Nanostructured mixed metal oxides for the electrocatalytic oxidation of water

光阳极上的析氧反应（OER）是实现高效直接光驱动水分解的关键步骤。为了促进这种反应，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，低反应性仍然是水光电解的主要障碍。此外，对反应中间体和活性位点性质的分子见解仍然有限。在spp1613合作项目的第一个资助期，我们已经证明了基于IrNix合金的合金金属氧化物杂化核壳纳米颗粒，并在耐腐蚀的导电氧化物上支撑，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。在第二个供资期，我们扩展了我们的工作，以解决4个工作包中的4个具体目标。根据我们外部合作伙伴的DFT计算，通过在催化剂表面加入第二种金属，可以提高ir -氧化物OER催化剂的活性。我们将在金属-氧化物杂化核-壳方法中探索替代非贵金属对催化剂活性和稳定性的影响。此外，通过电化学动力学分析，结合XPS、振动光谱、环境扫描电镜等原位光谱信息，以及对潜在金属溶解速率的监测，将对IrMOx OER的潜在反应机理及其降解机理有一个基本的了解。此外，将研究与实际PEC电池设计相关的两个固体/固体界面的结构和化学状态（即活性催化剂/载体和载体/ PEC-衬底界面），并基于上述知识和我们的OER催化剂高效和稳定的PEC电池将与spp1613的其他项目一起制造。

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.