Development of gas diffusion electrodes for cogeneration of chemicals and electricity

This study reports the development and evaluation of gas diffusion electrodes (GDEs) for application in a fuel cell reactor aimed at the production of hydroxylamine. Electrode materials manufactured by two different methods are reported. The composition of the active layer of these electrodes has been tailored for application as gas diffusion cathodes for a NO-H2 fuel cell. The results on physico-chemical characterization of the catalyst layers (density, water porosity, total porosity and BET surface area) are discussed in relation with the differences in their composition (carbonaceous powder and binder used, ratios carbon to binder). The gas porous electrodes were first tested in an electrochemical half cell configuration (3-electrode configuration) for their ability to reduce diluted nitric oxide (6% in nitrogen). Later, the performance in a NO-H2 fuel cell was evaluated for the promising electrodes in a single cell set-up (2-electrode configuration). It was observed that non-platinized electrodes offer an acceptable performance for NO reduction. In the single cell set-up, current densities of −12 mA cm−2 for a non-platinized electrode and −10 mA cm−2 for a non-catalyzed activated charcoal electrode were obtained at 50 mV cell voltage, vs. 17 mA cm−2 for a platinized charcoal electrode.