Tuning of B12 nanoring with first row transition metals toward potential application as single atom catalysts for hydrogen evolution reaction

In pursuit of sustainable energy, hydrogen (H₂) has emerged as a highly promising green energy fuel. Water splitting is a well-established method for H₂ production, but its practical implementation requires efficient and low cost electrocatalysts. Recently, single atom catalysts (SACs) have attracted attention due to their high thermal stability, large surface area and good electrical conductivity. Herein, the viability of first row transition metals (TMs = Sc -Zn) doped boron twelve nanoring (TMs@B12) is investigated as SACs for hydrogen evolution reaction (HER) using density functional theory (DFT) calculations. The analysis includes geometric optimization, electronic structure, and electrochemical properties of the designed TMs@B12 complexes. All complexes exhibit thermodynamic stability favorable for practical application. Natural bond orbital (NBO) analysis reveals significant charge transfer between the TMs@B12 framework and adsorbed hydrogen, confirming strong electronic interactions. Evaluation of the rate determining steps shows that V@B12, Ti@B12 and Sc @B12 have the lowest energy barriers, promoting efficient HER kinetics. Among the screened SACs, Sc @B12 exhibits the most favorable hydrogen adsorption free energy (∆ G _H* = -0.313 eV) and its therefore identified as the most balanced candidate from the volcano descriptor perspective, whereas V@B12 complex showed the lowest calculated Heyrovsky activation barrier. These findings provide valuable guidance for the rational design of efficient and cost-effective single atom electrocatalysts for green hydrogen production.