Tuesday, March 30, 2021
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Electrolyzer Development and Process Optimization: Paving the Road for Industrial Carbon-dioxide Electroreduction
Speaker: Csaba Janáky, Associate Professor, Department of Physical Chemistry and Materials Science, University of Szeged and ThalesNanoEnergy Zrt.
Electrochemical reduction of CO2 is a promising method for converting a greenhouse gas into value-added products, utilizing renewable energy. Novel catalysts, electrode assemblies, and cell configurations are all necessary to achieve economically appealing performance. In this talk, I am going to present a zero gap electrolyzer cell, which converts gas phase CO2 to products without the need for any liquid catholyte. This is the first report of a CO2 electrolyzer cell, where multiple cells are connected into a stack, thus scaling up the electrolysis process. The operation of the cell was validated using both silver nanoparticle and copper nanocube catalysts, and the first was employed for the optimization of the electrolysis conditions. Upon this, CO formation with partial current densities above 250 mA cm−2 were achieved routinely, which was further increased to 300 mA cm−2 (with ~95 % Faradaic efficiency) by pressurizing the CO2 inlet. Evenly distributing the CO2 gas among the cells (parallel connection), the operation of the multi-cell stack was identical to the sum of multiple single cells. When passing the CO2 gas through the cells one after the other (serial gas connection), the CO2 conversion efficiency was increased remarkably.
In the second part of the talk I will show how poly(aryl piperidinium)-based anion exchange membrane (PiperION) with high carbonate conductance was employed for CO2 electrolysis to CO in conjunction with a tailored electrolyzer cell structure. This combination results in unprecedentedly high partial current densities in zero-gap cells (jCO > 1.0 A cm−2), while maintaining high conversion (20-45%), selectivity (up to 90%) and low cell voltage (2.6-3.4 V).
Finally, I will present a zero-gap cell, which can operate with pure water feed on the anode side, therefore avoiding the use of alkaline anolyte. A carefully designed activation protocol will be presented, which allows the cell to operate at high current density, using pure water feed. The effect of temperature and flow rate on the operation will also be analyzed. Finally, the nature of ion-transport through the anion exchange membrane as a function of the operational conditions will be discussed.
About the Speaker
Dr. Csaba Janáky is an Associate Professor at Department of Physical Chemistry and Materials Science, University of Szeged, Hungary. He is the principal investigator of the MTA-SZTE “Momentum” Photoelectrochemistry Research Group, supported by the Hungarian Academy of Sciences and the European Research Council (ERC-Starting Grant). Csaba is also responsible for Green Economy and Climate Policy at the university and Chief Scientific Advisor of ThalesNanoEnergy Inc. He is an emerging expert of materials science oriented electrochemistry and photoelectrochemistry. He has developed new electrode materials for energy applications, such as CO2 reduction, water oxidation, and H2 evolution. He has published over 90 articles in peer-reviewed journals with an overall impact factor of 650. He is member of the Editorial Advisory Board of ACS Energy Letters and the Young Academy of Europe.