On the effect of various active carbon catalysts on the behaviour of carbon gas-diffusion air electrodes: 1. Alkaline solutions

Abstract

The electrochemical behaviour of carbon gas-diffusion air electrodes in alkaline solutions was investigated. Electrodes with defined structural and hydrophobic properties were chosen as a suitable system for comparing the electrochemical activity of different active carbon catalysts. The current-voltage characteristics of electrodes with 11 different active carbon catalysts were investigated when operating both with air and pure oxygen. The mass transport hindrances of the electrodes were studied in terms of Δ E( i) curves. Potential recovery transients of the electrodes were correlated with the electrochemical activity of the different active carbon catalysts. On the basis of the experimental results the active carbon sample with the most suitable structural properties was chosen as a proper carrier to be promoted with small amounts of metal catalyst. The electrode with active carbon promoted with small amounts of metal catalyst. The electrode with active carbon promoted with 1.5/cm 2 silver loaded with 100 mA/cm 2 has a potential of −67 mV ( vs. Hg/HgO) when operating with oxygen and −106 mV when operating with air at room temperature.