrared results confirm that Bi/TiO 2 not only overcomes the multi-electron kinetics challenge of CO 2 to CH 4 via boosting charge transfer, but also facilitates proton production and transfer as well as the intermediates ⋆ CHO and ⋆ CH 3 O generation, ultimately achieving the tandem catalysis towards methanation. Theoretical calculation also underlies that the more favorable reaction step from ⋆ CO to ⋆ CHO on Bi/TiO 2 results in CH 4 production with higher selectivity. Our work brings new insights into rational design of photocatalysts with high performance and the formation mechanism of CO 2 to CH 4 for solar energy storage in future.