Modulating OER activity in Ni-Co-based catalysts via non-metal atom-induced electron excitation

Efficient and cost-effective oxygen evolution reaction (OER) catalysts are crucial for advancing energy conversion and storage technologies such as water electrolysis and metal-air batteries. However, the performance assessment of catalysts has been complicated by the diversity of material microstructures and electrochemical testing variables. In this study, the solvothermal and chemical vapor deposition methods were employed to synthesize several NiCo-based compounds with similar microstructures but incorporating different non-metal atoms (O, P, S, and Se). By ensuring a comparable density of electrochemically active sites, the influence of non-metal atoms on the electronic structure and catalytic activity were investigated. Characterization and molecular orbital theory confirmed that electronic coupling enabled the redistribution of atomic charge transfer in the NiCo2S4 (NCS) sample with bridging O2- and S2-. Electrochemical tests of the optimal catalyst in 1 M KOH demonstrated a lower Tafel slope (111 mV dec(-1)) and higher conductivity. The catalyst required only a 353 mV overpotential to achieve 100 mA cm(-2), and the subsequent chronoamperometry displayed a 98 % retention rate over 48 h. Such insights into the selection of non-metal atom provides a pathway for designing and preparing efficient catalysts.