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

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