Spectroelectrochemical characterization of heterogeneous electrocatalyst surfaces

电催化还原二氧化碳的反应引起了几代科学家的兴趣，目前在工业界、政府和学术界引起了极大的关注。现代人们对电化学还原二氧化碳的兴趣很大程度上源于这样一个事实，即当与水氧化相结合时，这种反应提供了一种可行的方法来产生可持续的全球碳循环。这样的循环将减轻人为二氧化碳排放的影响，同时为合成从碳氢化合物燃料到商品化学品等有用的化学品提供一种非化石燃料原料。然而，尽管经过几十年的研究，商业/工业兴趣有限的2-电子还原产品仍然是唯一能够以可接受的选择性可靠地合成的产品。拟议的研究计划寻求建立一个长期的战略重点，利用最先进的光谱电化学技术进行机理研究，以便能够合理设计能够选择性地将二氧化碳转化为高价值、商业相关化学品的催化剂。*许多报告描述了电化学反应系统的变化，使二氧化碳能够转化为所需碳氢化合物的混合物。使碳氢化合物合成成为可能的策略包括电极组成旋转、电极表面工程和在电解液中添加辅助催化剂。然而，这些方法往往会产生不同的化学产品混合物，而且选择性地合成所需产品的能力仍然难以捉摸。这项研究计划将利用光谱仪器和技术的最新进展，在操作条件下(即原位光谱电化学)获取多相电催化剂表面的结构信息。在操作过程中进行的光谱电化学测量将能够监测电极表面/附近的化学变化，从而产生关于反应机理的信息。重复对整个体系中战略性的、系统的组分变化的实验，例如添加一系列助催化剂，将揭示反应组分对反应机理的影响。将对整个研究计划产生的数据库进行比较分析，以揭示设计原则，使电催化剂的合理设计和反应系统的改进，以提高电催化二氧化碳还原的选择性。

The electrocatalytic reduction of CO2 is a reaction that has captured the interest of generations of scientists and currently commands significant attention in industrial, government and academic circles. Much of the modern interest in electrochemical reduction of CO2 originates from the fact that, when coupled with water oxidation, this reaction provides a viable means to generate a sustainable, global carbon cycle. Such a cycle would act to mitigate the impact of anthropogenic CO2 emissions while providing a non-fossil fuel feedstock for synthesizing useful chemicals, ranging from hydrocarbon fuels to commodity chemicals. Despite decades of research, however, 2-electron reduction products with limited commercial/industrial interest remain the only products that can be reliably synthesized with acceptable selectivity. The proposed research program seeks to establish a long-term, strategic focus that will utilize state-of-the-art spectroelectrochemical techniques to perform mechanistic studies to enable the rational design of catalysts capable of selective conversion of CO2 into high value, commercially relevant chemicals. ******Numerous reports have described changes to the electrochemical reaction system that enable conversion of CO2 into mixtures of desirable hydrocarbon products. Strategies that have enabled hydrocarbon synthesis include electrode composition turning, electrode surface engineering, and addition of co-catalysts to the electrolyte solution. These approaches tend to produce a diverse mixture of chemical products, however, and the ability to selectively synthesize desirable products remains elusive. This research program will capitalize on recent advances in spectroscopic instrumentation and techniques to acquire structural information on heterogeneous electrocatalyst surfaces under operational conditions (i.e. in-situ spectroelectrochemistry). Spectroelectrochemical measurements performed during operation will enable changes in chemistry at/near the electrode surface to be monitored, yielding information regarding reaction mechanisms. Repetition of the experiments upon strategic, systematic variation of components in the overall system, upon addition of a series of co-catalysts for example, will reveal the impact of the reaction component on the reaction mechanism. The library of data that will be generated throughout this research program will be comparatively analyzed to reveal design principles enabling the rational design of electrocatalysts and reaction system modifications to improve the selectivity of electrocatalytic CO2 reduction.