Nanostructured mixed metal oxides for the electrocatalytic oxidation of water

光阳极上的析氧反应（OER）是高效直接光驱动水裂解的关键步骤。为了促进该反应，OER电催化剂是必不可少的。然而，由于大的动力学过电位、腐蚀性降解和当今Ru-Ir OER催化剂不可持续的珍贵性质而导致的低反应性仍然是水光电解的关键障碍。此外，对活性中间体和活性位点的性质的分子见解仍然有限。在SPP 1613内的这个合作项目的第一个资助期内，我们已经证明，基于IrNix合金和耐腐蚀导电氧化物的脱合金金属氧化物混合核壳纳米颗粒构成了高度稳定的电催化剂，用于水的电催化氧化，具有前所未有的法拉第和贵金属质量效率。在第二个资助期，我们将工作扩展到4个工作包中的4个具体目标。基于我们的外部合作伙伴的DFT计算，Ir氧化物OER催化剂的活性可以通过将第二种金属引入催化剂表面来提高。我们将探索替代非贵金属对金属氧化物混合核壳方法中催化剂活性和稳定性的影响。此外，一个基本的理解的OER的IrMOx和它们的降解机制的基本反应机制将获得通过使用电化学动力学分析结合原位光谱信息从XPS，振动光谱，环境SEM和监测潜在的金属溶解速率。此外，将研究与实际PEC电池设计相关的两个固体/固体界面（即活性催化剂/载体和载体/PEC-基材界面）的结构和化学状态，并基于上述知识和我们的OER催化剂，将与SPP 1613中的其他项目一起制造高效稳定的PEC电池。

The oxygen evolution reaction (OER) on photoanodes is a pivotal step for efficient direct light-driven water splitting. To facilitate this reaction, OER electrocatalysts are indispensable. Low reactivity due to large kinetic overpotentials, corrosive degradation, and the unsustainably precious nature of todays Ru-Ir OER catalysts, however, have remained key barriers to water photoelectrolysis. Also, molecular insights into the reactive intermediates and the nature of the active site are still limited. In the first funding period of this collaborative project within the SPP 1613 we have demonstrated that dealloyed metal-oxide hybrid core-shell nanoparticles based on IrNix alloys and supported on corrosion-resistant conductive oxides constitute highly stable electrocatalysts for the electrocatalytic oxidation of water with unprecedented faradaic and noble metal mass efficiency. For the second funding period we extend our work addressing 4 specific objectives in 4 work packages. Based on DFT calculations of our external collaborating partner, the activity of Ir-oxide OER catalysts can be elevated by incorporating a second metal into the catalyst surface. We will explore the effect of alternative non-precious metals on catalyst activity and stability within the metal-oxide hybrid core-shell approach. Furthermore, a fundamental understanding of the underlying reaction mechanism of the OER of IrMOx and their degradation mechanism will be obtained by using electrochemical kinetic analyses combined with in situ spectroscopic information from XPS, vibrational spectroscopy, environmental SEM and monitoring the rate of potential metal dissolution. In addition, the structure and chemical states of the two solid/solid interfaces relevant for practical PEC cell designs (i.e. the active catalyst/support and support/ PEC-substrate interface) will be investigated and based on the above knowledge and our OER catalyst efficient and stable PEC cells will be fabricated with other projects within SPP 1613.