Pulse method for long-term stable and selective CO2 electrolysis to ethene on copper-based gas diffusion electrodes

电化学还原人为产生的二氧化碳（CO2）为有价值的物质代表了一种有前途的技术，以限制威胁全球变暖。在这种所谓的CO2 RR中，使用了来自可再生能源的剩余电力，因此也为稳定电网做出了积极贡献。特别地，铜被用作反应的电催化剂，因为它起着特殊的作用并且能够形成C-C键。乙烯的反应将是特别经济的，因为它具有反应性双键并且可以以多种方式用作工业基础化学品。然而，缺点是铜的选择性低，这导致形成大量必须分离的产物。另一方面，存在催化剂和方法的低长期稳定性，这导致烃的产率显著降低，有利于寄生析氢。脉冲电位法，已经验证了在自己的初步工作，导致显着改善的稳定性和选择性的乙烯生成。作为工作假设，假设脉冲方法可以降低反应器中的浓度梯度，减少催化剂的中毒和/或周期性地形成新的催化剂表面。然而，这些工作假设中哪一个是正确的，只能通过将CO2 RR与操作分析相结合来确定。我们的目标是通过结合两个PI在电化学工程，新材料以及创新制造和操作表征方法方面的互补专业知识来解决这个双边项目中的挑战，以评估在接近现实的操作条件下流动电池中气体扩散电极（GDE）的脉冲方法的机制。面向应用的研究结果将使我们能够在未来的应用中，对GDE的优化设计和电解CO2 RR电池的操作模式提出基于知识的建议。

The electrochemical reduction of anthropogenic carbon dioxide (CO2) to valuable substances represents a promising technology for limiting the threatening global warming. In this so-called CO2RR, surplus electricity from renewable energy sources is used and thus it also positively contributes to stabilizing the electrical power grid. Copper, in particular, is used as an electrocatalyst for the reaction, as it plays a special role and is capable of forming C-C bonds. A reaction to ethylene would be particularly economical, since it has a reactive double bond and can be used in a variety of ways as an industrial base chemical. A disadvantage, however, is the low selectivity of copper, which leads to the formation of a large number of products that have to be separated. On the other hand, there is the low long-term stability of the catalyst and the process, which results in a significant decrease in the yield of hydrocarbons in favor of parasitic hydrogen evolution. The pulsed potential method, as already verified in own preliminary work, leads to a significant improvement in the stability and selectivity of the ethylene generation. As a working hypothesis, it is assumed that the pulsed method can reduce either the concentration gradients in the reactor, reduce the poisoning of the catalyst and/or periodically form new catalyst surfaces. However, which of these working hypotheses is correct can only be determined by coupling CO2RR with operando analytics. We aim to address this challenge in this bilateral project by combining the complementary expertise of both PIs in electrochemical engineering, new materials, as well as in innovative fabrication and operando characterization methods to evaluate the mechanism of the pulse method on gas diffusion electrodes (GDEs) in flow cells under operating conditions that are close to reality. The application-oriented findings will allow us to make knowledge-based suggestions regarding the optimal design of GDEs and operation modes of electrolytic CO2RR cells in future applications.