Bolade Agboola - Academia.edu (original) (raw)
Papers by Bolade Agboola
International journal of electrochemical science
ABSTRACT
Bulletin of the Chemical Society of Ethiopia, 2001
Talanta, 2007
This work reports on the use of Co(II), Fe(II), Mn(III) and Ni(II) tetrakis benzylmercapto and do... more This work reports on the use of Co(II), Fe(II), Mn(III) and Ni(II) tetrakis benzylmercapto and dodecylmercapto phthalocyanine complexes for gold electrode modification for electrooxidation of sulphite ions. The complexes were successfully used to modify gold electrodes by self-assembled monolayer (SAM) technique. The self-assembled films are stable and showed blocking characteristics towards the following Faradaic processes; gold surface oxidation, underpotential deposition (UPD) of copper and solution redox chemistry of [Fe(H(2)O)(6)(3+)]/[Fe(H(2)O)(6)(2+)]. All the modified electrodes showed improved catalytic activities than the unmodified gold electrode towards sulphite ion electrooxidation with all the modified electrodes exhibiting high resistance to electrode surface passivation. Better catalytic performance were obtained for the CoPcs, FePcs and MnPcs which have metal based redox processes within the range of the sulphite electrooxidation peak, while the NiPcs which did not show metal based redox reaction performed less. The catalytic current was found to be linear with sulphite ion concentration in the concentration range employed in this work (0.1-1mM) and sensitivities ranging from 1.68 to 2.96muA/mM were observed for all the modified electrodes. Mechanisms of the catalytic oxidation of sulphite ions are proposed.
Sensors and Actuators B: Chemical, 2010
... All images (256 samples/line × 256 lines) were taken in air at room temperature and at scan r... more ... All images (256 samples/line × 256 lines) were taken in air at room temperature and at scan rates 0.5–0.6 lines s −1 . The X-ray photoelectron spectra (XPS) were obtained using a Physical Electronics model 5400 spectrometer system with monochromatic Mg Kα radiation at ...
Physical Chemistry Chemical Physics, 2008
Electrochemical properties of redox-active self-assembled molecular films of novel metallo-octaca... more Electrochemical properties of redox-active self-assembled molecular films of novel metallo-octacarboxyphthalocyanine (MOCPc, M = Fe, Co and Mn) complexes integrated with cysteamine (Cys) monolayer on gold electrodes via amide bonds were investigated. X-Ray photoelectron spectroscopy confirmed the appearance of the various elements in their expected chemical environment upon immobilization of these species. The heterogeneous electron transfer properties of the Au-Cys-MOCPc molecular films using an outer-sphere ([Fe(CN)(6)](4-)/[Fe(CN)(6)](3-)) redox probe were studied using cyclic voltammetry and electrochemical impedance spectroscopy. The electron transfer rate constant (k(app)) depends markedly on the central metal of the metallophthalocyanine cores (k(app): Co > Mn > Fe). A strong pH dependence of the electron transport of the Au-Cys-MOCPc molecular films was found. The surface pK(a) values of the MOCPc complexes were essentially the same (ca. 7.5). The differences in the electron transports and ionization constants are discussed. The electrodes are sensitive to the electrooxidation of epinephrine in physiological pH conditions, peak potential (E(p)/V vs. Ag|AgCl, saturated KCl) decreasing as FeOCPc (0.20 V) < MnOCPc (0.26 V) < CoOCPc (0.34 V).
Journal of Solid State Electrochemistry, 2013
ABSTRACT Supercapacitive properties of synthesised metal oxides nanoparticles (MO where M = Ni, C... more ABSTRACT Supercapacitive properties of synthesised metal oxides nanoparticles (MO where M = Ni, Co, Fe) integrated with multi-wall carbon nanotubes (MWCNT) on basal plane pyrolytic graphite electrode (BPPGE) were investigated. Successful modification of the electrode with the MWCNT-MO nanocomposite was confirmed with spectroscopic and microscopic techniques. Supercapacitive properties of the modified electrodes in sulphuric acid (H2SO4) and sodium sulphate (Na2SO4) electrolytes were investigated using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic constant current charge–discharge (CD) techniques. The specific capacitance values followed similar trend with that of the cyclic voltammetry and the electrochemical impedance experiments and are slightly lower than values obtained using the galvanostatic charge–discharge cycling. MWCNT-NiO-based electrode gave best specific capacitance of 433.8 mF cm−2 (ca 2,119 F g−1) in H2SO4. The electrode exhibited high electrochemical reproducibility with no significant changes over 1,000 cyclic voltammetry cycles.
