Molybdenum in situ etching-treated ultrathin NiFeMo LDHs nanosheet arrays as a performance anodic catalyst for efficient industrial production of hydrogen

Water-splitting is a critical technology for the conversion and storage of renewable energy. The slow anodic process dynamics with high overpotential greatly limit the commercialization of electrolytic hydrogen production. Herein, we proposed an electrochemical in situ etching method to achieve molybdenum component-controlled dissolution of ultrathin NiFeMo layered double hydroxides (LDHs) nanosheet arrays on nickel-iron foam (NFF) to create in situ reconstructed oxygen evolution reaction (OER) active sites in LDHs. The Mo-etched material exhibited significantly enhanced catalytic performance and demonstrated exceptional OER activity in alkaline media, achieving a low overpotential of 288 mV at 10 mA cm^-2 and 784 mV at 1000 mA cm^-2, along with a desired Tafel slope of 43.52 mV dec^-1. The enhanced reaction kinetics was contributed by Mo doping-induced electronic structure optimization and interfacial stabilization. Furthermore, an assembled alkaline electrolyzer with NiFeMo/NFF maintained a stable electrolysis voltage (1.695 ± 0.022 V) under simulated industrial fluctuating conditions (30 wt% KOH, 85 °C, 3000 A m^-2) for 210 h, exhibiting a super-low voltage decay rate (0.1 mV h^-1). The superior performance-stability properties of the new catalyst displayed new material design strategies for efficient industrial hydrogen-production systems.