Interface electronic coupling in NiCo2S4 nanorod-amorphous FeOOH nanosheets with enhanced catalytic activity in the oxygen evolution reaction

The oxygen evolution reaction (OER) involves a four-electron couple transfer step with slow reaction kinetics, which is considered a bottleneck in the water-splitting process. Therefore, exploiting earth-abundant and cost-effective OER electrocatalysts has become promising in large-scale industrial applications. Herein, a heterogeneous interface OER catalyst consisting of NiCo2S4@FeOOH-1 supported on foam nickel (NF) was synthesized through a two-step hydrothermal-chemical etching method. NiCo2S4@FeOOH-1 showed an excellent performance as an OER catalyst, requiring an overpotential of only 385.6 mV to reach 100 mA cm-2 and it exhibited a Tafel slope of 80.4 mV dec-1, indicating the rapid reaction kinetics. The NiCo2S4@FeOOH-1 catalyst also exhibited exceptional long-term stability, maintaining a consistent performance for more than 20 hours in an alkaline environment. The robust interfacial effect between NiCo2S4 and FeOOH effectively shortened the electron transport pathway, contributing to the enhancement in electrocatalytic performance. This study provides significant insights into the catalytic mechanisms and opens a pathway for the development of hierarchical structures aimed at creating highly efficient and durable OER electrocatalysts.