HYDROGEN OXIDATION CHARACTERISTICS OF RANEY-NICKEL ELECTRODES WITH CARBON-BLACK IN AN ALKALINE FUEL-CELL

The characteristics of hydrogen oxidation of Raney nickel electrodes c ontaining carbon black in an alkaline fuel cell are investigated in 6 M KOH at 80 degrees C. The addition of conductive material to these el ectrodes is shown to increase both the limiting current density for hy drogen oxidation and the diffusivity of hydroxide ions. The catalytic activity of Raney nickel electrodes containing carbon black is about t wice that of an undoped electrode. A Raney nickel electrode with 8 wt. % Vulcan XC-72 exhibits the highest performance due to the high conduc tivity and high diffusivity of hydroxide ions at the electrode. The po re volume of the micropores increases with increase in the content of carbon black, but the pore volume of the macropores gradually decrease s. (C) 1998 Elsevier Science S.A. All rights reserved.