Electrocatalytic H2 Evolution by the Co‐Mabiq Complex Requires Tempering of the Redox‐Active Ligand
Electrocatalytic H2 Evolution by the Co‐Mabiq Complex Requires Tempering of the Redox‐Active Ligand
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DOI：
10.1002/cctc.201900953
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发表时间：
2019-08
期刊：
影响因子：
4.5
通讯作者：
G. C. Tok;Anna T. S. Freiberg;H. Gasteiger;Corinna R. Hess
中科院分区：
文献类型：
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作者：
G. C. Tok;Anna T. S. Freiberg;H. Gasteiger;Corinna R. Hess
氢气是一种很有前途的可持续能源转换和储存燃料。开发有效的地球富氢析氢催化剂是推进氢基技术不可或缺的一部分。分子络合物的放氢通常涉及金属氢化物中间体的形成。最近，氧化还原活性配体的使用已经成为电子和质子存储的替代策略。在本文中，我们研究了含有氧化还原活性大环配体的[CoII（Mabiq）（THF）]（PF 6）（CoMbq）在酸性有机介质中的电催化行为（使用帕拉氰基苯胺（pCA）作为质子源）。循环伏安法（CV）和旋转环盘电极（RRDE）伏安法证明了导致形成质子化的双电子还原中间体的预催化过程。该物种在-1.1 VFc的负电位下放出H2，经在线电化学质谱法（OEMS）证实。OEMS结果进一步揭示了催化剂失活途径。电化学数据表明氧化还原活性Mabiq配体参与析氢反应（HER），这对在电催化复合物中使用此类支架具有影响。
H2 is a promising fuel for sustainable energy conversion and storage. The development of effective earth abundant H2 evolution catalysts is integral to advancing hydrogen‐based technologies. H2 evolution by molecular complexes classically involves the formation of metal hydride intermediates. Recently, the use of redox‐active ligands has emerged as an alternate strategy for electron and proton storage. Herein, we examine the electrocatalytic behavior of [CoII(Mabiq)(THF)](PF6) (CoMbq), containing a redox‐active macrocyclic ligand, in acidic, organic media (using para‐cyanoanilinium (pCA) as the proton source). Cyclic voltammetry (CV) and Rotating Ring Disk Electrode (RRDE) voltammetry evidence a pre‐catalytic process that leads to the formation of a protonated, two‐electron reduced intermediate. This species evolves H2 at potentials negative of −1.1 VFc, as confirmed by On‐line Electrochemical Mass Spectrometry (OEMS). OEMS results further reveal a catalyst deactivation pathway. The electrochemical data denote the involvement of the redox‐active Mabiq ligand in the hydrogen evolution reaction (HER), with implications for the use of such scaffolds in electrocatalytic complexes.