Electrocatalytic property of water oxidation reaction depends on charging state of intermediates on Ag-M (M = Fe, co, Ni, Cu) in alkaline media

DFT calculations are performed to investigate the water oxidation reaction intermediates on Ag₂M (M = Fe, Co, Ni, Cu), and Pt₃ clusters in alkaline media both in the gas and solution (water) phases in the neutral and charged states. The calculated results revealed that the neutral and anionic clusters were found to be more suitable catalysts than cationic clusters because of weakly bonded water oxidation reaction intermediates. In addition, the calculated structural parameters of the water oxidation intermediates with Ag₂M (M = Fe, Co, Ni, Cu) clusters revealed that M-OH bond strengths are found to be in the order of Cu < Ni < Co < Fe. Conclusively, Ag₂Cu cluster was determined to be the best electrocatalyst regarding oxygen evolution reaction via 4e transfer, which is consistent with results on larger Ag₂M clusters (13 atoms) and periodic Ag-M nanoalloys due to weaker binding energies of the water oxidation intermediates.