Mo2B2O2 MBene for Efficient Electrochemical CO Reduction to C2 Chemicals: Computational Exploration

Abstract

Emerging as a new class of two-dimensional materials with atomically thin layers, MBenes have great potential for many important applications such as energy storage and electrocatalysis. Toward mitigating carbon footprint, there has been increasing interest in CO₂/CO conversion on MBenes, but mostly focused on C₁ products. C₂₊ chemicals generally possess higher energy densities and wider applications than C₁ counterparts. However, C–C coupling is technically challenging because of high energy requirement and currently few catalysts are suited for this process. Here, we explore electrochemical CO reduction reaction to C₂ chemicals on Mo₂B₂O₂ MBene via density-functional theory calculations. Remarkably, the most favorable CO–COH coupling is revealed to be a spontaneous and barrierless process, making Mo₂B₂O₂ an efficient catalyst for C–C coupling. Among C₁ and C₂ chemicals, ethanol is predicted to be the primary product. Furthermore, by charge and bond analysis, it is unraveled that there exist significantly more unbonded electrons in the C atom of intermediate *COH than other C₁ intermediates, which is responsible for the facile C–C coupling. From an atomic scale, this work provides microscopic insight into C–C coupling process and suggests Mo₂B₂O₂ a promising catalyst for electrochemical CO reduction to C₂ chemicals.