Surface Modification of Boron-Doped Diamond with Microcrystalline Copper Phthalocyanine: Oxygen Reduction Catalysis.
Surface modification of boron-doped diamond (BDD) with copper phthalocyanine was achieved using a simple and convenient dropcast deposition, giving rise to a microcrystalline structure. Both unmodified and modified BDD electrodes of different surface terminations (namely hydrogen and oxygen) were compared via the electrochemical reduction of oxygen in aqueous solution. A significant lowering of the cathodic overpotential by about 500 mV was observed after modification of hydrogen-terminated (hydrophobic) diamond, while no voltammetric peak was seen on modified oxidised (hydrophilic) diamond, signifying greater interaction between copper phthalocyanine and the hydrogen-terminated BDD. Oxygen reduction was found to undergo a two-electron process on the modified hydrogen-terminated diamond, which was shown to be also active for the reduction of hydrogen peroxide. The lack of a further conversion of the peroxide was attributed to its rapid diffusion away from the triple phase boundary at which the reaction is expected to exclusively occur.
Chemistry Research Laboratory, University of Oxford Mansfield Road, Oxford, OX1 3TA, United Kingdom.
Patrick
P
Gan
Chemistry Research Laboratory, University of Oxford Mansfield Road, Oxford, OX1 3TA, United Kingdom.
John S
JS
Foord
Physical and Theoretical Chemistry Laboratory, University of Oxford South Parks Road, Oxford, OX1 3QZ, United Kingdom.
Richard G
RG
Compton
boron-doped diamond; catalysis; copper phthalocyanine; oxygen reduction; surface modification