Development of highly stable gas diffusion layers for electrochemical CO2 reduction
Electrochemical reduction can convert CO2 to a vast array of interesting chemicals (including carbon monoxide and formic acid) using electricity as the direct driving force. To obtain industrially relevant activities, efficient supply of reagents to the catalyst is the critical factor that determines the overall CO2 electrolyzer performance. The gas diffusion layer (GDL) is the environment where CO2, electrons and water meet. Thus far, the design of GDLs for CO2 electrolysis has been mainly based on repurposed fuel cell materials. These are not tailored to CO2 electrolysis applications, and as a result often exhibit limited durability, with performance decay after a few hours of operation. We propose to build a GDL by using covalent triazine frameworks (CTFs) as the base material, which will be more active, but foremost more durable than the current GDL technology. The proposed GDL consists of three distinct layers: the structural base will be a carbon cloth, onto which we will grow a hydrophobic CTF. On top of this hydrophobic layer, we will add a second layer of CTF, which serves as the support for the catalyst nanoparticles. This CTF will be made of a mixture of different monomers, which each contain a desired property that further enhances the cell performance. The novel GDL will be loaded with two different state-of-the art catalysts based on earth-abundant metals, and tested for long-term stability and activity for the production of either CO or formic acid.