Journal of Solid State Electrochemistry, 2009
ABSTRACT
Journal of Power Sources, 2010
ABSTRACT Supercapacitive behaviour of a novel functional material, nickel (II) octa [(3,5-biscarb... more ABSTRACT Supercapacitive behaviour of a novel functional material, nickel (II) octa [(3,5-biscarboxylate)-phenoxy] phthalocyanine (NiOBCPPc) upon covalent integration with phenylamine functionalized single-walled carbon nanotubes (SWCNT-phenylamine) is reported for the first time. The supercapacitive behaviour of the hybrid (NiOBCPPc-SWCNT-phenylamine) was investigated using galvanostatic charge–discharge and electrochemical impedance spectroscopy. Using a more reliable galvanostatic charge–discharge method, the NiOBCPPc-SWCNT-phenylamine hybrid exhibited superior geometrical capacitance (∼186mFcm−2) compared to either NiOBCPPc (∼54mFcm−2) or SWCNT-phenylamine (∼74mFcm−2) at a current density of 138μAcm−2. The NiOBCPPc-SWCNT-phenylamine gave excellent stability of over 1000 charge–discharge continuous cycling.
Journal of Porphyrins and Phthalocyanines, 2008
ABSTRACT
Journal of Molecular Catalysis A: Chemical, 2005
ABSTRACT Cobalt tetrasulfophthalocyanine (CoTSPc) was used to catalyze the oxidation of 2-chlorop... more ABSTRACT Cobalt tetrasulfophthalocyanine (CoTSPc) was used to catalyze the oxidation of 2-chlorophenol (2-CP) and 2,4,5-trichlorophenol (TCP) using hydrogen peroxide (H2O2) as the oxidant. This CoTSPc catalyzed hydrogen peroxide oxidation of chlorophenols resulted in the formation of different types of oxidation products depending on the solvent conditions. In water/methanol conditions (where CoTSPc is mainly monomeric, and unionized forms of the phenols), phenol and hydroquinone were the main oxidation products, while in phosphate buffer solutions (pH 7 and 10 for TCP and 2-CP, respectively, where CoTSPc is mainly aggregated, and ionized forms of the phenols), benzoquinone was the main product. In contrast to CoTSPc, other MTSPc complexes studied (AlTSPc, CuTSPc and NiTSPc) exhibited no detectable catalytic effect on the oxidation of chlorophenols under the experimental conditions employed, thus proving the effect of the central metal ions on efficient catalysis of chlorophenol. Reaction pathways are proposed based on the relative time of oxidation products formation.
Journal of Molecular Catalysis A: Chemical, 2006
ABSTRACT Photolysis of aqueous solutions of chlorophenols (4-chlorophenol, 2,4-dichlorophenol, 2,... more ABSTRACT Photolysis of aqueous solutions of chlorophenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and pentachlorophenol) in the presence of immobilized non-transition metal phthalocyanine photosensitizers onto Amberlite® is presented. The photosensitizers studied are: Al (AlOCPc) and Zn (ZnOCPc) octacarboxyphthalocyanines; Al (AlPcS4) and Zn (ZnPcS4) tetrasulfophthalocyanines; sulfonated phthalocyanine complexes (containing mixtures of differently substituted derivatives) of Al (AlPcSmix), Zn (ZnPcSmix), Ge (GePcSmix), Si (SiPcSmix) and Sn (SnPcSmix). Photolysis of the chlorophenols resulted mainly in the formation of chlorobenzoquinone derivatives. The complexes showed order of activity towards the transformation of pentachlorophenol as follows: ZnOCPc>SiPcSmix>SnPcSmix>ZnPcSmix>GePcSmix>ZnPcS4>AlPcSmix>AlOCPc>AlPcS4. The generation of singlet oxygen (1O2) by these immobilized MPc photosensitizers was found to play a major role in their photoactivities towards the transformation of these chlorophenols. Langmuir–Hinshelwood (L–H) kinetic model studies showed that the ZnOCPc, GePcSmix and ZnPcSmix photocatalysis occurred on the catalysts surface.
