Photochemical H 2 Evolution from Bis(diphosphine)nickel Hydrides Enables Low-Overpotential Electrocatalysis
Photochemical H 2 Evolution from Bis(diphosphine)nickel Hydrides Enables Low-Overpotential Electrocatalysis
复制标题
双(二膦)镍氢化物光化学演化H 2 可实现低过电势电催化
DOI：
10.1021/jacs.1c10628
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发表时间：
2021
影响因子：
15
通讯作者：
Miller, Alexander J.
中科院分区：
文献类型：
--
作者：
Stratakes, Bethany M.;Wells, Kaylee A.;Kurtz, Daniel A.;Castellano, Felix N.;Miller, Alexander J.
既能捕光又能形成新化学键的分子有望在太阳能燃料的产生中应用，但这样的第一排过渡金属光电催化剂是缺乏的。在这里，我们报道了镍光电催化剂析氢，利用可见光驱动的光化学析氢双(双膦)氢化镍络合物。一系列的实验和理论分析，包括时间分辨光谱和连续辐照量子产额测量，导致了提出的氢的演化机制，涉及到一个短暂的单重态激发态，经历了Ni-H键的均裂。热力学分析为理解和预测3D过渡金属基催化剂的光电催化析氢行为提供了基础。特别值得注意的是电化学过电位的巨大变化：在黑暗中，镍络合物需要强酸，因此需要高过电位用于电催化；但在光照下，在相同应用电位下使用较弱的酸导致电化学过电位提高500 mV以上。对第一排过渡金属氢化物光化学的新见解使光电催化在没有电化学过电位(热力学电位或0 mV过电位)下析氢成为可能。这种催化体系不需要牺牲化学还原剂或捕光半导体材料，产生氢气的速度类似于附着在硅上的分子催化剂。
Molecules capable of both harvesting light and forming new chemical bonds hold promise for applications in the generation of solar fuels, but such first-row transition metal photoelectrocatalysts are lacking. Here we report nickel photoelectrocatalysts for H2evolution, leveraging visible-light-driven photochemical H2evolution from bis(diphosphine)nickel hydride complexes. A suite of experimental and theoretical analyses, including time-resolved spectroscopy and continuous irradiation quantum yield measurements, led to a proposed mechanism of H2evolution involving a short-lived singlet excited state that undergoes homolysis of the Ni–H bond. Thermodynamic analyses provide a basis for understanding and predicting the observed photoelectrocatalytic H2evolution by a 3d transition metal based catalyst. Of particular note is the dramatic change in the electrochemical overpotential: in the dark, the nickel complexes require strong acids and therefore high overpotentials for electrocatalysis; but under illumination, the use of weaker acids at the same applied potential results in a more than 500 mV improvement in electrochemical overpotential. New insight into first-row transition metal hydride photochemistry thus enables photoelectrocatalytic H2evolution without electrochemical overpotential (at the thermodynamic potential or 0 mV overpotential). This catalyst system does not require sacrificial chemical reductants or light-harvesting semiconductor materials and produces H2at rates similar to molecular catalysts attached to silicon.