Yuke's paper has been accepted for publication in Nature Communication. Congratulations!

This is a collaboration with Soochow University, University of Science and Technology of China,  and Institute of High Energy Physics, Chinese Academy of Sciences. 

Title: Promoting Nickel Oxidation State Transitions in Single-Layer NiFeB Hydroxide Nanosheets for Efficient Oxygen Evolution

Authors: Yuke Bai,† Yu Wu,† Xichen Zhou, Yifan Ye, Kaiqi Nie, Jiaou Wang, Miao Xie, Zhixue Zhang, Zhaojun Liu, Tao Cheng,* and Chuanbo Gao*

Link to the publisher: https://www.nature.com/articles/s41467-022-33846-0

Abstract: Promoting the formation of high-oxidation-state transition metal species in a hydroxide catalyst may improve its catalytic activity in the oxygen evolution reaction, which remains difficult to achieve with current synthetic strategies. Herein, we present a synthesis of single-layer NiFeB hydroxide nanosheets and demonstrate the efficacy of electron-deficient boron in promoting the formation of high-oxidation-state Ni for improved oxygen evolution activity. Raman spectroscopy, X-ray absorption spectroscopy, and electrochemical analyses show that incorporation of B into a NiFe hydroxide causes a cathodic shift of the Ni²⁺(OH)2 → Ni^3+δOOH transition potential. Density functional theory calculations suggest an elevated oxidation state for Ni and decreased energy barriers for the reaction with the NiFeB hydroxide catalyst. Consequently, a current density of 100 mA cm^–2 was achieved in 1 M KOH at an overpotential of 252 mV, placing it among the best Ni-based catalysts for this reaction. This work opens new opportunities in electronic engineering of metal hydroxides (or oxides) for efficient oxygen evolution in water-splitting applications.

文章解读：西安交大科研人员在电解水制氢关键催化材料方面取得新进展

为实现国家“双碳”目标，满足现代社会对于清洁能源的需求，寻求高效的清洁能源生产变得尤为重要。电解水制氢是绿氢制备最有前景的途径之一，是未来可再生能源工业链条上的重要环节。目前，电解水制氢仍存在较高的电耗成本，是该技术大规模工业应用所面临的主要难题。究其原因，电解水的阳极析氧反应（OER）是一个涉及四电子转移的迟滞的化学反应过程，通常需要施加较高的过电势以驱动反应的进行，从而造成严重的电能损耗。因此，发展高效的析氧反应催化剂是降低电解水制氢成本的重要途径。

过渡金属氢氧化物被认为是碱性条件下析氧反应最优的催化剂体系。在析氧反应中，过渡金属演化为高价物种，是OER的活性位点。然而，目前缺乏对于过渡金属高价物种形成过程的有效调控，成为该催化剂技术的瓶颈问题。针对这一问题，西安交通大学前沿院高传博教授课题组发展了基于硼元素（B）掺杂的镍（Ni）价态演化调控策略，利用硼元素固有的缺电子性，促进了镍中心失电子的价态演化过程，使高价活性物种能在低电势下形成，显著提升了镍铁氢氧化物催化剂的OER性能。拉曼光谱、X射线吸收光谱和电化学测试证实了硼元素在镍的价态演化过程中起到了关键作用。密度泛函理论计算证实了硼与镍之间的电子相互作用。基于该原理，该团队合成的NiFeB氢氧化物纳米片在252 mV过电势下即可达到100 mA cm−2的OER电流密度，显著优于迄今报道的大多数镍基催化剂的催化性能。这项研究为高效OER催化剂的设计和实现提供了理论指导，为电解水制氢的工业可行化提供了技术积累。

上述研究成果以《促进单层镍铁硼氢氧化物纳米片中镍的价态演化实现高效析氧性能》（Promoting nickel oxidation state transitions in single-layer NiFeB hydroxide nanosheets for efficient oxygen evolution）为题发表在《自然通讯》（Nature Communications）。