(Keynote) Electrolyzer Development and Process Optimization: Paving the Road for Industrial Carbon-Dioxide Electroreduction

Abstract

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. I will show how to optimize the cell components, to simultaneously provide industrially relevant performance, such as high partial current density (up to 800 mA cm-2), low cell voltage (−2.8-3.2 V), high conversion efficiency (up to 45 %), and high selectivity for CO production (over 95%).I will also demonstrate our CO2 electrolyzer cell, where multiple layers are connected into an electrolyzer stack, thus scaling up the electrolysis process. The operation of the cell was validated using both silver nanoparticle and copper nanocube catalysts. Evenly distributing the CO2 gas among the layers (parallel connection), the operation of the cell stack was identical to the sum of multiple single-layer cells. When passing the CO2 gas through the layers one after the other (serial gas connection), the CO2 conversion efficiency was increased remarkably.Finally, I will show how the cell 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 presented. Finally, the nature of ion-transport through the anion exchange membrane as a function of the operational conditions will be discussed.