Gong Xi-Song, Liu Xing, Zhou Jian
Chongqing Key Laboratory of Inorganic Functional Materials, College of Chemistry, Chongqing Normal University, Chongqing, 401331, PR China.
Nanoscale. 2025 Feb 27;17(9):5301-5315. doi: 10.1039/d4nr05248j.
The development of environmentally friendly, high-efficiency, stable, earth-abundant and non-precious metal-based electrocatalysts with fast kinetics and low overpotential for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is of exceeding significance but still challenging. Herein, a bifunctional electrode of unique hierarchical NiFe-LDH/Ni/NiCoS/NF (NiFe-LDH = nickel-iron layered double hydroxide and NF = nickel foam) electrocatalytic architecture, which is built up from NiFe-LDH nanosheets, Ni nanoparticles and NiCoS nanoneedles sequentially arrayed on a porous NF substrate, has been prepared by a facile hydrothermal and electrodeposition method. This electrocatalytic architecture is binder-free and its outer NiFe-LDH nanosheets can effectively prevent the oxidation of inner Ni nanoparticles and corrosion of NiCoS nanoneedles during water electrolysis. The integration of effective HER Ni nanoparticles into OER NiFe-LDH and NiCoS electrocatalysts can not only overcome the disadvantage of their poor electrical conductivity, but also greatly improve their HER and OER activities, owing to the unique hierarchical heterostructure and multicomponent synergies among Ni, NiFe-LDH, and NiCoS. Consequently, this electrode shows better OER performance with ultra-low overpotential of 192 mV at 10 mA cm, a small Tafel slope of only 37 mV dec and high stability in comparison with commercial RuO, and also exhibits excellent HER activity with a low overpotential of 83 mV at 10 mA cm. More importantly, the NiFe-LDH/Ni/NiCoS/NF composite serves as anode and cathode for overall water splitting, and it requires a low cell potential of only 1.53 V to reach a current density of 10 mA cm, which evidently exceeds that of the standard Pt-C/NF//RuO/NF cell of 1.61 V. This work provides a feasible strategy to prepare high-efficiency, low-cost and non-precious metal-based electrocatalysts for overall water splitting.
开发具有快速动力学、低过电位的环境友好型、高效、稳定、储量丰富且非贵金属基的析氧反应（OER）和析氢反应（HER）电催化剂具有极其重要的意义，但仍具有挑战性。在此，通过简便的水热和电沉积方法制备了一种独特的分级NiFe-LDH/Ni/NiCoS/NF（NiFe-LDH = 镍铁层状双氢氧化物，NF = 泡沫镍）电催化结构的双功能电极，该结构由依次排列在多孔NF基底上的NiFe-LDH纳米片、Ni纳米颗粒和NiCoS纳米针组成。这种电催化结构无需粘合剂，其外层的NiFe-LDH纳米片可有效防止内部Ni纳米颗粒在水电解过程中被氧化以及NiCoS纳米针被腐蚀。将有效的HER Ni纳米颗粒整合到OER NiFe-LDH和NiCoS电催化剂中，不仅可以克服它们电导率差的缺点，还由于Ni、NiFe-LDH和NiCoS之间独特的分级异质结构和多组分协同作用，大大提高了它们的HER和OER活性。因此，与商业RuO相比，该电极在10 mA cm时具有192 mV的超低过电位，仅37 mV dec的小塔菲尔斜率和高稳定性，展现出优异的OER性能，并且在10 mA cm时具有83 mV的低过电位，表现出出色的HER活性。更重要的是，NiFe-LDH/Ni/NiCoS/NF复合材料用作全水解的阳极和阴极，在达到10 mA cm的电流密度时仅需1.53 V的低电池电位，明显超过标准Pt-C/NF//RuO/NF电池的1.61 V。这项工作为制备用于全水解的高效、低成本且非贵金属基电催化剂提供了一种可行的策略。
