Constructing a square-like copper cluster to boost C–C coupling for CO2 electroreduction to ethylene

Abstract

The CO₂ electroreduction reaction (CO₂ER) to ethylene (C₂H₄) offers the dual promise of lowering CO₂ emission while storing energy from renewable electricity, for which the development of highly efficient electrocatalysts is of great significance. Herein, by means of density functional theory (DFT) computations, we designed an electrocatalyst for CO₂-to-C₂H₄ conversion by anchoring a Cu₅ cluster supported on a MoS₂ monolayer with an S monovacancy (Cu₅@MoS₂). Our results revealed that one Cu atom of the Cu₅ cluster was embedded into the framework of the defective MoS₂ monolayer, while the other four Cu atoms form a square-like island over the substrate surface. Interestingly, the C–C coupling between two *CO species can easily occur on the unique square-like active site with a low kinetic barrier of 0.56 eV to form the key *C₂O₂ intermediate, which can then be hydrogenated to the C₂H₄ product with a very low limiting potential (−0.32 eV). Significantly, alkaline conditions (pH = 13) are beneficial to further promote C₂H₄ synthesis. Our work may offer a new avenue to precisely modulate the structures of Cu clusters for converting CO₂ into high-value target products.