Highly Robust and Efficient Water Oxidation Catalysts based on Nanoscopic Metal Oxide Species (Polyoxometalates): from Fundamental Science to Devices

在这个SPP中，开发了光电解电池，收集阳光并使用该能量来分解水。水裂解发生在两个半反应中，即析氢和析氧反应（HER和OER）。每个电子过程只需要1.23 eV来分解水，高效的捕光材料将提供1.8 - 2.5 eV的电池电压。由于阻挡层与HER和OER相关，其抑制反应并显著降低总电池效率，因此重要的是开发高选择效率、低成本且没有环境问题的催化剂。本文提出了基于多氧酸盐（POMs）开发新型OER催化剂的设想。这些独特的金属氧化物簇介于溶剂化金属离子和扩展金属氧化物晶格之间，可用于掺入和设计具有不同拓扑结构的催化核心。目前的文献揭示了高量子效率的POM为基础的光催化水氧化系统的高达30%，在可见光区和营业额约450 h-1的频率。然而，我们相信，可以开发出更有效的Ru-POM催化剂以及基于更丰富和负担得起的金属（例如Mn、Co、Ni）的POM水氧化催化剂。除了它们的高效率之外，POM具有几个强的特征，即簇可以在中性以及低pH下操作，是热稳定的和氧化稳定的，可以包含成本效益和环境友好的元素，并且它们可以兼容地固定在半导体表面上。在这个提议中，我们提出开发高效的Ru POM催化剂以及探索基于较便宜金属的POM的潜力（Mn，Co，Ni）用于驱动OER。我们将合成并全面表征这些材料，测试它们在均相中的催化性能，最后将它们存款到TiO 2上以制备光电催化阳极。这些发展是实验和理论之间的密切合作，有四个相互关联的理论和实验研究包。

In this SPP, photoelectrolytic cells are developed that harvest sunlight and use that energy to split water. The water splitting occurs in two half-reactions, the hydrogen and the oxygen evolution reactions (HER and OER). Only 1.23 eV per electron process are necessary to split water, highly 2 efficient light-harvesting materials will deliver cell voltages of 1.8…2.5 eV, depending. As a barrier is associated to HER and OER that suppresses the reaction and considerably lowers the overall cell efficiency, it is important to develop catalysts of high selective efficiency, low cost, and without environmental issues. We propose to develop novel catalysts for the OER on the basis of polyoxometalates (POMs).The emerging class of nanoscopic POMs in the past three years revealed significant potential as water splitting catalysts. Ranging between solvated metal ions and extended metal oxide lattices, these unique metal-oxide clusters are available for incorporation and engineering of catalytic cores with varying topologies. Current literature reveals high quantum efficiency for POM based photocatalytic water oxidation systems of up to 30% in the visible light region and turnover frequencies of about 450 h-1. However we believe that even more efficient Ru-POM catalysts as well as POM water oxidation catalysts based on more abundant and affordable metals (e.g. Mn, Co, Ni) can be developed. Besides their high efficiency, POMs have several strong features, namely the clusters can operate in neutral as well as low pHs, are thermally and oxidatively stable, can incorporate cost efficient and environmentally friendly elements and they are compatible for immobilization on semiconducting surfaces.In this proposal we offer to develop highly efficient Ru POM catalysts as well as explore the potential of POMs based on the less expensive metals (Mn, Co, Ni) for driving the OER. We will synthesize and thoroughly characterize these materials, test their catalytic performance in homogeneous phase and finally deposit them to TiO2 in order to produce photoelectrocatalytic anodes. The developments are a close collaboration between experiment and theory, with four mutually interconnected theoretical and experimental research packages.