Journal of Colloid and Interface Science, 2004
The redox activities of water-soluble iron͑II͒ tetrasulfophthalocyanine ͑FeTSPc͒ and single-walle... more The redox activities of water-soluble iron͑II͒ tetrasulfophthalocyanine ͑FeTSPc͒ and single-walled carbon nanotube-poly͑m-aminobenzene sulfonic acid͒ ͑SWCNT-PABS͒ adsorbed on a gold surface precoated with a self-assembled monolayer ͑SAM͒ of 2-dimethylaminoethanethiol ͑DMAET͒ have been described. Atomic force microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy were employed to probe the buildup and formation of their thin solid films on the gold surface. The solid films exhibited excellent electrochemical stability. The electrode based on the mixed hybrids ͑Au-DMAET-SWCNT-PABS/FeTSPc͒ exhibited the fastest electron transport ͑k o Ϸ 0.4 cm s −1 ͒ compared to other electrodes ͑ϳ0.2 cm s −1 ͒, suggesting the ability of the SWCNT-PABS to act as efficient conducting species that facilitate electron transport between the integrated FeTSPc and the underlying gold substrate. Given the paucity of literature in the SAMs of water-soluble phthalocyanine complexes, the proposed fabrication strategy could potentially be extended to other water-soluble metallophthalocyanines and related organometallic complexes.
... on Fluorine Doped SWCNT Template: A Novel and Smart Electrode Material for Li-Ion Battery. [E... more ... on Fluorine Doped SWCNT Template: A Novel and Smart Electrode Material for Li-Ion Battery. [ECS Meeting Abstracts 1003, 603 (2010)]. Bolade O. Agboola, HongzeLuo, Kenneth I. Ozoemena, Lukas Le Roux, Mkhulu Mathe.
... Coated Lithium Manganese Oxide Dispersed on Carbon Nanotubes. [ECS Meeting Abstracts 1003, 59... more ... Coated Lithium Manganese Oxide Dispersed on Carbon Nanotubes. [ECS Meeting Abstracts 1003, 598 (2010)]. Kenneth I. Ozoemena, Tendamudzimu Ramulifho, Bolade O. Agboola, Hongze Luo, Lukas Leroux, Mkhulu Mathe.
Al/F Surface Modified Single Crystalline Spinel LiMnO Nanowires/Nanorods as Cathode Material for ... more Al/F Surface Modified Single Crystalline Spinel LiMnO Nanowires/Nanorods as Cathode Material for Li-Ion Battery. [ECS Meeting Abstracts 1003, 616 (2010)]. Hongze Luo, Bolade O. Agboola, Kenneth I. Ozoemena, Lukas Le Roux, Mkhulu Mathe.
Energy & Environmental Science, 2010
The supercapacitive properties of nickel(II) tetraaminophthalocyanine (NiTAPc)/multi-walled carbo... more The supercapacitive properties of nickel(II) tetraaminophthalocyanine (NiTAPc)/multi-walled carbon nanotube (MWCNT) nanocomposite films have been interrogated for the first time and found to possess a maximum specific capacitance of 981 AE 57 F g À1 (200 AE 12 mF cm À2 ), a maximum power density of 700 AE 1 Wkg À1 , a maximum specific energy of 134 AE 8 Wh kg À1 and excellent stability of over 1500 charge-discharge continuous cycling. Impedimetric study proves that most of the stored energy of the MWCNT-NiTAPc nanocomposite can be accessible at high frequency (720 Hz). When compared to MWCNTs modified with unsubstituted nickel(II) phthalocyanine (MWCNT-NiPc) or nickel(II) tetratert-butylphthalocyanine (MWCNT-tBuNiPc), MWCNT-NiTAPc exhibited superior supercapacitive behaviour, possibly due to the influence of nitrogen-containing groups on the phthalocyanine rings.
