Surface and Microfluidic Electrochemistry

表面和微流体电化学

• 批准号: RGPIN-2017-04045
• 负责人: Harrington, David
• 金额: $ 1.6万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=747890
• 关键词: Surface; Microfluidic; Electrochemistry

The proposed electrochemical research is directed to the understanding of the details of electrocatalytic reactions of small organic molecules at noble metal electrodes. Oxidation of small (liquid) organic molecules to CO2 is the basis for direct liquid fuel cells (DLFCs). Reduction of CO2 to small organic molecules can replace fossil fuel routes to these molecules, and the combination of DLFCs with CO2 reduction is one way forward to a sustainable carbon neutral chemical economy. These reactions are complex multistep reactions, which generally involve many surface species and solution intermediates, and perfect selectivity to the desired product is not readily achieved. To optimize selectivity requires detailed study of the nature of these species and the kinetics of the transformations. The approach is to understand a few model electrocatalytic processes and find information that is predictive for related catalysts or reactions, rather than to find new catalysts through empirical searches. A combination of electrochemical, microfluidic and spectroscopic methods will be used to elucidate the individual steps in these reactions. In particular new combinations of these methods that look at these transformations in real time will be pursued. Recently, examples have been found where the selectivity can be dramatically changed by the local conditions, such as the local pH near the surface or the surface morphology. To understand these phenomena, the detailed way in which the mass transport in solution is coupled to the surface reactions must be understood. An important tool to understand mass transport effects is in microfluidic electrochemical devices, in which flow past a reacting electrode sweeps intermediates and products downstream to a detector. New electrochemical detection methods will be developed. We will also add downstream spectroscopic methods, including Raman (collaboration with Brolo, UVic) and DEMS (collaboration with Seland and Sunde, NTNU, Norway). We will use fast electrochemical methods to understand the kinetics, including those based on dynamic electrochemical impedance spectroscopy, which can capture impedance spectra as a function of time. We will extend the capabilities of this method and of supporting theory. The thin oxide films on Pt and Pd electrodes typically inhibit electrocatalytic activity. Despite study for many years, the nature of the oxide, how it grows and how it influences electrocatalysis is poorly understood. In collaboration with Drnec (European Synchrotron Radiation Facility) and Magnussen (Kiel), we will apply synchrotron surface X-ray diffraction to study the structure of the oxide and the kinetics of its formation. The combined use of multiple electrochemical and spectroscopic methods will give a comprehensive picture about the electrocatalytic reaction mechanisms of selected organic oxidation and CO2 reduction reactions.

所提出的电化学研究是针对小有机分子在贵金属电极上的电催化反应的细节的理解。将小（液体）有机分子氧化成CO2是直接液体燃料电池（DLFC）的基础。将CO2还原为小的有机分子可以取代化石燃料的途径来获得这些分子，而DLFC与CO2还原的结合是实现可持续碳中性化学经济的一种方法。 这些反应是复杂的多步反应，通常涉及许多表面物种和溶液中间体，并且不容易实现对所需产物的完美选择性。为了优化选择性，需要详细研究这些物种的性质和转化的动力学。该方法是了解一些模型电催化过程，并找到相关催化剂或反应的预测信息，而不是通过经验搜索找到新的催化剂。 电化学，微流体和光谱方法的组合将用于阐明这些反应中的各个步骤。特别是，将寻求这些方法的新组合，这些方法在真实的时间内观察这些变换。最近，已经发现的例子，其中的选择性可以显着改变的局部条件，如局部pH值附近的表面或表面形态。为了理解这些现象，必须理解溶液中的质量传递与表面反应耦合的详细方式。 理解质量传输效应的一个重要工具是微流体电化学装置，其中流过反应电极的流体将中间体和产物扫到下游的检测器。将开发新的电化学检测方法。我们还将增加下游光谱方法，包括拉曼（与Brolo，UVic合作）和DEMS（与Seland和Sunde，NTNU，挪威合作）。 我们将使用快速电化学方法来理解动力学，包括基于动态电化学阻抗谱的方法，该方法可以捕获作为时间函数的阻抗谱。我们将扩展这种方法和支持理论的能力。 Pt和Pd电极上的薄氧化物膜通常抑制电催化活性。尽管研究了多年，氧化物的性质，它如何生长以及它如何影响电催化仍然知之甚少。与Drnec（欧洲同步辐射设施）和Magnussen（基尔）合作，我们将应用同步辐射表面X射线衍射来研究氧化物的结构及其形成的动力学。 多种电化学和光谱方法的结合使用将给出一个全面的图片有关选定的有机氧化和CO2还原反应的电催化反应机理。