Stepwise Ligand Tuning of Copper Clusters for CO ₂ Electroreduction Pathway Control

High Resolution Image Download MS PowerPoint Slide Copper-based materials with tailored surface modifications hold great potential for electrocatalytic CO 2 reduction reactions (CO 2 RR), particularly in the selective formation of multicarbon (C 2+ ) products. However, progress remains limited by an incomplete understanding of the atomic-level coordination environment and associated physicochemical properties. Here, we investigate ligand effects on CO 2 RR performance by a series of atomically precise Cu clusters–Cu 6 (X) 6, where X represents the thiourea derivative. Notably, Cu 6 (N,N′-diphenylthiourea) 6 achieves maximum Faradaic efficiency of 80.6% toward C 2 products at 150 mA cm −2, demonstrating an optimized balance of multiple proton-coupled electron transfer pathways. In contrast, the incorporation of an electron-donating ligand (−NMe 2 ) shifts approximately 30% of C 2 products to CH 4, while an electron-withdrawing ligand (−CF 3 ) increases the proportion of C 1 products driven by modified hydrophilicity and electron-donating capability. These findings provide critical insights into atomic-level surface engineering and offer valuable guidance for the rational design of CO 2 RR catalysts.