Spectroelectrochemical characterization of heterogeneous electrocatalyst surfaces

CO2的电催化还原是一个引起几代科学家兴趣的反应，目前在工业界、政府和学术界引起了极大的关注。现代对CO2电化学还原的兴趣主要源于这样一个事实，即当与水氧化反应结合时，该反应提供了一种可行的方法来产生可持续的全球碳循环。这种循环将有助于减轻人为二氧化碳排放的影响，同时为合成从碳氢燃料到商品化学品等有用化学品提供非矿物燃料原料。然而，尽管进行了数十年的研究，但具有有限商业/工业利益的2-电子还原产物仍然是唯一可以可靠地以可接受的选择性合成的产物。拟议的研究计划旨在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，以合理设计能够将CO2选择性转化为高价值的商业相关化学品的催化剂。许多报道已经描述了电化学反应系统的改变，其能够将CO2转化为所需烃产物的混合物。使烃合成成为可能的策略包括电极组合物转向、电极表面工程和向电解质溶液中添加助催化剂。然而，这些方法倾向于产生多种化学产品的混合物，并且选择性地合成所需产品的能力仍然是难以捉摸的。该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）获得非均相电催化剂表面的结构信息。在操作期间进行的光谱电化学测量将使得能够监测电极表面处/附近的化学变化，从而产生关于反应机制的信息。在整个系统中组分的策略性、系统性变化上重复实验，例如在添加一系列助催化剂时，将揭示反应组分对反应机理的影响。将在整个研究计划中产生的数据库将进行比较分析，以揭示设计原则，使电催化剂和反应系统的修改，以提高电催化CO2还原的选择性的合理设计。

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.