ZnSnAuBiCuO-Derived Electrocatalysts Rich in Grain Boundaries for CO Reduction to n-Propanol

Electrocatalytic carbon monoxide reduction (CORR) to n-propanol, powered by renewable energy, offers a promising approach for energy storage and carbon recycling, while avoiding the high CO2 emissions associated with current industrial n-propanol production methods. However, electrocatalysts capable of achieving both high Faradaic efficiency for CO reduction to n-propanol and long-term durability remain scarce. While monometallic and bimetallic dilute Cu-based alloys have been studied extensively for electrochemical CO2 reduction (CO2RR) and CORR, multimetallic (≥5 elements) electrocatalysts are less explored. Here we screen and investigate the electrocatalytic CORR performance of multimetallic electrocatalysts. Notably, the ZnSnAuBiCuO catalyst achieves Faradaic efficiencies (FE) of 47 ± 1% for n-propanol production, while demonstrating stable performance for 60 h at 100 mA cm-2. The enhanced CORR performance is attributed to the higher grain boundary density and the higher Cu valence state compared to CuO. Calculation is consistent with the possibility that grain boundaries are, in the context of n-propanol production, energetically favorable, compared to within-grain sites. The stable electrosynthesis of n-propanol with high FE by ZnSnAuBiCuO may motivate the exploration of other multimetallic systems, which have vast compositional space.