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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.


Tafel plots of cathodic current for O2-saturated 0.1 m PBS pH 7 at scan rates from 50–200 mV s−1.
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fig07: Tafel plots of cathodic current for O2-saturated 0.1 m PBS pH 7 at scan rates from 50–200 mV s−1.

Mentions: Tafel analyses on the above data are shown in Figure 7, and an average value for of 0.46 was derived from the gradients of the plots. The concentration of oxygen in a saturated solution is 1.3 mm,21 and the diffusion coefficient for oxygen is 2.1×10−5 cm2 s−1.22 Using these values and the gradient of the linear plot in Figure 6 b, the number of electrons transferred is calculated using Equation 4 to be 2, indicating the reduction of oxygen to hydrogen peroxide.


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

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

Tafel plots of cathodic current for O2-saturated 0.1 m PBS pH 7 at scan rates from 50–200 mV s−1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig07: Tafel plots of cathodic current for O2-saturated 0.1 m PBS pH 7 at scan rates from 50–200 mV s−1.
Mentions: Tafel analyses on the above data are shown in Figure 7, and an average value for of 0.46 was derived from the gradients of the plots. The concentration of oxygen in a saturated solution is 1.3 mm,21 and the diffusion coefficient for oxygen is 2.1×10−5 cm2 s−1.22 Using these values and the gradient of the linear plot in Figure 6 b, the number of electrons transferred is calculated using Equation 4 to be 2, indicating the reduction of oxygen to hydrogen peroxide.

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.