Enhancing the Selectivity of Cu ₂ O-Based Catalysts for Multicarbon Products via Interface Engineering

Currently, it is a significant challenge to design and fabricate Cu-based catalysts capable of efficiently catalyzing the electrochemical CO 2 reduction reaction (CO 2 RR) to produce C 2+ products. Inspired by the distinct roles of Cu + and Cu 0 sites, a series of catalysts with Cu 2 O/Cu heterostructures featuring well-defined Cu 2 O(111)/Cu(111) interfaces were synthesized via a simple chemical reduction method based on octahedral Cu 2 O catalysts. The optimized catalyst 360-Cu 2 O/Cu exhibited a C 2 H 4 Faradaic efficiency (FE) of 30.7% and a total C 2+ FE of 44.3%, with a partial current density of 12.9 mA cm –2 in an H-cell. In the flow cell, FE C2+ increased to 53.2% at a constant current density of 50 mA cm –2 . In situ ATR-FTIR spectroscopy, CO 2 /CO cofeeding experiments, and DFT calculations collectively revealed that the Cu 2 O/Cu interface enhanced the activation of CO 2 molecules and significantly reduced the energy barriers for both the hydrogenation of the key intermediate *CO and the subsequent asymmetric C–C coupling between *CO and *COH, thereby promoting the formation of the *COCOH intermediate for efficient C 2+ production. This work presents a synthesis method for high-performance Cu-based CO 2 RR catalysts and elucidates the interfacial effect in promoting C 2+ selectivity, offering an insightful perspective for the future design of advanced electrocatalysts for CO 2 RR.