Developing high performance and durable electrocatalysts is crucial for the practical application of large-scale water splitting under high current density. Here, we constructed a Mott–Schottky heterojunction bifunctional electrocatalyst coating of Ni₃S₄ with Ni(OH)₂ thin film supported on Ni foam substrate (Ni₃S₄@Ni(OH)₂) for anion exchange membrane water electrolyzers (AEMWEs). Remarkably, the η₅₀₀ is as low as 274.6 mV toward the hydrogen evolution reaction and 423.8 mV toward the oxygen evolution reaction. AEMWEs deliver a stable performance that achieves current densities of 500 and 1000 mA cm⁻² at a cell voltage of 1.84 and 1.95 V, respectively. In particular, the Ni₃S₄@Ni(OH)₂ exhibits durable stability for 100 h at 500 mA cm⁻² without significant degradation and uses 0.75 kW·h of electricity less than commercial Ni foam electrode to produce each standard cubic meter of hydrogen gas at 500 mA cm⁻². The excellent performance is ascribed to the triple roles of Ni(OH)₂, which prevent the inner Ni₃S₄ from decomposing during the reaction process, promoting the dissociation of water and formation of adsorbed hydrogen intermediate and accelerating electron transfer ability due to the Mott–Schottky heterojunction between Ni(OH)₂ and Ni₃S₄. This work sheds light on the development of advanced bifunctional electrocatalysts based on non-precious transition metals for AEMWEs.

开发高性能和耐用的电催化剂对于高电流密度下大规模水分解的实际应用至关重要。在这里，我们构建了一种负载在泡沫镍基底上的Ni ₃ S ₄和 Ni(OH) _2薄膜的莫特-肖特基异质结双功能电催化剂涂层(Ni ₃ S ₄ @Ni(OH) ₂ )，用于阴离子交换膜水电解槽 (AEMWEs) ）。值得注意的是，析氢反应的η ₅₀₀低至 274.6 mV，析氧反应的 η 500 低至 423.8 mV。AEMWE 具有稳定的性能，可在 1.84 V 和 1.95 V 的电池电压下分别^{实现 500 mA cm -2和 1000 mA cm -2 的电流密度。}特别是，Ni ₃ S ₄ @Ni(OH) ₂在500 mA cm ^-2下表现出100小时的持久稳定性而没有显着降解，并且比商用泡沫镍电极少使用0.75 kW·h的电力来生产每标准立方米的^{500 mA cm -2}下的氢气。其优异的性能归因于Ni(OH) _{2的三重作用，其}在反应过程中防止内部Ni ₃ S _{4分解，促进水的离解和吸附氢中间体的形成，并加速电子转移能力。 Ni(OH) 2}和 Ni ₃ S ₄之间的莫特-肖特基异质结。这项工作揭示了用于 AEMWE 的基于非贵过渡金属的先进双功能电催化剂的开发。