Carbon Nanotube-Conducting Polymer Composites as Electrode Material in Electroanalytical Applications

This chapter gives a brief overview of the preparation, characterization, and analytical applications for combinations of polymers and carbon nanotubes (CNTs) that have been prepared in different ways, which are used as an electrode material. For this purpose, multiwalled or single-walled CNTs are composed of different types of conductive polymers. The preparation of CNT-conducting polymer composite electrodes was explained by their deposition order. Chemical and morphological surface characterizations of composite electrodes were presented by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. In addition, CNT-based polymer composite electrode usage in sensor applications for trace organic/inorganic compounds and energy applications is discussed in the last part of this chapter

The sensitive determination of ascorbic acid and routine separately and simultaneously by polarographic method

Polarographic behaviour of ascorbic acid and rutin depending on the pH, concentration were investigated.The polarographic pKa of Rutin was found as 7.9. The determination of ascorbic acid and rutin were carried out at pH = 7(the determination range, 2.10- 5- 4.10" 4M for ascorbic acid and 2.10" 5- 2.10" 4 M for rutin) by direct polarographic method, and also simultaneous determination was carried out at the same conditions. In the presence of periodate, the indirect polarographic method was used for the determination of ascorbic acid and rutin or their mixtures.The ten fold sensitive results were taken according to the direct method. A relaible and sensitive indirect polarographic method was developed for ascorbic acid or rutin their mixtures.Askorbik asit ve rutin'in pH, konsantrasyon'a bağlı olarak polarografik davranışı incelenmiştir. Rutin için polarografik pKa 7.9 olarak bulundu. Askorbik asit ve rutin pH=7'dedirekt polarografik metotla (askorbik asit için 2.1 0"5 - 4.1 0-4 M ve rutin için 2.1 0-5 - 2.1 0"4 M arasında lineer değişim bulunmuştur), periodat varlığında ise, askorbik asit, rutin ve bunların karışımları indirekt polarografik yöntemle tayin edilmiştir. Direkt yönteme göre on kat duyar sonuçlar alınmıştır. Askorbik asit, rutin ve karışımları için güvenilir ve duyar indirekt* .., polarografik yöntem geliştirilmişti

Preparation and investigation of modified electrodes and applications to the new voltammetric techniques

