Efficient and economical electrocatalysts should be developed for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) to split water for an extensive application prospect of green and clean hydrogen energy. Here, we develop highly efficient OER and HER electrocatalysts through the scalable fabrication of NiFeZn hydroxide nanosheets firmly arrayed on a hierarchical porous intermetallic NiZn and Ni heterojunction over nickel foam (NiFeZn-OH/NiZn-Ni/NF). One bimodal porous NiZn intermetallic/Ni layer is in situ constructed on the nickel foam surface to maximize the exposure of catalytic sites and build firm NiFeZn-OH nanosheets via the redox reaction with FeCl₃. NiFeZn-OH/NiZn-Ni/NF shows low overpotentials of η_50/600 around 235/284 mV for OER and η_50/600 around 73/212 mV for HER, small Tafel slopes of 46.1 and 41.1 mV dec⁻¹, and prolonged catalytic durability in an alkaline medium because of the strong synergistic effects of Zn doping, multiple interface engineering, and integral three-dimensional free-standing scaffold. As bifunctional catalysts, NiFeZn-OH/NiZn-Ni/NF required a low electrolytic voltage of 1.49 V at 20 mA cm⁻² (1.61 V at 100 mA cm⁻²) with a sustained and stable output for 40 h during water splitting. This work might provide insights into the exploration of low-cost and highly efficient intermetallic/multimetallic hydroxide heterostructured electrocatalysts for practical overall water splitting.

应开发高效、经济的电催化剂，用于析氧反应（OER）和析氢反应（HER）分解水，以获得绿色清洁氢能源的广泛应用前景。在这里，我们通过在镍泡沫（NiFeZn-OH/NiZn-Ni/NF）上牢固排列在分层多孔金属间 NiZn 和 Ni 异质结上的 NiFeZn 氢氧化物纳米片的可扩展制造，开发了高效的 OER 和 HER 电催化剂。在泡沫镍表面原位构建一个双峰多孔 NiZn 金属间化合物/Ni 层，以最大限度地暴露催化位点并通过与 FeCl ₃的氧化还原反应构建坚固的 NiFeZn-OH 纳米片。NiFeZn-OH/NiZn-Ni/NF 显示出η _{50/600 的}低过电位OER约为 235/284 mV，HER 的η _50/600约为 73/212 mV，Tafel 斜率为 46.1 和 41.1 mV dec ^{- 1 小}，并且由于 Zn 掺杂的强协同效应，延长了在碱性介质中的催化耐久性，多界面工程，一体式三维独立式脚手架。作为双功能催化剂，NiFeZn-OH/NiZn-Ni/NF 在 20 mA cm ^{- 2 时}需要 1.49 V 的低电解电压（在 100 mA cm ^{-2 时为}1.61 V) 在水分解过程中持续稳定输出 40 小时。这项工作可能为探索用于实际整体水分解的低成本和高效金属间/多金属氢氧化物异质结构电催化剂的探索提供见解。