Gas diffusion electrodes
A Gas Diffusion Electrode (GDE) is a combination of porous structures exhibiting a hydrophilic and a hydrophobic side. It is generally composed of a catalyst layer (CL), a gas diffusion layer (GDL) and a current collector (CC) as shown in Figure 1. Such a GDE allows the direct supply of gases via the hydrophobic side to the liquid medium where electrochemical processes take place. Because of their low mass transfer resistance, the GDE is promising for electrochemical processes with gaseous reactants e.g. oxygen reduction to hydrogen peroxide and electrochemical CO2 reduction for the electrosynthesis of chemicals and synthetic fuels. Because of their porosity GDEs have a reactive surface area much larger than their geometrical area, which is favorable for the process productivities.
VITO CORE®, VITO CASE® and other VITO GDEs
There are many parameters influencing the performance of a GDE, like the composition, morphology, hydrophobicity of its individual layers. The effect of these parameters can however not be generalized for all processes. Research activities at VITO regarding GDEs involve tailoring and understanding the influence of the different properties on their performance. Engineering aspects in terms of upscaling and proper water and gas management are investigated and optimized.[1,2] VITO is able to tailor the pore size, water permeability and design structures fit for various sizes and purposes as shown in Figure 2. The VITO GDEs have been used by more than 30 industrial and academic partners all over the world. These electrodes are based on proprietary IP and are currently produced at pre-industrial scale and volumes.
Electrodes in the PERFORM project
In the PERFORM project, the activities are focused on the direct electrochemical conversion of sugar-based biomass. Upscaling and system level optimization are still a bottleneck for industrial implementation of the electrochemical technology. By using commercial catalytic nanomaterials, the catalyst developed by VITO itself as well those from partners such as INSTM, we will extend the usage of such electrocatalyst and eventually the VITO electrodes in conversion of sugar (glucose) to glucaric acid and further to adipic acid. We are studying and improving the electrocatalyst integration on the support and its morphology which realize an increase in current densities by an order of magnitude while the faradaic efficiency and selectivity to the resulting product (>80%). Although further improvements on a TRL 5 scale are underway, we have been able to demonstrate the technology on our bench scale reactor using a 10 cm2 VITO electrode.
 Sánchez et al., Current Opinion in Green and Sustainable Chemistry 2019, 16:47–56
More information- https://vito.be/en/product/gas-diffusion-electrodes