In this study, the voltammetric and amperometric flow injection (FIA) behaviour of rotating glassy carbon (RGC), carbon paste (CP) and CP modified with copper(I) oxide (QfcO) or copper phthalocyanine (CuPc) electrodes was investigated in the presence of ascorbic acid (AA) or cysteine (oxidizable) and periodate (reducable) compounds. The RGCE was used for the direct determination of AA or periodate by measuring the anodic or cathodic waves respectively. Indirect AA determination was carried out in the presence of excess periodate by measuring the decrease of the first reduction wave of periodate. It was shown that 3.0 mole periodate was consumed per mole of AA. AA, periodate or AA-periodate mixtures were also studied using amperometric FIA technique. The voltammetric behaviour of modified electrodes was investigated in different buffer solutions and in the presence of AA, periodate or cystein. When the CPE modified with Q12O was used, the peak heightsat - 0.07 V at pH 7.00 in phosphate buffer, and at - 0.70 V at pH 9.20 in borate buffer linearly increased in the concentration range 1.0.10"9- 2.0.10"8 M or 2.0.10"9-3.0.10"8 M AA or cystein respectively. When the voltammetric behaviour of the CPE modified with CuPc was studied, AA, periodate or cystein were used. The peak heights at + 0.28 V, + 0.18 V on pH 4.76 acetate buffer or -1.08 V in borate buffer linearly increased with increasing AA, periodate or cysteine concentration in the range 5.0 İO^.O.IO"4, 1.0.10-5-5.0.10-4or2.0.10"10-2.0. 10-9 M respectively. When the results were compared with the RGCE or the CPE, the most sensitive and reproducible results were found with modified electrodes. The CPE modified with CuPc was also applied to FLA. AA and periodate were determined at the nanogram level and at an injection rate of 200-240 samples per hour. Keywords: Modified electrodes, ascorbic acid, periodate, cystein, flow injection analysis.Bu çalışmada, döner camımsı karbon (RGC), karbon pasta (CP) ve bakır ftalosyanin (CuPc) veya bakır(I) oksit (Cu20) ile modifiye karbon pasta elektrotların voltametrik ve akışkan sistemlerde (FIA) amperometrik davranışları askorbik asit (AA) ve sistein(yükseltgenebilen), periyodat (indirgenebilen) maddeler varlığında incelenmiştir. RGCE ile AA ve periyodat'ın doğrudan tayinleri sırasıyla anodik ve katodik akımlanndan yaralanarak gerçeMeştirilmiştir. Ayrıca aşırı periyodat ortamında, AA- periyodat tepkimesi ile AA'in dolaylı tayini periyodatın I. indirgenme dalgasındaki azalmadan gidilere voltametrik incelemesinde AA'in yaklaşık 3 mol periyodat harcadığı bulunmuştur. FIA amperometrik teknik ile AA, periyodat ve AA-periyodat tepkimesi incelenmiş AA ve periyodat tayinleri gerçeldeştirilmiştir. Modifiye elektrodlann voltametrik davranışları ise değişik tampon çözelti ortamlarında ve AA, sistein veya periyodat varlığında incelendiğinde, Cu20 ile modifiye CPE'nin pH 7.00 fosfat tampon çözeltisinde -0.07 V daki piki 1.0.1 0-9- 2.0.1 0"8 M ve pH 9.20 borattampon çözeltisinde -0.70 V daki piki ise 2.0.10"9-3.0.10"8 M derişim aralıklarında sırasıyla AA ve sistein ile doğrusal değişim göstermiştir. CuPc ile modifiye CPE ise pH 4.76 asetat tampon çözeltisinde + 0.28 V daki pik AA, + 0.18 V daki pik periyodat ve pH 9.20 borat tampon çözeltisinde ise - 1,08 V daki pik sistein varlığında, sırasıyla 5.0 10"7- 2.0 10-4 M, 1.0.105-5.0.10"5 M ve 2.0.10-'°-2.0.10-9 M derişim aralıklarında doğrusal değişimler göstermiştir. Modifiye elektrodlar ile elde edilen sonuçlar GCE ve CPE sonuçlan ile karşilaştınldıgında, modifiye elektrodlar ile her üç inceleme maddesi için duyarlık ve tekrarlanabilirliğin arttığı bulunmuştur. CuPc modifiye CPE yeni voltametrik teknik olarak FIA' ya uygulanmiş, AA ve periyodat nanogram düzeyinde saatte 200- 240 enjeksiyon hızıyla tayin edilebilmiştir

Fabrication of Co3O4 particles-modified multi-walled carbon nanotube and poly(phenosafranine) composite electrode for selective and sensitive rutin detection

The preparation and characterisation of a new composite electrode with Co3O4 particles-modified multi-walled carbon nanotube (MWCNT) and poly(phenosafranine), as well as its novel application for the voltammetric detection of rutin was described. The resulting composite electrode was characterised using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). In the optimised experimental conditions, the oxidation peak current (I-pa) of rutin showed a linear increase in concentration, between 0.008-0.6 and 0.80-6.0 ; mu;mol L-1, with a detection limit of 0.00379 ; mu;mol L-1. Due to its good selectivity and stability, the composite electrode was successfully applied in detecting rutin in pharmaceutical formulations.Ege University Research Funds, Grant/Award Number:FDK-2020-21471Ege University Research Funds [FDK-2020-21471

Preparation and characterization of metal oxide nanopArticles modified carbon nanotube-conducting polymers based composite electrode for simultaneous determination of melatonin and caffeine