Electrochimica Acta, 2006
Nickel tetrakis(benzylmercapto)phthalocyanine (NiTBMPc) and nickel tetrakis(dodecylmercapto)phtha... more Nickel tetrakis(benzylmercapto)phthalocyanine (NiTBMPc) and nickel tetrakis(dodecylmercapto)phthalocyanine (NiTDMPc) complexes were synthesized and their spectral and electrochemical properties reported. The CV showed four or five redox processes for NiTBMPc and NiTDMPc, respectively. For the first time, spectroelectrochemistry gave evidence for the formation of Ni II /Ni I process in a NiPc complex. The rest of the processes were ring based. The NiTBMPc complex was successfully deposited on both gold and glassy carbon electrodes by electropolymerisation while NiTDMPc complex was deposited on gold electrode only. The films were electrotransformed in aqueous 0.1 M NaOH solution to the O-Ni-O oxo bridged form. The modified electrodes were characterized using electrochemical impedance spectroscopy and the results showed typical behavior for modified electrodes. Electrodes with poly-Ni(OH)Pcs films exhibited higher charge transfer resistance values, R p than their corresponding poly-NiPcs films counterparts. All the modified electrodes showed improved catalytic activities than the unmodified electrodes towards nitrite ions electrooxidation. Better catalytic activities were observed for the modified electrodes when they were transformed to O-Ni-O oxo bridge form. All the modified electrodes exhibited high resistance to electrode surface passivation.
Electrochimica Acta, 2007
ABSTRACT This work reports on the use of nickel(II) tetrakis benzylmercapto (NiTBMPc) and dodecyl... more ABSTRACT This work reports on the use of nickel(II) tetrakis benzylmercapto (NiTBMPc) and dodecylmercapto (NiTDMPc) metallophthalocyanine complexes films on gold electrodes for the electrochemical oxidation of 4-chlorophenol (4-CP) and 2,4,5-trichlorophenol (TCP). Both NiTBMPc and NiTDMPc complexes were successfully deposited on gold electrodes by electropolymerisation. The films were electro-transformed in aqueous 0.1 M NaOH solution to the ‘O–Ni–O oxo’ bridged form. For both complexes, films with different thickness were prepared and characterised by electrochemical impedance and UV–vis (on indium tin oxide) spectroscopies and the results showed typical behaviour for modified electrodes with increasing charge transfer resistance values (Rp) with polymer thickness. The poly-Ni(OH)NiPcs showed better catalytic activity than their poly-NiPcs counterparts.
Electrochemistry Communications, 2009
Electrochemical behaviour of self-assembled monolayer of 2-dimethylaminoethanethiol (DMAET) on go... more Electrochemical behaviour of self-assembled monolayer of 2-dimethylaminoethanethiol (DMAET) on gold electrode, with and without integration with SWCNT-poly(m-aminobenzene sulphonic acid) (SWCNT-PABS) has been probed. It is proved that the so-called electric field induced protonation-deprotonation process, hitherto observed for the -COOH terminated SAMs, is also observed for the -N(H) + (CH 3 ) 2 terminated. The surface pK a of DMAET was estimated as 7.6, smaller than its solution pK a of 10.8. It is also shown that SWCNT-PABS is irreversibly attached to the DMAET SAM.
Electrochemistry Communications, 2007
Voltammetric characterisations of cobalt, iron, manganese, nickel and zinc phthalocyanine complex... more Voltammetric characterisations of cobalt, iron, manganese, nickel and zinc phthalocyanine complexes tetra substituted with benzyl-and dodecyl-mercapto ring substituents and immobilisation on gold electrodes via the self-assembling technique are presented. The self-assembled films are stable and showed blocking characteristics towards the following Faradaic processes; gold surface oxidation, under potential deposition of copper and solution redox chemistry of . The solution chemistry of [Fe(CN) 6 ] −3 /[Fe(CN) 6 ] −4 redox process was used to study the orientation of the CoPcs-SAMs and this revealed a possible deviation from flat orientation of the complexes on the gold electrodes when the SAM formation times were greater than 24 h. For SAM formation time at 24 and 48 h, CoTDMPc-SAM showed more inhibition of the [Fe(CN) 6 ] −3 /[Fe(CN) 6 ] −4 redox process than the CoTBMPc-SAM counterpart, indicating more blocking characteristics of the dodecylmercapto ring substituents compared to the benzylmercapto counterpart. To avoid SAM desorption, the potential application should be limited to −0.2 to +0.8 V vs. Ag AgCl (NaCl, sat'd) in acidic and neutral pH.
