Oxygen Reduction on Transition‐Metal Porphyrins in Acid Electrolyte II. Stability

The stability of untreated and heat‐treated Co and FeT(p‐OCH 3 )PP/Norit BRX (T(p‐OCH 3 )PP = meso‐tetra(p‐methoxy)phenylporphyrin) has been studied under a variety of conditions: in pure electrolyte (6N H 2 SO 4 ), in the presence of H 2 O 2 , and under a current load (O 2 reduction); all at various temperatures. It appears that the heat‐treated Co catalyst has adequate stability for most low‐temperature applications (6NH 2 SO 4 , T ≤ 60° C , i ≤ 30 mA/cm 2 ).