Photocatalytic Hydrogen Production with A Molecular Cobalt Complex in Alkaline Aqueous Solutions
Photocatalytic Hydrogen Production with A Molecular Cobalt Complex in Alkaline Aqueous Solutions
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DOI：
10.1021/jacs.3c12928
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发表时间：
2024-03-26
影响因子：
15
通讯作者：
Zhao，Xuan
中科院分区：
文献类型：
--
作者：
Wang，Ping;Le，Nghia;Zhao，Xuan
碱性溶液对水的氧化在热力学上是有利的，这表明需要开发能够在碱性水溶液中发挥作用的析氢反应(HER)催化剂，以便整个水分解中的两个半反应都可以在相互兼容的溶液中发生。尽管HER主要在酸性溶液中被报道，在混合有机水溶液中的碱性PHS中也有少数被报道，但在纯碱性水溶液中由分子金属络合物催化的可见光驱动的HER在很大程度上仍未被探索。在此，我们报道了一种新的具有四吡啶配体的钴配合物，它在pH为9.0的纯水溶液中催化光解HER，转化率高达218 000。密度泛函理论(DFT)计算表明，CoII-H物种的质子化生成氢是一个改进的电子转移(E)-质子转移(C)-电子转移(E)-质子转移(C)(MOD-ECEC)途径。由于配体骨架结构的细微变化而产生的显著催化活性突出了在分子催化剂设计中研究结构-功能关系的重要性。我们目前的工作极大地推动了可见光分子金属催化剂的开发，使她在更具挑战性的碱性水溶液中驱动她，这在太阳能驱动的水分离系统中具有很大的前景。
The thermodynamic favorability of an alkaline solution for the oxidation of water suggests the need for developing hydrogen evolution reaction (HER) catalysts that can function in basic aqueous solutions so that both of the half reactions in overall water splitting can occur in mutually compatible solutions. Although photocatalytic HERs have been reported mostly in acidic solutions and a few at basic pHs in mixed organic aqueous solutions, visible-light driven HER catalyzed by molecular metal complexes in purely alkaline aqueous solutions remains largely unexplored. Here, we report a new cobalt complex with a tetrapyridylamine ligand that catalyzes photolytic HER with turnover number up to 218 000 in purely aqueous solutions at pH 9.0. Density functional theory (DFT) calculations suggested a modified electron transfer (E)–proton transfer (C)–electron transfer (E)–proton transfer (C) (mod-ECEC) pathway for hydrogen production from the protonation of CoII–H species. The remarkable catalytic activity resulting from subtle structural changes of the ligand scaffold highlights the importance of studying structure–function relationships in molecular catalyst design. Our present work significantly advances the development of a molecular metal catalyst for visible-light driven HER in more challenging alkaline aqueous solutions that holds substantial promise in solar-driven water-splitting systems.