International journal of electrochemical science
ABSTRACT
Bulletin of the Chemical Society of Ethiopia, 2001
Talanta, 2007
This work reports on the use of Co(II), Fe(II), Mn(III) and Ni(II) tetrakis benzylmercapto and do... more This work reports on the use of Co(II), Fe(II), Mn(III) and Ni(II) tetrakis benzylmercapto and dodecylmercapto phthalocyanine complexes for gold electrode modification for electrooxidation of sulphite ions. The complexes were successfully used to modify gold electrodes by self-assembled monolayer (SAM) technique. The self-assembled films are stable and showed blocking characteristics towards the following Faradaic processes; gold surface oxidation, underpotential deposition (UPD) of copper and solution redox chemistry of [Fe(H(2)O)(6)(3+)]/[Fe(H(2)O)(6)(2+)]. All the modified electrodes showed improved catalytic activities than the unmodified gold electrode towards sulphite ion electrooxidation with all the modified electrodes exhibiting high resistance to electrode surface passivation. Better catalytic performance were obtained for the CoPcs, FePcs and MnPcs which have metal based redox processes within the range of the sulphite electrooxidation peak, while the NiPcs which did not show metal based redox reaction performed less. The catalytic current was found to be linear with sulphite ion concentration in the concentration range employed in this work (0.1-1mM) and sensitivities ranging from 1.68 to 2.96muA/mM were observed for all the modified electrodes. Mechanisms of the catalytic oxidation of sulphite ions are proposed.
Sensors and Actuators B: Chemical, 2010
... All images (256 samples/line × 256 lines) were taken in air at room temperature and at scan r... more ... All images (256 samples/line × 256 lines) were taken in air at room temperature and at scan rates 0.5–0.6 lines s −1 . The X-ray photoelectron spectra (XPS) were obtained using a Physical Electronics model 5400 spectrometer system with monochromatic Mg Kα radiation at ...
Physical Chemistry Chemical Physics, 2008
Electrochemical properties of redox-active self-assembled molecular films of novel metallo-octaca... more Electrochemical properties of redox-active self-assembled molecular films of novel metallo-octacarboxyphthalocyanine (MOCPc, M = Fe, Co and Mn) complexes integrated with cysteamine (Cys) monolayer on gold electrodes via amide bonds were investigated. X-Ray photoelectron spectroscopy confirmed the appearance of the various elements in their expected chemical environment upon immobilization of these species. The heterogeneous electron transfer properties of the Au-Cys-MOCPc molecular films using an outer-sphere ([Fe(CN)(6)](4-)/[Fe(CN)(6)](3-)) redox probe were studied using cyclic voltammetry and electrochemical impedance spectroscopy. The electron transfer rate constant (k(app)) depends markedly on the central metal of the metallophthalocyanine cores (k(app): Co > Mn > Fe). A strong pH dependence of the electron transport of the Au-Cys-MOCPc molecular films was found. The surface pK(a) values of the MOCPc complexes were essentially the same (ca. 7.5). The differences in the electron transports and ionization constants are discussed. The electrodes are sensitive to the electrooxidation of epinephrine in physiological pH conditions, peak potential (E(p)/V vs. Ag|AgCl, saturated KCl) decreasing as FeOCPc (0.20 V) < MnOCPc (0.26 V) < CoOCPc (0.34 V).
Journal of Solid State Electrochemistry, 2013
ABSTRACT Supercapacitive properties of synthesised metal oxides nanoparticles (MO where M = Ni, C... more ABSTRACT Supercapacitive properties of synthesised metal oxides nanoparticles (MO where M = Ni, Co, Fe) integrated with multi-wall carbon nanotubes (MWCNT) on basal plane pyrolytic graphite electrode (BPPGE) were investigated. Successful modification of the electrode with the MWCNT-MO nanocomposite was confirmed with spectroscopic and microscopic techniques. Supercapacitive properties of the modified electrodes in sulphuric acid (H2SO4) and sodium sulphate (Na2SO4) electrolytes were investigated using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic constant current charge–discharge (CD) techniques. The specific capacitance values followed similar trend with that of the cyclic voltammetry and the electrochemical impedance experiments and are slightly lower than values obtained using the galvanostatic charge–discharge cycling. MWCNT-NiO-based electrode gave best specific capacitance of 433.8 mF cm−2 (ca 2,119 F g−1) in H2SO4. The electrode exhibited high electrochemical reproducibility with no significant changes over 1,000 cyclic voltammetry cycles.
