Experimental and Computational Investigation of Au₂₅ Clusters and CO₂: A Unique Interaction and Enhanced Electrocatalytic Activity

Abstract

Atomically precise, inherently charged Au₂₅ clusters are an exciting prospect for promoting catalytically challenging reactions, and we have studied the interaction between CO₂ and Au₂₅. Experimental results indicate a reversible Au₂₅–CO₂ interaction that produced spectroscopic and electrochemical changes similar to those seen with cluster oxidation. Density functional theory (DFT) modeling indicates these changes stem from a CO₂-induced redistribution of charge within the cluster. Identification of this spontaneous coupling led to the application of Au₂₅ as a catalyst for the electrochemical reduction of CO₂ in aqueous media. Au₂₅ promoted the CO₂ → CO reaction within 90 mV of the formal potential (thermodynamic limit), representing an approximate 200–300 mV improvement over larger Au nanoparticles and bulk Au. Peak CO₂ conversion occurred at −1 V (vs RHE) with approximately 100% efficiency and a rate 7–700 times higher than that for larger Au catalysts and 10–100 times higher than those for current state-of-the-art processes