Probing the Interfacial behavior of nanostructured electrocatalysts for environmentally relevant catalytic systems

重要的可再生能源技术的发展和可行性与其相关催化材料的电化学性能密不可分。电催化剂的表面组成和原子结构对其催化活性和反应选择性等性能特征有重要影响。对催化过程的基本了解对社会的意义与寻找将电化学装置作为替代能源系统商业化所必需的新材料一样重要。在这两种情况下，电化学继续发挥着关键作用。在电活性材料上研究的各种催化过程中，二氧化碳还原反应(CRR)是一个与环境应用相关的过程，可以作为测试新电极的模型系统。拟议的研究计划侧重于启动对纳米结构合金、修饰表面和定义明确的表面上氧化还原过程的动力学和机理的研究，以阐明和理解电催化过程中涉及的界面和电化学现象(吸附现象、电沉积和成核)。我们建议选择性地对表面态进行修饰，以研究其在反应中间体和产物性质中的作用。通过适当选择电催化剂中参与金属的性质和化学计量比，可以设计出具有不同吸附能力、迁移率和结构几何形状的底物来抑制或控制副反应，从而提高工艺效率。该研究计划侧重于“系综效应”的作用和金属-电解液界面的性质，即对于CRR和ORR这两个相关的电化学反应。将使用室温离子液体等溶剂以及传统的水介质来探索新的二氧化碳转化系统。为了了解表面修饰和表面结构对(In)有机分子的电化学活性和选择性的影响，将使用在线电化学质谱学和旋转环盘电极作为辅助技术来研究反应机理和产物。原位X射线吸收光谱也将作为一种强有力的技术来研究所设计的电催化剂的表面。在技术上，这项研究的目的是提供结果，在短期或长期内，有助于更好地从根本上了解活性材料的双功能，并最终将导致改进的用于能源转换和环境应用的电催化剂。

Development and viability of important renewable energy technologies are inextricably linked to the electrochemical performance of their related catalytical materials. The composition of an electrocatalyst's surface and its atomic structure have a crucial influence on its performance characteristics, i.e. its catalytic activity and reaction selectivity. The fundamental understanding of catalytic processes is as meaningful for society as the search for new materials necessary for the commercialization of electrochemical device as alternative energy systems. In both cases, electrochemistry continues to play a pivotal role. Of various catalytic processes examined on electroactive materials, carbon dioxide reduction reaction (CRR) is a relevant processes with environmental applications and can be excellent candidate to be used as model systems for testing new electrodes. The proposed research program is focus on initiating a study of the kinetics and mechanism of those redox processes at nanostructured alloys, modified surfaces and well-defined surfaces for the elucidation and the understanding of the interfacial and electrochemical phenomena involved in electrocatalytic processes (adsorption phenomena, electrodeposition and nucleation). We proposed to modify the surface state selectively to study its role in the nature of the reaction intermediates and products. By the proper choice of the nature and stoechiometry of the participant metal in the electrocatalysts, it is possible to design substrate with various adsorption capability, mobility and structural geometry to inhibit or control the side reactions and to enhance the process efficiency. The research program is focusing on the role of the “ensemble-effect” and the nature of the interface metal-electrolyte, namely for CRR and ORR, two relevant electrochemical reactions. New CO2 conversion systems will be explore with solvents such as room temperature ionic liquids as well as with conventional aqueous media. In order to understand the impact of surface modifications and surface structure on the electrochemical activity and selectivity of (in)organic molecules, the reaction mechanisms and products will be investigate using on-line Electrochemical Mass Spectrometry and Rotating ring-disk Electrodes as complementary techniques. In-situ X-ray Absorption Spectroscopy will also be explore as a powerful technique to study surfaces of the designed electrocatalysts . Technologically, this research aims to provide results that will, on the short or long term, leads towards a better fundamental understanding of bifunctionnality of active materials and, ultimately, should lead to improved electrocatalysts for energy conversion and environmental applications.