Journal of Solid State Electrochemistry, 2009
ABSTRACT
Journal of Power Sources, 2010
ABSTRACT Supercapacitive behaviour of a novel functional material, nickel (II) octa [(3,5-biscarb... more ABSTRACT Supercapacitive behaviour of a novel functional material, nickel (II) octa [(3,5-biscarboxylate)-phenoxy] phthalocyanine (NiOBCPPc) upon covalent integration with phenylamine functionalized single-walled carbon nanotubes (SWCNT-phenylamine) is reported for the first time. The supercapacitive behaviour of the hybrid (NiOBCPPc-SWCNT-phenylamine) was investigated using galvanostatic charge–discharge and electrochemical impedance spectroscopy. Using a more reliable galvanostatic charge–discharge method, the NiOBCPPc-SWCNT-phenylamine hybrid exhibited superior geometrical capacitance (∼186mFcm−2) compared to either NiOBCPPc (∼54mFcm−2) or SWCNT-phenylamine (∼74mFcm−2) at a current density of 138μAcm−2. The NiOBCPPc-SWCNT-phenylamine gave excellent stability of over 1000 charge–discharge continuous cycling.
Journal of Porphyrins and Phthalocyanines, 2008
ABSTRACT
Journal of Molecular Catalysis A: Chemical, 2005
ABSTRACT Cobalt tetrasulfophthalocyanine (CoTSPc) was used to catalyze the oxidation of 2-chlorop... more ABSTRACT Cobalt tetrasulfophthalocyanine (CoTSPc) was used to catalyze the oxidation of 2-chlorophenol (2-CP) and 2,4,5-trichlorophenol (TCP) using hydrogen peroxide (H2O2) as the oxidant. This CoTSPc catalyzed hydrogen peroxide oxidation of chlorophenols resulted in the formation of different types of oxidation products depending on the solvent conditions. In water/methanol conditions (where CoTSPc is mainly monomeric, and unionized forms of the phenols), phenol and hydroquinone were the main oxidation products, while in phosphate buffer solutions (pH 7 and 10 for TCP and 2-CP, respectively, where CoTSPc is mainly aggregated, and ionized forms of the phenols), benzoquinone was the main product. In contrast to CoTSPc, other MTSPc complexes studied (AlTSPc, CuTSPc and NiTSPc) exhibited no detectable catalytic effect on the oxidation of chlorophenols under the experimental conditions employed, thus proving the effect of the central metal ions on efficient catalysis of chlorophenol. Reaction pathways are proposed based on the relative time of oxidation products formation.
Journal of Molecular Catalysis A: Chemical, 2006
ABSTRACT Photolysis of aqueous solutions of chlorophenols (4-chlorophenol, 2,4-dichlorophenol, 2,... more ABSTRACT Photolysis of aqueous solutions of chlorophenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and pentachlorophenol) in the presence of immobilized non-transition metal phthalocyanine photosensitizers onto Amberlite® is presented. The photosensitizers studied are: Al (AlOCPc) and Zn (ZnOCPc) octacarboxyphthalocyanines; Al (AlPcS4) and Zn (ZnPcS4) tetrasulfophthalocyanines; sulfonated phthalocyanine complexes (containing mixtures of differently substituted derivatives) of Al (AlPcSmix), Zn (ZnPcSmix), Ge (GePcSmix), Si (SiPcSmix) and Sn (SnPcSmix). Photolysis of the chlorophenols resulted mainly in the formation of chlorobenzoquinone derivatives. The complexes showed order of activity towards the transformation of pentachlorophenol as follows: ZnOCPc>SiPcSmix>SnPcSmix>ZnPcSmix>GePcSmix>ZnPcS4>AlPcSmix>AlOCPc>AlPcS4. The generation of singlet oxygen (1O2) by these immobilized MPc photosensitizers was found to play a major role in their photoactivities towards the transformation of these chlorophenols. Langmuir–Hinshelwood (L–H) kinetic model studies showed that the ZnOCPc, GePcSmix and ZnPcSmix photocatalysis occurred on the catalysts surface.
