ELECTROCATALYSTS FOR THE REDUCTION OF O-2 AND H2O2 BASED ON COMPLEXESOF CU(II) WITH THE STRONGLY ADSORBING 2,9-DIMETHYL-1,10-PHENANTHROLINE LIGAND

The complex of Cu2+ with one molecule of 2,9-dimethyl-1,10-phenanthrol ine is strongly and irreversibly adsorbed on graphite electrodes where it functions as an electrocatalyst for the reduction of O2 and H2O2. The corresponding complex involving two molecules of the ligand is als o strongly adsorbed but is not catalytically active. The methyl groups in the 2 and 9 positions of the phenanthroline ring produce a signifi cant positive shift in the potential where the adsorbed catalyst funct ions compared with the unsubstituted complex. The catalytic mechanism is argued to involve intramolecular electron transfer between the redu ced copper center and substrate coordinated to it.