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 CO₂ reduction reaction (CO₂RR) to produce C₂₊ products. Inspired by the distinct roles of Cu⁺ and Cu⁰ sites, a series of catalysts with Cu₂O/Cu heterostructures featuring well-defined Cu₂O(111)/Cu(111) interfaces were synthesized via a simple chemical reduction method based on octahedral Cu₂O catalysts. The optimized catalyst 360-Cu₂O/Cu exhibited a C₂H₄ Faradaic efficiency (FE) of 30.7% and a total C₂₊ 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, CO₂/CO cofeeding experiments, and DFT calculations collectively revealed that the Cu₂O/Cu interface enhanced the activation of CO₂ 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 C₂₊ production. This work presents a synthesis method for high-performance Cu-based CO₂RR catalysts and elucidates the interfacial effect in promoting C₂₊ selectivity, offering an insightful perspective for the future design of advanced electrocatalysts for CO₂RR.