Prediction of M₃B₄-type MBenes as Promising Catalysts for CO₂ Capture and Reduction

The rational design of novel catalysts with high activity and selectivity for carbon dioxide reduction reaction (CO2RR) is highly desired. In this work, we have extensive investigations on the properties of two-dimensional transition metal borides (MBenes) to achieve efficient CO2 capture and reduction through first-principles calculations. The results show that all the investigated M3B4-type MBene exhibit remarkable CO2 capture and activation abilities, which proved to be derived from the lone pair of electrons on the MBene surface. Then, we emphasize that the investigated MBenes can further selectively reduce activated CO2 to CH4. Moreover, a new linear scaling relationship of the adsorption energies of potential-determining intermediates (*OCH2O and *HOCH2O) versus Delta G(*OCHO) has been established, where the CO2RR limiting potentials on MBenes are determined by the different fitting slopes of Delta G(*OCH2O) and Delta G(*HOCHO), allowing significantly lower limiting potentials to be achieved compared to transition metals. Especially, two promising CO2RR catalysts (Mo3B4 and Cr3B4 MBene) exist quite low limiting potentials of -0.48 V and -0.66 V, as well as competitive selectivity concerning hydrogen evolution reactions have been identified. Our research results make future advances in CO2 capture by MBenes easier and exploit the applications of Mo3B4 and Cr3B4 MBenes as novel CO2RR catalysts.