CO2electrolyzer Development: Preliminary Results from a Bipolar-Membrane-Based Flow Cell for Electrocatalytic Reduction of Carbon Dioxide

Abstract

The electrocatalytic reduction of carbon dioxide (CO2) to useful chemicals and fuels is an area of great importance and interest. However, the 10’s of mA/cm2 current densities in aqueous-based reactors must be scaled up one or two orders of magnitude for it to be integrated in to industrial processes. Several groups have shown this is possible by introducing CO2 to the cathode in the gas-phase via a gas diffusion electrode. Through a robust fuel cell research program, NREL has developed considerable expertise in manipulating gas-phase reactions from the material to device level. That expertise has recently been leveraged to develop CO2 electrolyzers that use a gas-phase cathode for CO2 reduction, water oxidation in alkaline aqueous electrolyte as the proton and electron source, separated by a bipolar membrane with an engineered 3-D interfacial layer. In this talk, we will describe the details of our device design and show initial results from runs on our first reactor iteration. We will also describe our progress in designing and fabricating new automated test stands, with real-time online reduction product analysis, capable of performing in-situ electrochemical diagnostics on dynamic processes in these complex systems. The ultimate goal of this project is to establish a platform to evaluate and benchmark promising CO2 electrocatalysts under conditions relevant to their incorporation in to a tangible solution to the problem for which they are intended to address.