Electrocatalysis in non-thermal plasma for energy storage

能源转型需要发展技术，允许有效的能源储存和转换，或允许脱碳重要的工业过程。电化学过程本质上是节能的，但是一些电子转移过程（例如，二氧化碳的减少）的缓慢仍然使它们的效率不够高，不足以克服它们的成本。等离子体催化也被提出用于其中一些过程，因为即使在环境温度下，通过这些分子与高能量电子的碰撞，它也能激活高度稳定的分子，如CO2和N2。该方法使催化过程的电气化成为可能，避免了有毒或危险化学品的使用。最近的研究表明，等离子体可以作为电化学电池中的电解质，这为等离子体和电催化结合以获得两全其美的可能性打开了令人兴奋的大门。然而，这些研究要么使用火焰（热等离子体）作为电解质，要么缺乏对电极-等离子体界面对外加电位响应的详细研究。我们建议对等离子体中相关的电化学过程进行基础研究，旨在确定在何种条件下CO2的电化学还原可以有效地和有良好的选择性地实现。我们将重点放在铜电极上，因为铜是唯一一种在水介质中电化学还原二氧化碳产生碳氢化合物的材料（与其他材料一起，还原不会超过一氧化碳或甲酸）。该项目还将包括设计电池和方法，以记录电化学实验期间的红外和光学发射光谱，目的是识别反应的中间体和产物，从而阐明反应机制、产物分布和产率。在第二阶段，对发生在电极-等离子体界面的反应的深入了解将用于建立等离子体电解槽的实验室原型，将二氧化碳转化为碳氢化合物。虽然我们将重点关注二氧化碳的减少和氢的氧化（这两个反应涉及冷等离子体二氧化碳电解槽，目的是产生碳氢化合物），但它们将是世界上第一个，一旦发展起来，它们将为我们和其他实验室的其他类似反应研究建立标准。此外，由于氢的氧化也必须是其他相关过程中的半反应之一（例如，氮作为氨的固定），我们的工作也将为将技术多样化到二氧化碳还原以外的过程提供重大进展。

The Energy Transition requires the development of technologies that allow for efficient energy storage and conversion or allow to decarbonise important industrial processes. Electrochemical processes are inherently energy efficient, but the sluggishness of some electron transfer processes (e.g., the reduction of CO2) often still makes their efficiency not high enough to overcome their cost. Plasma catalysis has also been proposed for some of these processes as it enables the activation of highly stable molecules like CO2 and N2 even at ambient temperatures through the collision of these molecules with highly energetic electrons. The method makes possible the electrification of catalytic processes, avoiding the use of toxic or hazardous chemicals. It has been recently shown that plasmas can act as the electrolyte in an electrochemical cell, which opens the doors to the exciting possibility of joining plasma and electrocatalysis to obtain the best of both worlds. However, these studies either used a flame (a hot plasma) as the electrolyte or lacked a detailed study of the response of the electrode-plasma interface to an applied potential.We propose a fundamental study of relevant electrochemical processes in plasmas aimed at identifying conditions under which the electrochemical reduction of CO2 to useful products can be achieved efficiently and with good selectivity. We will focus on Cu electrodes because copper is the only material on which the electrochemical reduction of CO2 in aqueous media results in hydrocarbons (with other materials reduction does not go beyond carbon monoxide or formic acid). The project will also involve the design of cells and methodologies to record infrared and optical emission spectra during the electrochemical experiments, with the aim of identifying intermediates and products of the reaction, thereby elucidating reaction mechanisms and product distributions and yields. In a second stage, the deep understanding of the reactions occurring at the electrode-plasma interface will be used to build a lab prototype of a plasma electrolyser converting CO2 to hydrocarbons.Although we will focus on the reduction of CO2 and the oxidation of hydrogen (the two reactions involved in a cold-plasma CO2 electrolyser aiming at producing hydrocarbons), they will set a world first, and once developed they will establish the standard for similar studies of other reactions in our and other laboratories. Furthermore, because the oxidation of hydrogen must also be one of the half reactions in other relevant processes (e.g., the fixation of nitrogen as ammonia) our work will also provide significant advance towards diversifying the technology to processes other than CO2 reduction.