INVESTIGATION OF O-2 REDUCTION IN ALKALINE MEDIA ON MACROCYCLIC CHELATES IMPREGNATED ON DIFFERENT SUPPORTS - INFLUENCE OF THE HEAT-TREATMENT ON STABILITY AND ACTIVITY

Several macrocyclic chelates impregnated on different carbon supports were investigated using a three-phase electrode. Pyrolysed CoTMPP on treated Vulcan yields comparable results to dispersed Pt. XPS investigations reveal, for the most stable compounds, either a special bond with carbon (CoTMPP) or in some cases nitride formation (MoNPc). With the most active compounds, the MeN4 unit is preserved after heat treatment. The affinity of carbon or nitrogen with the metal compared to the O2 affinity is essential. © 1990 Chapman and Hall Ltd.