Surface charge as activity descriptors for electrochemical CO2 reduction to multi-carbon products on organic-functionalised Cu

Tuning CO2 electrocatalysis to achieve multi-carbon products is interesting yet challenging. Here the authors report a histidine-functionalized Cu catalyst for CO2 reduction to multi-carbon products and reveal the correlation between catalyst surface charge and catalytic performance. Intensive research in electrochemical CO2 reduction reaction has resulted in the discovery of numerous high-performance catalysts selective to multi-carbon products, with most of these catalysts still being purely transition metal based. Herein, we present high and stable multi-carbon products selectivity of up to 76.6% across a wide potential range of 1 V on histidine-functionalised Cu. In-situ Raman and density functional theory calculations revealed alternative reaction pathways that involve direct interactions between adsorbed histidine and CO2 reduction intermediates at more cathodic potentials. Strikingly, we found that the yield of multi-carbon products is closely correlated to the surface charge on the catalyst surface, quantified by a pulsed voltammetry-based technique which proved reliable even at very cathodic potentials. We ascribe the surface charge to the population density of adsorbed species on the catalyst surface, which may be exploited as a powerful tool to explain CO2 reduction activity and as a proxy for future catalyst discovery, including organic-inorganic hybrids.

Automated summary

The authors report a histidine-functionalized Cu catalyst for CO2 reduction to multi-carbon products and reveal the correlation between catalyst surface charge and catalytic performance. The histidine-functionalized Cu exhibits high and stable selectivity for multi-carbon products across a wide potential range. The results provide important insights for explaining CO2 reduction activity and discovering new catalysts.