Determination of the thicknesses of the active layer and cathode limiting currents in AFC

• A series of double-layered gas diffusion electrodes with two different electrocatalysts, i.e., Ag and pyrolyzed macrocycle mixture (PMM) were prepared in order to find out the maximum limiting current densities (i(L)) by varying the oxygen partial pressures in 6 M KOH and at 65 degreesC. As optimization of the active (catalyst) layer is important for better utilization of the catalytic reactions for oxygen reduction and thereby attainment of high current density, electrochemical measurements in half-cells were carried out to substantiate the current-thickness relationships. The thicknesses for both the active layers and diffusion layers were determined by using SEM. i(L) for an oxygen concentration simulating that of air was found to be 2.2 A cm(-2) for the PMM with 0.51 mm and 1.6 A cm-2 for the Ag-based catalyst with 0.56 mm thicknesses of the active layer. An overlay of a mathematical model, describing the parameters for determination of i(L), has also been inserted alongside the experimental values.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Nyckelord

oxygen reduction

Ag

pyrolyzed macrocycle

limiting current

thickness

active layer

alkaline fuel-cell

mathematical-model

oxygen

electrodes

reduction

electrocatalysts

area

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)