Transition metal nanostructures are widely regarded as important catalysts to replace the precious metal Pt for hydrogen evolution reaction (HER) in water splitting. However, it is difficult to obtain uniform-sized and ultrafine metal nanograins through general high-temperature reduction and sintering processes. Herein, a novel method of chemical energy-driven lithiation is introduced to synthesize transition metal nanostructures. By taking advantage of the slow crystallization kinetics at room temperature, more surface and boundary defects can be generated and remained, which reduce the atomic coordination number and tune the electronic structure and adsorption free energy of the metals. The obtained Ni nanostructures therein exhibit excellent HER performance. In addition, the bimetal of Co and Ni shows better electrocatalytic kinetics than individual Ni and Co nanostructures, reaching 100 mA cm⁻² at a low overpotential of 127 mV. The high HER performance originates from well-formed synergistic effect between Ni and Co by tuning the electronic structures. Density functional theory simulations confirm that the bimetallic NiCo possesses a low Gibbs free energy of hydrogen adsorption, which are conducive to enhance its intrinsic activity. This work provides a general strategy that enables simultaneous defect engineering and electronic modulation of transition metal catalysts to achieve an enhancement in HER performance.

中文翻译：

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用于电催化析氢的富缺陷过渡金属纳米结构的化学能驱动锂化制备

过渡金属纳米结构被广泛认为是替代贵金属 Pt 用于水分解中析氢反应 (HER) 的重要催化剂。然而，通过一般的高温还原和烧结工艺难以获得尺寸均匀且超细的金属纳米晶粒。本文介绍了一种化学能驱动的锂化合成过渡金属纳米结构的新方法。利用室温下缓慢的结晶动力学，可以产生并保留更多的表面和边界缺陷，从而降低原子配位数并调整金属的电子结构和吸附自由能。其中获得的Ni纳米结构表现出优异的HER性能。此外，^-2在 127 mV 的低过电位下。高 HER 性能源于通过调整电子结构在 Ni 和 Co 之间形成良好的协同效应。密度泛函理论模拟证实，双金属镍钴具有较低的氢吸附吉布斯自由能，有利于提高其本征活性。这项工作提供了一种通用策略，可以同时对过渡金属催化剂进行缺陷工程和电子调制，从而提高 HER 性能。