Surface and Microfluidic Electrochemistry

提出的电化学研究旨在了解小有机分子在贵金属电极上电催化反应的细节。将小的（液体）有机分子氧化成二氧化碳是直接液体燃料电池（dlfc）的基础。将二氧化碳还原为小有机分子可以取代化石燃料生成这些分子的途径，dlfc与二氧化碳减排的结合是实现可持续碳中和化学经济的一条途径。****这些反应是复杂的多步反应，通常涉及许多表面物质和溶液中间体，对所需产物的完美选择性不易实现。为了优化选择性，需要详细研究这些物质的性质和转化动力学。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来寻找新的催化剂。****电化学、微流体和光谱方法的结合将用于阐明这些反应中的各个步骤。特别是，这些方法的新组合将实时地观察这些转换。最近，已经发现了一些例子，其中选择性可以被局部条件显著改变，例如表面附近的局部pH值或表面形态。要理解这些现象，必须了解溶液中质量输运与表面反应耦合的详细方式。****了解质量传递效应的一个重要工具是在微流控电化学装置中，其中流过反应电极的流体将中间体和产物扫向下游的检测器。新的电化学检测方法将得到发展。我们还将增加下游光谱方法，包括Raman（与UVic的Brolo合作）和dem（与挪威NTNU的Seland and Sunde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，它可以捕获阻抗谱作为时间的函数。我们将扩展这种方法和支持理论的能力。**** Pt和Pd电极上的氧化薄膜通常会抑制电催化活性。尽管经过多年的研究，氧化物的性质、它的生长方式以及它对电催化的影响仍然知之甚少。在与Drnec（欧洲同步辐射设施）和Magnussen（基尔）的合作下，我们将应用同步加速器表面x射线衍射来研究氧化物的结构及其形成动力学。****多种电化学和光谱学方法的结合使用将对选定的有机氧化和CO2还原反应的电催化反应机理有一个全面的了解。******

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.******