Cascaded *CO-*COH Intermediates on a Nonmetallic Plasmonic Photocatalyst for CO 2 -to-C 2 H 6 with 90.6 % Selectivity.

Oxygen vacancies (O V ) in nonmetallic plasmonic photocatalysts can decrease the energy barrier for CO 2 reduction, boosting C1 intermediate production for potential C 2 formation. However, their susceptibility to oxidation weakens C1 intermediate adsorption. Herein we proposed a "photoelectron injection" strategy to safeguard O V in W 18 O 49 by creating a W 18 O 49 /ZIS (W/Z) plasmonic photocatalyst. Moreover, photoelectrons contribute to the local multi-electron environment of W 18 O 49 , enhancing the intrinsic excitation of its hot electrons with extended lifetimes, as confirmed by in situ XPS and femtosecond transient absorption analysis. Density functional theory calculations revealed that W/Z with O V enhances CO 2 adsorption, activating *CO production, while reducing the energy barrier for *COH production (0.054 eV) and subsequent *CO-*COH coupling (0.574 eV). Successive hydrogenation revealed that the free energy for *CH 2 CH 2 hydrogenation (0.108 eV) was lower than that for *CH 2 CH 2 desorption for C 2 H 4 production (0.277 eV), favouring C 2 H 6 production. Consequently, W/Z achieves an efficient C 2 H 6 activity of 653.6 μmol g -1  h -1 under visible light, with an exceptionally high selectivity of 90.6 %. This work offers a new strategy for the rational design of plasmonic photocatalysts with high selectivity for C 2+ products.