Theoretical Investigation of Photo-Electro-Catalysis Beyond Proton-Coupled Electron Transfer

对于工业上可行的（光）电催化剂的设计和优化，例如用于水氧化，原子理解以及因此对各个反应步骤的越来越多的理论模拟至关重要。基于相对简单的考虑，理论筛选结果有助于为找到越来越有效的催化剂铺平道路，但也指出了金属催化剂可达到的效率的极限。超越这些的一种方法是寻找其他类别的材料，如氧化物，硫化物和氮化物。在那里，作为效率极限基础的比例关系一般不成立。另一方面，电化学表面反应研究中常用的许多假设也不成立。例如在氧化物中，已知可能的带电缺陷在反应性中起关键作用。此外，在半导体中，电化学反应步骤不一定必须经由质子耦合电子转移（PCET）通过中性中间体进行。我们建议开发一个模拟协议，基于固态和液体嵌入技术，量身定制，以解决这两个关键问题。由于嵌入，我们将能够研究PCET以外的反应途径，包括带电中间体及其与带电缺陷的相互作用。我们将首先应用这个一般协议来研究（缺陷）原型TiO 2（110）表面上的水裂解，相对于反应途径无偏。

For the design and optimisation of industrially viable (photo-) electrocatalysts, e.g. for water oxidation, the atomistic understanding and therefore more and more theoretical simulation of individual reaction steps is of vital importance. Based on relatively simple considerations theoretical screening results helped pave the way to find more and more efficient catalysts, yet also pointed out ultimate limits of the efficiency reachable with metallic catalysts. One way to go beyond these is to look to other classes of materials such as oxides, sulfides and nitrides. There, the scaling relations underlying the efficiency limits do not generally hold. On the other hand, many of the assumptions commonly employed in the study of electrochemical surface reactions do not hold either. For example in oxides, possibly charged defects are known to play a key role in the reactivity. Also, in semi-conductors electrochemical reaction steps do not necessarily have to proceed through neutral intermediates via proton-coupled electron transfer (PCET). We propose to develop a simulation protocol, based on solid-state and liquid embedding techniques, tailored to address these two key issues. Due to the embedding, we will be able to study reaction pathways beyond PCET, including charged intermediates and their interplay with charged defects. We will apply this general protocol first to study water splitting on the (defected) prototypical TiO2 (110) surface, unbiased with respect to the reaction pathway.