Electronic Properties and CO 2 -Selective Adsorption of (NiB) n ( n = 1~10) Clusters: A Density Functional Theory Study.

In this study, we investigated the electronic properties and selective adsorption for CO 2 of nickel boride clusters (NiB) n , (n = 1~10) using the first principles method. We optimized the structures of the clusters and analyzed their stability based on binding energy per atom. It was observed that (NiB) n clusters adopt 3D geometries from n = 4, which were more stable compared to the plane clusters. The vertical electron affinity, vertical ionization energy, chemical potential, and highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap were calculated. Our results revealed that (NiB) 6 and (NiB) 10 , with high chemical potential, exhibit a higher affinity for CO 2 adsorption due to a charge delivery channel that forms along the Ni→B→CO 2 path. Notably, (NiB) 10 demonstrated a more practical CO 2 desorption temperature, as well as a broader window for the selective adsorption of CO 2 over N 2 . The density of states analysis showed that the enhanced CO 2 adsorption on (NiB) 10 can be attributed to the synergistic effect between Ni and B, which provides more active sites for CO 2 adsorption and promotes the electron transfer from the surface to the CO 2 molecule. Our theoretical results imply that (NiB) 10 should be a promising candidate for CO 2 capture.