Tailoring Si12C12 nanocluster with late first-row transition metals: A promising approach during single-atom catalysis toward hydrogen evolution reaction (HER)

Abstract

Hydrogen evolution reaction (HER) has gained a great interest in recent years because it provides the cleanest fuel (H2). One of the most demanding things required for this reaction is an efficient and cost-effective catalyst. Single atom catalysis is one of the most remarkable strategies in this regard. Herein, transition metals adsorbed silicon carbide nanocages (TM@Si12C12; TM = Zn, Fe, Co, Cu, Ni) are investigated as single atom catalysts in order to search less expensive electrocatalysts with excellent efficiency for HER. The pure and hydrogen adsorbed TM@Si12C12 show geometric and thermodynamic stability which illustrates their practical utility. Interaction energies obtained range from −0.70 to −5.73 eV, and it is suggested that Cu@Si12C12 may play an excellent role in HER due to its lowest Gibbs free energy of −0.17 eV (near to zero). In this work, we investigated electronic properties through natural bond orbital (NBO) analysis of selected TM@SiC. According to NBO calculations, it is observed that charge is transferred from adsorbed transition metals towards nanocage. After H adsorption, NBO charge is transferred to hydrogen which shows the adsorption properties of H. In case of HOMO-LUMO energy gap, it is observed that transition metal adsorbed complexes have small energy gaps between 2.17 and 2.77 eV but after adsorption of hydrogen, this energy gap increases to lie in the range of to change from 2.93 to 3.12 eV, which also verified the electronic stability of H adsorbed species. The noncovalent interactions are estimated through NCI analysis. The density of states analysis gives insight about the energy states of occupied and unoccupied orbitals of electrons. The highest thermodynamic stability and electronic conductivity of transition metal adsorbed silicon carbide suggested it as an excellent supportive surface for HER.