Bharatbhai Joshi Ankitkumar, Roy Soumalya, Dey Atanu, Aziz Tarik, Tothadi Srinu, Bandhyopadhyay Mahuya, Giri Soumen, Das Sourav
Department of Basic Sciences, Chemistry Discipline Institute of Infrastructure Technology Research and Management, Near Khokhra Circle Maninagar East, Ahmedabad, Gujarat, 380026, India.
Department of Chemistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 61186, Republic of Korea.
Small. 2025 Jul;21(29):e2504175. doi: 10.1002/smll.202504175. Epub 2025 May 12.
The oxygen evolution reaction (OER) is integral to electrochemical energy systems; however, its intrinsic sluggish kinetics necessitate the design of high-performance electrocatalysts to minimize overpotential, enhance the durability, and optimize the efficiency. Significant efforts have been dedicated to developing OER catalysts based on earth-abundant transition-metal complexes. Here, the efficacy of a tetranuclear cubane-cored Ni(II) complex, [Ni₄(LH)₄(MeOH)]·CHCl₃ (1), in OER is demonstrated. The complex is synthesized using a tetradentate Schiff-base ligand, [2-{(E)-(2-hydroxyphenylimino)methyl)-6-(hydroxymethyl)-4-methylphenol}], and characterized by single-crystal X-ray diffraction. The redox properties of complex 1 are evaluated by cyclic voltammetry in the solid state, which emphasize the quasireversible oxidation state of the Ni(II) metal center. The complex 1 is immobilized on activated carbon cloth (CC), referred as CC-1, which demonstrates efficient OER catalysis, subsequently activating to form the Ni(O)OH catalyst. The postreaction analysis including UV-vis, FTIR, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy confirm the stability of molecular complex 1. The results demonstrate efficient OER catalysis with a low overpotential of 330 mV versus reversible hydrogen electrode and a Tafel slope of 64 mV dec, confirming an effective OER catalyst in alkaline medium with a deep understanding of the core reaction mechanisms.
析氧反应（OER）是电化学能量系统不可或缺的一部分；然而，其固有的缓慢动力学需要设计高性能的电催化剂，以最小化过电位、提高耐久性并优化效率。人们已经付出了巨大努力来开发基于储量丰富的过渡金属配合物的OER催化剂。在此，展示了一种四核立方烷核Ni（II）配合物[Ni₄（LH）₄（MeOH）]·CHCl₃（1）在OER中的功效。该配合物使用四齿席夫碱配体[2-{（E）-（2-羟基苯基亚氨基）甲基}-6-（羟甲基）-4-甲基苯酚]合成，并通过单晶X射线衍射进行表征。配合物1的氧化还原性质通过固态循环伏安法进行评估，这突出了Ni（II）金属中心的准可逆氧化态。配合物1固定在活性炭布（CC）上，称为CC-1，它表现出高效的OER催化作用，随后活化形成Ni（O）OH催化剂。包括紫外可见光谱、傅里叶变换红外光谱、扫描电子显微镜-能量色散X射线光谱和X射线光电子能谱在内的反应后分析证实了分子配合物1的稳定性。结果表明，相对于可逆氢电极，该配合物在330 mV的低过电位和64 mV dec的塔菲尔斜率下具有高效的OER催化作用，证实了其在碱性介质中是一种有效的OER催化剂，且对核心反应机理有深入理解。
