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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.


a) Cyclic voltammograms for copper-phthalocyanine-modified H-terminated BDD in N2-saturated 0.1 m PBS pH 7 containing 0.0–2.0 mm H2O2 (dashed line: 0.0 mm). Scan rate: 100 mV s−1. b) Plot of peak current against concentration of H2O2.
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fig08: a) Cyclic voltammograms for copper-phthalocyanine-modified H-terminated BDD in N2-saturated 0.1 m PBS pH 7 containing 0.0–2.0 mm H2O2 (dashed line: 0.0 mm). Scan rate: 100 mV s−1. b) Plot of peak current against concentration of H2O2.

Mentions: The unmodified H-terminated diamond surface was examined by cyclic voltammetry in an N2-saturated solution, and the measurement was featureless for the reduction of hydrogen peroxide. Standard addition of hydrogen peroxide was then conducted on the copper-phthalocyanine-modified H-terminated diamond in an N2-saturated PBS to study the reaction without contribution from dioxygen. Figure 8 a shows the cyclic voltammograms of hydrogen peroxide for concentrations of 0.0 to 2.0 mm, with a peak potential of −0.57 V (vs. Ag/AgCl) at 0.1 mm. The magnitude of the peak current increases linearly with the hydrogen peroxide concentration, as shown in Figure 8 b, and the gradient of the calibration plot is −121.4 μA mM−1.


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

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

a) Cyclic voltammograms for copper-phthalocyanine-modified H-terminated BDD in N2-saturated 0.1 m PBS pH 7 containing 0.0–2.0 mm H2O2 (dashed line: 0.0 mm). Scan rate: 100 mV s−1. b) Plot of peak current against concentration of H2O2.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig08: a) Cyclic voltammograms for copper-phthalocyanine-modified H-terminated BDD in N2-saturated 0.1 m PBS pH 7 containing 0.0–2.0 mm H2O2 (dashed line: 0.0 mm). Scan rate: 100 mV s−1. b) Plot of peak current against concentration of H2O2.
Mentions: The unmodified H-terminated diamond surface was examined by cyclic voltammetry in an N2-saturated solution, and the measurement was featureless for the reduction of hydrogen peroxide. Standard addition of hydrogen peroxide was then conducted on the copper-phthalocyanine-modified H-terminated diamond in an N2-saturated PBS to study the reaction without contribution from dioxygen. Figure 8 a shows the cyclic voltammograms of hydrogen peroxide for concentrations of 0.0 to 2.0 mm, with a peak potential of −0.57 V (vs. Ag/AgCl) at 0.1 mm. The magnitude of the peak current increases linearly with the hydrogen peroxide concentration, as shown in Figure 8 b, and the gradient of the calibration plot is −121.4 μA mM−1.

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.