Efficient CO₂ Capture and Activation on Novel Two-Dimensional Transition Metal Borides

The large-scale production of CO₂ in the atmosphere has triggered global warming, the greenhouse effect, and ocean acidification. The CO₂ conversion to valuable chemical products or its capture and storage are of fundamental importance to mitigate the greenhouse effect on the environment. Therefore, exploring new two-dimensional (2D) materials is indispensable due to their potential intriguing properties. Here, we report a new family of 2D transition metal borides (M₂B₂, M = Sc, Ti, V, Cr, Mn, and Fe; known as MBenes) and demonstrate their static and dynamic stability. These MBenes show a metallic nature and exhibit excellent electrical conductivity. The CO₂ adsorption energy on MBenes ranges from -1.04 to -3.95 eV and exhibits the decreasing order as Sc₂B₂ > Ti₂B₂ > V₂B₂ > Cr₂B₂ > Mn₂B₂ > Fe₂B₂. The spin-polarization calculation shows a reduction in the adsorption energy for magnetic systems. Bader charge transfer indicates the formation of CO₂^δ- moiety on the MBene surface, so-called activated CO₂, which is essential for its reaction with other surface chemicals. Differential charge density plots reveal a significant charge accumulation around the CO₂ molecule. Our theoretical results predict the usage of new MBenes as a cost-effective catalyst for CO₂ capture and activation.