Li Wenbo, Liu Kuo, Feng Shiqiang, Xiao Yi, Zhang Linjie, Mao Jing, Liu Qian, Liu Xijun, Luo Jun, Han Lili
State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials, School of Resources, Environment and Materials, Guangxi University, Nanning, 530004 Guangxi, China.
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.
J Colloid Interface Sci. 2024 Feb;655:726-735. doi: 10.1016/j.jcis.2023.11.069. Epub 2023 Nov 11.
Alkaline H-O fuel cells and water electrolysis are crucial for hydrogen energy recycling. However, the sluggish kinetics of the hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) in an alkaline medium pose significant obstacles. Thus, it is imperative but challenging to develop highly efficient and stable non-precious metal electrocatalysts for alkaline HOR and HER. Here, we present the intriguing synthesis of well-defined NiN nanoparticles armored within an N-doped hollow carbon nanotube shell (NiN@NC) via the conversion of a hydrogen-bonded organic framework (HOF) to metal-organic framework (MOF), followed by high-temperature pyrolysis. As-developed NiN@NC demonstrates exceptional bifunctionality in alkaline HOR/HER electrocatalysis, with a high HOR limiting current density of 2.67 mA cm comparable to the benchmark 20 wt% Pt/C, while achieving a lead in overpotential of 145 mV and stronger CO-tolerance. Additionally, it achieves a low overpotential of 21 mV to attain a HER current density of 10 mA cm with long-term stability up to 340 h, both exceeding those of Pt/C. Structural analyses and electrochemical studies reveal that the remarkable bifunctional hydrogen electrocatalytic performance of NiN@NC can be ascribed to the synergistic coupling among the well-dispersed small-sized NiN nanoparticles, chain-mail structure, and optimized electronic structure enabled by strong metal-support interaction. Furthermore, theoretical calculations indicate that the high-efficiency HOR/HER observed in NiN@NC is attributed to the strong OH affinity, moderate H adsorption, and enhanced water formation/dissociation ability of the NiN active sites. This work underscores the significance of rational structural design in enhancing performance and inspires further development of advanced nanostructures for efficient hydrogen electrocatalysis.
碱性氢氧燃料电池和水电解对于氢能循环利用至关重要。然而，碱性介质中氢氧化反应（HOR）和析氢反应（HER）缓慢的动力学构成了重大障碍。因此，开发用于碱性HOR和HER的高效稳定的非贵金属电催化剂势在必行，但也具有挑战性。在此，我们展示了一种有趣的合成方法，通过将氢键有机框架（HOF）转化为金属有机框架（MOF），然后进行高温热解，制备出包裹在氮掺杂空心碳纳米管壳（NiN@NC）内的结构明确的NiN纳米颗粒。所制备的NiN@NC在碱性HOR/HER电催化中表现出卓越的双功能特性，其HOR极限电流密度高达2.67 mA cm，与基准的20 wt% Pt/C相当，同时在过电位方面领先145 mV，并且具有更强的抗CO能力。此外，它实现了21 mV的低过电位以达到10 mA cm的HER电流密度，长期稳定性高达340 h，两者均超过了Pt/C。结构分析和电化学研究表明，NiN@NC卓越的双功能氢电催化性能可归因于分散良好的小尺寸NiN纳米颗粒、链状结构以及由强金属-载体相互作用实现的优化电子结构之间的协同耦合。此外，理论计算表明，在NiN@NC中观察到的高效HOR/HER归因于NiN活性位点的强OH亲和力、适度的H吸附以及增强的水生成/解离能力。这项工作强调了合理结构设计对提高性能的重要性，并激发了进一步开发用于高效氢电催化的先进纳米结构。
