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

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.