Cu-ZnS Modulated Multi-Carbon Coupling Enables High Selectivity Photoreduction CO to CHCHCOOH.

The direct photocatalytic conversion of CO and HO into high-value C chemicals holds great promise but remains challenging due to the intrinsic difficulty of C-C and C-C coupling processes and the lack of clarity regarding the underlying reaction mechanisms. Here, the design and synthesis of a Cu-ZnS photocatalyst featuring dispersed Cu single atoms are reported. These Cu single atoms are coordinated with S atoms, forming unique Cu-S-Zn active units with tunable charge distributions that interact favorably with surface-adsorbed intermediates. This configuration stabilizes the COHCO intermediate and facilitates its subsequent coupling with CO to form COCOHCO both thermodynamically and kinetically favorable on the Cu-ZnS surface. Notably, multiple critical C intermediates, including COCOHCO, OCCCO, and CHCHCO, are identified, providing a clear reaction pathway for CO to CHCHCOOH conversion. The Cu-ZnS photocatalyst achieves a CO to CHCHCOOH conversion rate of 0.45 µmol h¹ with an electron selectivity of 91.2%. Remarkably, in the presence of triethanolamine, the production rate increases to 16.9 µmol h¹ with a selectivity of 99.8%. These findings underscore the importance of modulating multicarbon coupling processes to enable the efficient photocatalytic transformation of CO into C products, paving the way for future advancements in sustainable chemical synthesis.