A study of cathode catalysis for the aluminium/hydrogen peroxide semi-fuel cell

The characterization and use of a Pd and Ir catalyst combination on a C substrate in an Al/H2O2 semi-fuel cell is described. The Pd–Ir combination outperforms Pd alone or Ir alone on the same substrate. Scanning electron microscopy (SEM) and energy dispersive spectrophotometry (EDS) were used to establish the location of Pd, Ir and O in clusters on the cathode substrate surface. X-ray photoelectron spectroscopy (XPS) binding energy measurements indicate that Pd is in the metallic state and the Ir is in the +3 state. A configuration consisting of an Ir(III) oxide (Ir2O3) core and a Pd shell is proposed. The electrochemical, corrosion, direct and decomposition reactions which take place during cell discharge were evaluated. Improved initial and long term performance, at low current densities, of the Al/H2O2 semi-fuel cell incorporating a Pd–Ir on C cathode relative to a similarly catalyzed Ni substrate and a baseline silver foil catalyst is demonstrated.