Efficient CO 2 Capture and Activation on Novel Two-Dimensional Transition Metal Borides.

The large-scale production of CO 2 in the atmosphere has triggered global warming, the greenhouse effect, and ocean acidification. The CO 2 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 (M 2 B 2 , 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 CO 2 adsorption energy on MBenes ranges from -1.04 to -3.95 eV and exhibits the decreasing order as Sc 2 B 2 > Ti 2 B 2 > V 2 B 2 > Cr 2 B 2 > Mn 2 B 2 > Fe 2 B 2 . The spin-polarization calculation shows a reduction in the adsorption energy for magnetic systems. Bader charge transfer indicates the formation of CO 2 δ- moiety on the MBene surface, so-called activated CO 2 , which is essential for its reaction with other surface chemicals. Differential charge density plots reveal a significant charge accumulation around the CO 2 molecule. Our theoretical results predict the usage of new MBenes as a cost-effective catalyst for CO 2 capture and activation.