Limits...
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.


Cyclic voltammogram for copper-phthalocyanine-modified O-terminated BDD in O2-saturated 0.1 m PBS pH 7. Scan rate: 100 mV s−1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4608528&req=5

fig05: Cyclic voltammogram for copper-phthalocyanine-modified O-terminated BDD in O2-saturated 0.1 m PBS pH 7. Scan rate: 100 mV s−1.

Mentions: The cyclic voltammograms on the modified H-terminated surface in both O2- and N2-saturated PBS are shown in Figure 4. While the curve obtained in the N2-saturated solution is relatively featureless, a large and irreversible cathodic peak was observed at −0.58 V (vs. Ag/AgCl) in the O2-saturated solution attributed to the reduction of oxygen. This represents a significant decrease in overpotential of over 500 mV compared to the unmodified H-terminated electrode and demonstrates the substantial electrocatalytic effect as a result of copper-phthalocyanine modification. The behaviour for the modified O-terminated diamond is very different, however, as shown in Figure 5. No apparent peak was observed for the voltammetric response in O2-saturated solution.


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

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

Cyclic voltammogram for copper-phthalocyanine-modified O-terminated BDD in O2-saturated 0.1 m PBS pH 7. Scan rate: 100 mV s−1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig05: Cyclic voltammogram for copper-phthalocyanine-modified O-terminated BDD in O2-saturated 0.1 m PBS pH 7. Scan rate: 100 mV s−1.
Mentions: The cyclic voltammograms on the modified H-terminated surface in both O2- and N2-saturated PBS are shown in Figure 4. While the curve obtained in the N2-saturated solution is relatively featureless, a large and irreversible cathodic peak was observed at −0.58 V (vs. Ag/AgCl) in the O2-saturated solution attributed to the reduction of oxygen. This represents a significant decrease in overpotential of over 500 mV compared to the unmodified H-terminated electrode and demonstrates the substantial electrocatalytic effect as a result of copper-phthalocyanine modification. The behaviour for the modified O-terminated diamond is very different, however, as shown in Figure 5. No apparent peak was observed for the voltammetric response in O2-saturated solution.

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.