Miikroelectrochemical investigation of the oxygen and CO2 reduction at gas diffusion electrodes

气体扩散电极处氧气和二氧化碳还原的微电化学研究

• 批准号: 316983898
• 负责人: Professor Dr. Wolfgang Schuhmann
• 金额: --
• 依托单位: Arbeitsgruppe Elektroanalytik und Sensorik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/316983898?language=en
• 关键词: Miikroelectrochemical; investigation; oxygen; CO2; reduction

The application of the silver/PTFE GDEs already utilized during the first funding period will be extended beyond its present use for the catalysis of the oxygen reduction reaction (ORR) in the context of the industrial chlor-alkali electrolysis process. We were already able to show that elec-trochemical reactions, such as the hydroxide producing ORR, pose a barely acknowledged yet substantial influence on the reaction environment. It is expected that the local activity of hydroxide rises whereas the water activity is decreasing, leading to a diminished reaction rate due to a rise in the local pH and a change in the reactant solubility. We want to use silver/PTFE based GDEs fabricated in the coordination project (KO) and in TP1 (Turek) for the electrochemical reduction of CO2 with concurrent modulation of the local pH via the ORR. Silver is known to yield mainly H2 and CO2 because of an overlap of the required potentials. We hypothesize that the selectivity of the CO2RR can be shifted towards the production of CO by modulating the local reaction environ-ment. Increasing the local pH may inhibit the parasitic hydrogen evolution (HER) which in turn would increase the faradaic efficiency for CO. In addition, we plan to investigate the influence of the CO2RR on the electrochemical environment utilizing a SECM based methodology that was developed during the first funding period. By modification of SECM based methods we want to elucidate local dynamic changes inside the GDE. Furthermore, the gained insights shall be valida-ted using vibrational spectroscopies with a conceptually new operando Raman cell. We expect to be able to experimentally validate simulations from TP1 (Turek) and TP2 (Krewer) and to define sophisticated input parameters for novel GDE models. Moreover, we plan to perform model electrowetting experiments in capillaries as input for TP4 (Manke) and TP5 (Nieken).

在第一个供资期内已经使用的银/PTFE GDE的应用范围将扩大到其目前在工业氯碱电解过程中催化氧还原反应的用途之外。我们已经能够证明，电化学反应，如氢氧化物产生ORR，对反应环境产生了几乎没有被承认但实质性的影响。预计氢氧化物的局部活性升高，而水活性降低，导致由于局部pH升高和反应物溶解度变化而导致反应速率降低。我们希望使用在协调项目（KO）和TP 1（Turek）中制造的银/PTFE基GDE，用于CO2的电化学还原，同时通过ORR调节局部pH。已知银主要产生H2和CO2，因为所需电势重叠。我们推测，CO2 RR的选择性可以转向生产CO通过调节本地的反应流程。增加当地的pH值可能会抑制寄生析氢（HER），这反过来又会增加法拉第效率为CO。此外，我们计划调查的影响CO2 RR的电化学环境，利用SECM为基础的方法，在第一个资助期内开发。通过修改SECM为基础的方法，我们要阐明GDE内的局部动态变化。此外，所获得的见解应使用振动光谱与一个概念上新的operando拉曼细胞进行验证。我们希望能够通过实验验证TP 1（Turek）和TP 2（Krewer）的模拟，并为新的GDE模型定义复杂的输入参数。此外，我们计划在毛细管中进行模型电润湿实验，作为TP 4（Manke）和TP 5（Nieken）的输入。