Journal of Colloid and Interface Science, 2004
The redox activities of water-soluble iron͑II͒ tetrasulfophthalocyanine ͑FeTSPc͒ and single-walle... more The redox activities of water-soluble iron͑II͒ tetrasulfophthalocyanine ͑FeTSPc͒ and single-walled carbon nanotube-poly͑m-aminobenzene sulfonic acid͒ ͑SWCNT-PABS͒ adsorbed on a gold surface precoated with a self-assembled monolayer ͑SAM͒ of 2-dimethylaminoethanethiol ͑DMAET͒ have been described. Atomic force microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy were employed to probe the buildup and formation of their thin solid films on the gold surface. The solid films exhibited excellent electrochemical stability. The electrode based on the mixed hybrids ͑Au-DMAET-SWCNT-PABS/FeTSPc͒ exhibited the fastest electron transport ͑k o Ϸ 0.4 cm s −1 ͒ compared to other electrodes ͑ϳ0.2 cm s −1 ͒, suggesting the ability of the SWCNT-PABS to act as efficient conducting species that facilitate electron transport between the integrated FeTSPc and the underlying gold substrate. Given the paucity of literature in the SAMs of water-soluble phthalocyanine complexes, the proposed fabrication strategy could potentially be extended to other water-soluble metallophthalocyanines and related organometallic complexes.
... on Fluorine Doped SWCNT Template: A Novel and Smart Electrode Material for Li-Ion Battery. [E... more ... on Fluorine Doped SWCNT Template: A Novel and Smart Electrode Material for Li-Ion Battery. [ECS Meeting Abstracts 1003, 603 (2010)]. Bolade O. Agboola, HongzeLuo, Kenneth I. Ozoemena, Lukas Le Roux, Mkhulu Mathe.
... Coated Lithium Manganese Oxide Dispersed on Carbon Nanotubes. [ECS Meeting Abstracts 1003, 59... more ... Coated Lithium Manganese Oxide Dispersed on Carbon Nanotubes. [ECS Meeting Abstracts 1003, 598 (2010)]. Kenneth I. Ozoemena, Tendamudzimu Ramulifho, Bolade O. Agboola, Hongze Luo, Lukas Leroux, Mkhulu Mathe.
Al/F Surface Modified Single Crystalline Spinel LiMnO Nanowires/Nanorods as Cathode Material for ... more Al/F Surface Modified Single Crystalline Spinel LiMnO Nanowires/Nanorods as Cathode Material for Li-Ion Battery. [ECS Meeting Abstracts 1003, 616 (2010)]. Hongze Luo, Bolade O. Agboola, Kenneth I. Ozoemena, Lukas Le Roux, Mkhulu Mathe.
Energy & Environmental Science, 2010
The supercapacitive properties of nickel(II) tetraaminophthalocyanine (NiTAPc)/multi-walled carbo... more The supercapacitive properties of nickel(II) tetraaminophthalocyanine (NiTAPc)/multi-walled carbon nanotube (MWCNT) nanocomposite films have been interrogated for the first time and found to possess a maximum specific capacitance of 981 AE 57 F g À1 (200 AE 12 mF cm À2 ), a maximum power density of 700 AE 1 Wkg À1 , a maximum specific energy of 134 AE 8 Wh kg À1 and excellent stability of over 1500 charge-discharge continuous cycling. Impedimetric study proves that most of the stored energy of the MWCNT-NiTAPc nanocomposite can be accessible at high frequency (720 Hz). When compared to MWCNTs modified with unsubstituted nickel(II) phthalocyanine (MWCNT-NiPc) or nickel(II) tetratert-butylphthalocyanine (MWCNT-tBuNiPc), MWCNT-NiTAPc exhibited superior supercapacitive behaviour, possibly due to the influence of nitrogen-containing groups on the phthalocyanine rings.
