Interface-Engineered Electrochemical CO2 Reduction to Formate Coupled with Enzymatic Dihydroxyacetone Production

While the electroreduction of CO2 to high-value chemicals provides a revolutionary strategy for achieving sustainable development, the direct synthesis of multi-carbon products remains a prominent challenge. Herein, an integrated strategy that combines renewable electrochemical carbon dioxide reduction reactions (eCO2RR) with enzyme cascades for the high-value-added production of dihydroxyacetone is proposed. Specifically, bismuth nanocatalysts were doped with sulfur to modulate the surface electronic structure, leading to the significantly accelerated formation of *HCOO intermediates. Consequently, a 94.7% formate Faradaic efficiency was attained at 300 mA cm-2, and good long-term catalytic stability was achieved. Moreover, a 4 cm2 membrane electrode electrolyzer was employed with a 0.1 M KHCO3 neutral electrolyte to concentrate the formate product and protect the downstream enzymes from the alkaline electrolyte. The cofactor NADH was directly regenerated using a copper foam electrode, driving an enzymatic cascade to convert formate to 2.77 g L-1 dihydroxyacetone without external carbon supplementation. This work presents a DHA synthesis method, which is solely electricity-driven and involves the direct reaction of CO2 and H2O, without requiring any externally supplied cofactors or stoichiometric reductants. By exploiting the fine selectivity and efficiency of enzyme catalysis, this formate-mediated pathway maximizes carbon utilization and significantly expands the chemical space accessible to carbon dioxide.