Entropy-Derived\nSynthesis of the CuPd Sub-1nm Alloy\nfor CO<sub>2</sub>‑to-acetate Electroreduction

Bimetallic\nalloys exhibit remarkable properties in catalysis and\nenergy storage, while their precise synthesis at the subnanoscale\nremains a formidable challenge due to their immiscible nature in thermodynamics.\nIn this study, we engineer an atomically dispersed CuPd alloy with\nan average size of 1.5 nm loaded on CuO and phosphomolybdic acid (PMA)\ncoassembly subnanosheets (CuO-PMA SNSs). Driven by the high vibrational\nentropy, Cu atoms could escape from CuO supports and bond with adjacent\nPd single atoms, leading to the in situ formation of CuPd alloys.\nFurthermore, this strategy can also be utilized for synthesizing the\nZnPt alloy with an average size of 1 nm, thereby providing a general\npathway for the design of immiscible subnanoalloys. The fully exposed\nCu–Pd pairs in CuPd subnanoalloys significantly enhance the\nadsorption and coverage of surface *CO during the electrochemical\nreduction of CO<sub>2</sub>, thereby leading to enhanced stability\nof ethenone intermediates and facilitating the production of C<sub>2</sub> compounds. The resulting CuPd subnanoalloy exhibits a remarkable\nFaradaic efficiency of 46.5 ± 2.1% for CO<sub>2</sub>-to-acetate\nelectroreduction and achieves a high acetate productivity of 99 ±\n2.8 μmol cm<sup>–2</sup> at −0.7 V versus RHE.