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Surface Modification of Boron-Doped Diamond with Microcrystalline Copper Phthalocyanine: Oxygen Reduction Catalysis.

Gan P, Foord JS, Compton RG - ChemistryOpen (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Chemistry Research Laboratory, University of Oxford Mansfield Road, Oxford, OX1 3TA, United Kingdom.

ABSTRACT
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.

No MeSH data available.


SEM micrographs of copper-phthalocyanine-modified a) H-terminated, b) O-terminated BDD. The scale bars represented by dotted lines are 15.0 μm (a) and 15.8 μm (b). Frame dimensions (h×w) are ∼69×58 μm (a) and ∼73×61 μm (b).
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fig03: SEM micrographs of copper-phthalocyanine-modified a) H-terminated, b) O-terminated BDD. The scale bars represented by dotted lines are 15.0 μm (a) and 15.8 μm (b). Frame dimensions (h×w) are ∼69×58 μm (a) and ∼73×61 μm (b).

Mentions: A simple dropcast technique was used to immobilise copper phthalocyanine onto the diamond electrode as described in the experimental section, and the surface morphology of the modified H- and O-terminated electrodes were characterised by scanning electron microscopy (SEM). As revealed by the SEM micrographs in Figure 3, the structure of the modified electrodes both consisted of microcrystalline deposits of varying sizes up to about 7 μm in length across the diamond surface.


Surface Modification of Boron-Doped Diamond with Microcrystalline Copper Phthalocyanine: Oxygen Reduction Catalysis.

Gan P, Foord JS, Compton RG - ChemistryOpen (2015)

SEM micrographs of copper-phthalocyanine-modified a) H-terminated, b) O-terminated BDD. The scale bars represented by dotted lines are 15.0 μm (a) and 15.8 μm (b). Frame dimensions (h×w) are ∼69×58 μm (a) and ∼73×61 μm (b).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608528&req=5

fig03: SEM micrographs of copper-phthalocyanine-modified a) H-terminated, b) O-terminated BDD. The scale bars represented by dotted lines are 15.0 μm (a) and 15.8 μm (b). Frame dimensions (h×w) are ∼69×58 μm (a) and ∼73×61 μm (b).
Mentions: A simple dropcast technique was used to immobilise copper phthalocyanine onto the diamond electrode as described in the experimental section, and the surface morphology of the modified H- and O-terminated electrodes were characterised by scanning electron microscopy (SEM). As revealed by the SEM micrographs in Figure 3, the structure of the modified electrodes both consisted of microcrystalline deposits of varying sizes up to about 7 μm in length across the diamond surface.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Chemistry Research Laboratory, University of Oxford Mansfield Road, Oxford, OX1 3TA, United Kingdom.

ABSTRACT
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.

No MeSH data available.