Understanding the role of the electrolyte composition in electrocatalysis: How electrolytes control the catalytic activity

最近，世界范围内的领先小组已经根据经验确定了许多系统，其中某些电解质组合物出乎意料地增加了电催化材料的总体活性。然而，对于为什么典型的惰性物质，如Li+、Na+或K+，可以增加活性，缺乏基本的理解。“正”电解质效应通常比通过优化表面电子结构和电极组成获得的效应更显著。不幸的是，目前在该领域的理解仍然没有达到稳定预测这种情况下的活动趋势的水平。在这个建议中，重点是设置在这样的电解质效应的系统调查。要详细说明的中心假设是，对于给定的电极结构和组成，双电层形成的所谓最大熵的电势主要是观察到的电解质影响的原因。重要的是要注意，最大熵的潜力应该与零电荷的潜力区分开来。最近的研究表明，在电极的稳定区域内，可能存在几个潜在的最大熵，也可能没有。这为探索提高电催化系统性能的方法开辟了新的自由度。现代技术，包括经典的电化学和拉曼方法和独特的激光诱导电流瞬态光谱，将被用来阐述一种能够解释和预测上述电解质效应的方法。与可再生氢燃料的产生和使用相关的反应（析氢、析氧和氧还原反应）将被用作模型过程。金属氧化物/氢氧化物电催化剂衍生于金属有机骨架（MOF），特别是衍生于表面安装的MOF（即，SURMOFs），以及单晶金属，金属合金电极，将被用作本研究中的模型表面，以阐述高效的电催化系统，并了解电解质组合物在增加活性中的作用。

Recently leading groups worldwide have empirically identified a number of systems where certain electrolyte compositions unexpectedly increase the overall activity of electrocatalytic materials. However, there is a severe lack of fundamental understanding of why typically inert species, like Li+, Na+, or K+, can increase the activity. The "positive" electrolyte effect is often even more pronounced than that obtained by optimizing the surface electronic structure and electrode composition. Unfortunately, the current understanding in the field is still not at the level to steadily predict the activity trends in this case. In this proposal, the focus is set on the systematic investigation of such electrolyte effects. The central hypothesis to elaborate on is that for a given electrode structure and composition, the so-called potential of maximum entropy of the formation of the electric double layer is primarily responsible for the observed electrolyte influence. It is important to note that the potential of maximum entropy should be distinguished from the potential of zero charge. There could be several potential maximum entropy or none within the stability region of electrodes, as was shown recently. This opens up a new degree of freedom to explore ways of increasing the performance of electrocatalytic systems. Modern techniques, including classical electrochemical and Raman methods and the unique laser-induced current transient spectroscopy, will be used to elaborate an approach capable of explaining and predicting the above-mentioned electrolyte effects. Reactions relevant to the generation and use of renewable hydrogen fuel (hydrogen evolution, oxygen evolution, and oxygen reduction reactions) will be used as the model processes. Metal oxide/hydroxide electrocatalysts derived metal-organic frameworks (MOFs), in particular, derived from surface-mounted MOFs (i.e., SURMOFs), as well as single crystal metal, metal-alloy electrodes, will be used as the model surfaces in this study to elaborate highly efficient electrocatalytic systems and understand the role of the electrolyte composition in the increased activity.