Two-dimensional MBene: a comparable catalyst to MXene for effective CO2RR towards C1 products

Abstract

Electrochemical CO₂ reduction reaction (CO₂RR) to high-value-added products is one of the most promising strategies for mitigating the greenhouse effect and energy shortage. Two-dimensional (2D) MXene materials are regarded as promising catalysts for electrocatalysis, and the boron-analogs of MXenes, 2D transition metal borides (MBenes), may exhibit superior CO₂RR performance owing to their unique electronic properties. Herein, a novel 2D transition metal boride, MoB, is theoretically evaluated as a potential catalyst for the CO₂RR by comparing it with traditional Mo₂C. MoB shows metallic nature and exhibits excellent electrical conductivity. MoB can effectively activate CO₂ with a larger interaction energy of −3.64 eV than that of Mo₂C. Both density of states and charge difference density reveal a significant charge transfer from MoB to CO₂. MoB shows higher catalytic selectivity due to its inhibited hydrogen evolution reaction and low reaction energy for the CO₂RR. At potentials more negative than −0.62 V, the CO₂RR on MoB becomes a high-throughput reaction process towards CH₄. This work discovered that MoB exhibited comparable CO₂RR performance to Mo₂C and forecasted MBenes as promising catalysts for electrocatalysis.