Elucidating the role of catalyst-support interaction on the activity and stability of water splitting catalysts

本提案探讨了催化剂和固体载体在带电固液界面上的化学相互作用的性质和影响。催化剂|支持系统包括非贵金属催化剂，作为析氢反应（HER）和析氧反应（OER）的活性位点。该项目将系统地研究与光电化学器件相关的催化剂-载体相互作用，并建立埋藏的催化剂-载体界面的几何和电子结构与其在电极-电解质界面产生的光电化学活性和稳定性之间的关系。为了达到这一目标，一个主要的重点是在基本水平上理解不同类型的催化剂|支撑系统的电子和结构相互作用的程度。例如，吸附相互作用与共价附着的活性位点相互作用（通过不同的连接基团）将得出结论，在多大程度上需要额外的功能化和连接步骤来获得活性和稳定的催化剂|支持系统。研究了nife基氧化物和（氧）氢氧化物（NiFeOx）作为OER催化剂和具有分子MeN4中心的HER催化剂。基于标准的结构和电化学表征，将选择不同的体系进行更详细的表征。作为先进的表征技术，不同的方法被应用于原位和操作，如x射线吸收光谱（XAS）和Mössbauer光谱。结合环境压力对所选样品的x射线光电子能谱（XPS）和不同气体气氛和电解质的存在对界面进行逐步分析，可以得出催化剂|支撑系统的电子和结构相互作用的改变程度。虽然主要关注的是催化剂|支持在模型电极上的相互作用，但实际设备中的相互依赖性也将得到解决。因此，最有前途的催化剂体系将在相关半导体（SC）或SC +钝化层上进行研究。因此，与具有一个固体-固体界面的模型电极相反，这些设备结合了所有的界面和相关的相互依赖性。因此，所获得的结果应该能够对未来基于知识的功能复合结构设计工作进行有用的预测，这些功能复合结构需要在后续项目中集成到设备中。虽然本项目侧重于基础方面（但与相关支持密切相关），但在未来的工作中，还将进一步优化催化剂或应用新的催化系统。本项目所获得的结果可能对其他使用强电子耦合来协调功能单元的催化体系或结构也具有重要意义。

This proposal explores the nature and impact of chemical interactions between a catalyst and a solid support at electrified solid-liquid interfaces. Catalyst|support systems addressed here comprise non-precious metal catalysts as active sites for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The project will systematically study catalyst-support interactions using selected supports relevant to photoelectrochemical devices and establish relations between the geometric and electronic structure of the buried catalyst-support interface and its resulting photoelectrochemical activity and stability at the electrode-electrolyte interface.In order to reach this goal, a main focus is directed to understand the extent of electronic and structural interaction for different types of catalyst|support systems on a fundamental level. For instance, adsorptive interaction versus covalently attached active site interaction (via different linkage groups) will allow conclusions as to what extent the additional steps of functionalization and linkage are indeed required to obtain an active and stable catalyst|support system.As catalysts NiFe-based oxides and (oxy)hydroxides (NiFeOx) are investigated for the OER and catalysts with molecular MeN4 centers for the HER. Based on standard structural and electrochemical characterization different systems will be selected for a more detailed characterization.As advanced characterization techniques different methods are applied in-situ and operando as X-ray absorption spectroscopy (XAS) and Mössbauer spectroscopy. The stepwise analysis of the interface with respect to the presence of different gas atmospheres and electrolytes in combination with (ambient pressure) X-ray photoelectron spectroscopy (XPS) of selected samples will enable conclusions to what extent the electronic and structural interaction of the catalyst|support system are changed.While the main focus is directed on the catalyst|support interaction on model electrodes, the interdependence in real devices will be addressed as well. Therefore, the most promising catalyst systems will be investigated on the related semiconductors (SC) or SC + passivation layer. Thus, in contrast to the model electrode with one solid-solid interface, these devices combine all the interfaces and related interdependence.As a consequence, the acquired results should enable useful predictions for future works on a knowledge-based design of such functional composite structures that need to be integrated in devices within the follow-up project. While this project focusses on the fundamental aspects (but in close relation to relevant supports), in future work also the further optimization of catalysts or application of new catalytic systems will be addressed.The results obtained in this project might be of importance also for other catalytic systems or structures that uses strong electronic coupling for coordination of functional units.