Protective structure coupled dual electron transfer channels for enhancing the activity and stability of photocatalytic CO2 reduction to C2 liquid products

Developing highly efficient and stable photocatalysts for CO2 reduction toward C-C coupling to produce value-added chemicals remains a significant challenge. In this work, we designed a photocatalyst (PdxCuy/ZnO-CN) with a protective structure and dual electron transfer pathways to address the long-standing trade-off between activity and stability. In pure water, the yields of acetate and ethanol over PdxCuy/ZnO-CN reach up to 97.6 and 74.6 μmol g−1 h−1, respectively, with a total C2 product selectivity of 97.8 %. Notably, the N-doped carbon (CN) template effectively transfers photogenerated electrons from the external ZnO to the protected PdCu single-atom alloy (SAAs), endowing PdxCuy/ZnO-CN with the capability to continuously produce C2 products for 33 hours. Experimental and theoretical calculation results indicate that the external (ZnO→CN→PdCu SAAs) and internal (Pd→Cu) electron transfer pathways significantly reduce the rate-determining step of *CO hydrogenation, thereby facilitating the formation of *CHCHO and *CH2CO intermediates. This work provides a promising platform and approach for designing efficient and stable photocatalytic CO2-to-C2 product systems. [Display omitted] •PdCu/ZnO-CN with PdCu single-atoms alloys for driving CO2 photoreduction to C2 liquid products.•The external (ZnO→CN→PdCu SAAs) and internal (Pd→Cu) electron transfer pathways significantly reduce the rate-determining step of *CO hydrogenation.•PdCu SAAs effectively reduces the free energy of the rate-determining step *CO → *COH, thereby promoting the formation of key intermediates *CHCHO and *CH2CO.