Low-Coordinate 3d Metal Complexes as Alternatives to Platinum Group Metals for Hydrogen Evolution Reaction

通过析氢反应（HER）减少水来生产氢气是一种有前途的可持续替代碳氢化合物原料的方法。目前最先进的技术使用铂，因为它在低过电位和高周转频率下工作。然而，铂的低丰度（地壳中37 ppb）导致高经济和环境成本，其高毒性导致生产大量废物流。使用具有低成本、高自然丰度、均匀全球分布和低毒性的富土金属的替代催化剂对于提高该反应的可持续性至关重要，因此可以作为氢的来源。以钴为特征的催化剂是该反应的优秀候选者，其中HER进化反应的机理研究已经确定了关键过程，例如CoI到CoIII-H的质子化是形成H-H键的关键中间体。该项目将开发一系列钴(I)有机金属配合物作为单金属HER催化剂，其中金属中心使用高度立体阻碍配体稳定。尽管这些独特的配合物具有良好的氧化还原化学和底物结合环境，但从未对HER化学进行过研究。钴(I)化合物将被研究其氧化还原化学和对酸的敏感性，以及它们在HER条件下的电化学响应。从这项研究中获得的信息将使我们能够开发配体设计，以改善反应。该学生将受益于合成化学技术（如有机金属化学、光谱学、晶体学和动力学研究）和电化学方面的培训。通过光谱、结构和动力学研究来确定反应机制，可以优化反应。我们预计这样的研究也将允许改善反应条件和氢释放所需的催化剂负载。可交付成果- HER的新催化剂-对这些反应的机理理解，以及HER中催化剂/配体设计的信息- HER反应的优化

The production of hydrogen through the reduction of water via the Hydrogen Evolution Reaction (HER) is promising sustainable alternative to the use of hydrocarbon feedstocks. The current state of the art uses platinum as it operates at low overpotential with high turnover frequencies. However, the low abundance of platinum (37 ppb in the Earth's crust) leads to high economic and environmental cost, and its high toxicity leads to the production significant waste streams. The use of alternative catalysts featuring earth abundant metals that exhibit low cost, high natural abundance, uniform global distribution and low toxicity is essential to improving the sustainability of this reaction, and therefore as a source of hydrogen. Catalysts featuring cobalt are excellent candidates for this reaction, where mechanistic studies of the HER evolution reaction have identified key processes such as the protonation of CoI to CoIII-H species as key intermediates in the formation of H-H bonds.This project will develop a range of cobalt(I) organometallic complexes as single metal HER catalysts, where the metal centre is stabilised using highly sterically encumbering ligands. These unique complexes have never been investigated for HER chemistry, despite their favourable redox chemistry and substrate binding environment. The cobalt(I) compounds will be investigated for their redox chemistry and sensitivity to acid, along with their electrochemical response in the HER conditions. Information gained from this investigation will allow us to develop the ligand design in order to improve the reaction. The student will benefit from training in synthetic chemical techniques (e.g. organometallic chemistry, spectroscopy, crystallography and kinetic investigations) and electrochemistry. Determination of reaction mechanisms through spectroscopic, structural and kinetic investigations allows the optimisation of the reactions. We anticipate that such investigations will also allow improvements in the reaction conditions and catalyst loadings required for hydrogen release.Deliverables-New earth abundant catalysts for HER-Mechanistic understanding for these reactions, and information to inform catalyst/ligand design in HER-Optimisation of HER reactions