NiMoO₄@CoFe-LDH Anode Design to Improve Oxygen Bubble Transport in Dynamic Water Electrolysis

Direct water electrolysis using renewable energy offers a promising approach to green hydrogen production. Fluctuations in power supply cause gas bubbles to accumulate on the electrode surface, leading to segmented plug flow that hampers electrode activity and durability. To tackle the ongoing challenges of gas bubble accumulation in electrocatalytic systems, this study presents a NiMoO₄@CoFe-LDH composite electrode with a 3D layered hierarchical structure designed to establish an effective gas-liquid-solid triple-phase interface. This distinct heterogeneous structure features a superhydrophilic surface, which enhances the active surface area and bubble generation sites, promoting oxygen bubble release and improving charge transfer. This bubble behavior synergistically enhances the high efficiency, dynamic response, and low load adaptability of the electrolyzer by avoiding high-current mass-transfer clogging and enhancing the adaptability to dynamic operating conditions. In 1 m KOH, the catalyst achieves a 202 mV (η@10 mA cm^-2) overpotential, with high stability of over 1000 h. The Pt/C||NiMoO₄@CoFe-LDH anion-exchange membrane electrolyzer operates efficiently and stably under fluctuating operating conditions (1.70 V@1.0 A cm^-2, 30,000 cycles), providing a new paradigm for green hydrogen anode design in scenarios of fluctuating supply of renewable energy.