First-principles study of efficient integral water-splitting and oxygen reduction reactions in transition metal single atom anchored NbTe2

Abstract

Despite the tendency of single-atom catalysts (SACs) to form nanoclusters due to high surface free energy, which reduces their catalytic activity, the high atomic utilization rate and low cost of SACs continue to make them a current research focus. Herein, the first-principles calculations are employed to design transition metal-doped NbTe₂ single-atom catalysts (TM@NbTe₂) for water-splitting reactions. The strong chemical bonds formed between the transition metal (TM) atoms and the NbTe₂ enhance catalytic activity and stability. By calculating the free energies of intermediates, Sc@NbTe₂ and V@NbTe₂ exhibited HER overpotentials of 0.086 V and 0.238 V, respectively, representing reductions of about 93 % and 80 % compared to the original NbTe₂. When studying OER performance, the optimized model TM@NbTe₂ was used to analyze and calculate the electron transfer and redistribution in the four-electron OER process, Ni@NbTe₂ and Fe@NbTe₂ had overpotentials of 0.36 V and 0.49 V, respectively, which are reductions of about 86 % and 81 % compared to the original NbTe₂. Simultaneously, both exhibited significant ORR activity. Surprisingly, Fe@NbTe₂ is considered to have the potential to become a trifunctional catalyst for HER, OER, and ORR. This study establishes a theoretical bridge towards the practical application of highly efficient NbTe₂-based water electrolysis catalysts.