Electrochimica Acta, 2006
Nickel tetrakis(benzylmercapto)phthalocyanine (NiTBMPc) and nickel tetrakis(dodecylmercapto)phtha... more Nickel tetrakis(benzylmercapto)phthalocyanine (NiTBMPc) and nickel tetrakis(dodecylmercapto)phthalocyanine (NiTDMPc) complexes were synthesized and their spectral and electrochemical properties reported. The CV showed four or five redox processes for NiTBMPc and NiTDMPc, respectively. For the first time, spectroelectrochemistry gave evidence for the formation of Ni II /Ni I process in a NiPc complex. The rest of the processes were ring based. The NiTBMPc complex was successfully deposited on both gold and glassy carbon electrodes by electropolymerisation while NiTDMPc complex was deposited on gold electrode only. The films were electrotransformed in aqueous 0.1 M NaOH solution to the O-Ni-O oxo bridged form. The modified electrodes were characterized using electrochemical impedance spectroscopy and the results showed typical behavior for modified electrodes. Electrodes with poly-Ni(OH)Pcs films exhibited higher charge transfer resistance values, R p than their corresponding poly-NiPcs films counterparts. All the modified electrodes showed improved catalytic activities than the unmodified electrodes towards nitrite ions electrooxidation. Better catalytic activities were observed for the modified electrodes when they were transformed to O-Ni-O oxo bridge form. All the modified electrodes exhibited high resistance to electrode surface passivation.
Electrochimica Acta, 2007
ABSTRACT This work reports on the use of nickel(II) tetrakis benzylmercapto (NiTBMPc) and dodecyl... more ABSTRACT This work reports on the use of nickel(II) tetrakis benzylmercapto (NiTBMPc) and dodecylmercapto (NiTDMPc) metallophthalocyanine complexes films on gold electrodes for the electrochemical oxidation of 4-chlorophenol (4-CP) and 2,4,5-trichlorophenol (TCP). Both NiTBMPc and NiTDMPc complexes were successfully deposited on gold electrodes by electropolymerisation. The films were electro-transformed in aqueous 0.1 M NaOH solution to the ‘O–Ni–O oxo’ bridged form. For both complexes, films with different thickness were prepared and characterised by electrochemical impedance and UV–vis (on indium tin oxide) spectroscopies and the results showed typical behaviour for modified electrodes with increasing charge transfer resistance values (Rp) with polymer thickness. The poly-Ni(OH)NiPcs showed better catalytic activity than their poly-NiPcs counterparts.
Electrochemistry Communications, 2009
Electrochemical behaviour of self-assembled monolayer of 2-dimethylaminoethanethiol (DMAET) on go... more Electrochemical behaviour of self-assembled monolayer of 2-dimethylaminoethanethiol (DMAET) on gold electrode, with and without integration with SWCNT-poly(m-aminobenzene sulphonic acid) (SWCNT-PABS) has been probed. It is proved that the so-called electric field induced protonation-deprotonation process, hitherto observed for the -COOH terminated SAMs, is also observed for the -N(H) + (CH 3 ) 2 terminated. The surface pK a of DMAET was estimated as 7.6, smaller than its solution pK a of 10.8. It is also shown that SWCNT-PABS is irreversibly attached to the DMAET SAM.
Electrochemistry Communications, 2007
Voltammetric characterisations of cobalt, iron, manganese, nickel and zinc phthalocyanine complex... more Voltammetric characterisations of cobalt, iron, manganese, nickel and zinc phthalocyanine complexes tetra substituted with benzyl-and dodecyl-mercapto ring substituents and immobilisation on gold electrodes via the self-assembling technique are presented. The self-assembled films are stable and showed blocking characteristics towards the following Faradaic processes; gold surface oxidation, under potential deposition of copper and solution redox chemistry of . The solution chemistry of [Fe(CN) 6 ] −3 /[Fe(CN) 6 ] −4 redox process was used to study the orientation of the CoPcs-SAMs and this revealed a possible deviation from flat orientation of the complexes on the gold electrodes when the SAM formation times were greater than 24 h. For SAM formation time at 24 and 48 h, CoTDMPc-SAM showed more inhibition of the [Fe(CN) 6 ] −3 /[Fe(CN) 6 ] −4 redox process than the CoTBMPc-SAM counterpart, indicating more blocking characteristics of the dodecylmercapto ring substituents compared to the benzylmercapto counterpart. To avoid SAM desorption, the potential application should be limited to −0.2 to +0.8 V vs. Ag AgCl (NaCl, sat'd) in acidic and neutral pH.