In this thesis study, highly effective zincoxide metal nano pArticles electrodeposited by chronoamperometry on multi-walled carbon nanotube and polycresol red film based composite modified surfaces were prepared onto glassy carbon electrode surfaces and after the examination of morphological, chemical and electrical properties of these modified electrodes, the electrochemical behavior of melatonin and caffeine was investigated at different pHs. When peak currents and peak potentials of melatonin and caffeine were compared at bare and prepared composite electrodes, it was determined that the optimum working pH was obtained as 7.0 by using phosphate buffer. Moreover, when the behavior of all electrodes against melatonin and caffeine oxidation was examined in pH 7.0 phosphate buffer solutions, zincoxide-multi-walled carbon nanotube-polycresol red composite electrode (ZnO/MWCNT/PCR/GCE) was observed to have the highest activity. Regarding to the formation of polycresol on the electrode surface, cresol red concentration and number of cyclic voltammetric cycles were optimized. Then, zincoxide optimization parameters such as concentration, deposition of potential and deposition time were studied respectively. After the optimization of experimental conditions, experimental studies for the sensitive detection of melatonin and caffeine were highlighted utilizing at bare GC, PCR/GC, MWCNT/PCR/GC, MWCNT/GC, ZnO/MWCNT/GC ve ZnO/MWCNT/PCR/GC electrodes by performing differential pulse voltammetry technique and when the obtained data was compared to each other, finally ZnO/MWCNT/PCR/GC composite electrode has the highest activity. For this electrode, linear range was found to be 4.0x10-8 M– 4.0x10-7 M for melatonin and caffeine, while limit of detection was calculated as 1.38x10-8 M and 1.33x10-8 M (S/N=3), respectively.Bu tez çalışması kapsamında, camımsı karbon elektrot yüzeyine sırasıyla elektropolimerizasyon ile polikresol kırmızısı döngüsel voltammetri ile film oluşturularak, oluşan film yüzeyi üzerine çok duvarlı karbon nanotüp ve çok duvarlı karbon nano tüp üzerine çinko oksit metal nano parçacıkları kronoamperometri ile elektrokimyasal olarak depolanmıştır. Oluşturulan kompozit modifiye elektrotların morfolojik, kimyasal ve elektriksel yüzey özellikleri aydınlatıldıktan sonra, melatonin ve kaffeinin tekli ve bir arada olduğu koşullardaki elektrokimyasal davranışı farklı pH'larda incelenmiştir. Yalın ve kompozit elektrotlarda melatonin ve kaffeinin pik akım yüksekliği ve pik potansiyelleri karşılaştırıldığında en uygun çalışma pH'ının 7.0 fosfat tamponu olduğu saptanmıştır. Aynı zamanda pH=7.0 fosfat tamponu ortamında tüm elektrotların melatonin ve kaffein yükseltgenmesine davranışları incelendiğinde, polikrezol kırmızısı-çok duvarlı karbon nanotüp-çinko oksit depolanmış kompozit elektrodun (ZnO/MWCNT/PCR/GCE) en yüksek katalitik etkinliğe sahip olduğu saptanmıştır. Polikrezol kırmızısının elektrot yüzeyinde oluşturulmasına ilişkin, krezol kırmızısı derişimi ve döngüsel voltammetrik döngü sayısı optimize edilmiştir. Ardından MWCNT/PCR/GCE üzerine kronoamperometri ile depolanan çinko oksit metal nano parçacıklarının sırasıyla derişim, potansiyel ve biriktirme süresine ilişkin optimizasyon çalışmaları gerçekleştirilmiştir. Optimum deney koşulları saptandıktan sonra, differansiyel puls voltammetrik teknikle melatonin ve kaffeinin duyar tayinine yönelik deneysel çalışmalar yalın camımsı (GC), PCR/GC, MWCNT/PCR/GC, MWCNT/GC, ZnO/MWCNT/GC ve ZnO/MWCNT/PCR/GC elektrotlarıyla yapılmış ve elde edilen veriler karşılaştırıldığında, en yüksek etkinliğe sahip olan elektrodun kompozit yapıdaki ZnO/MWCNT/PCR/GC elektrodu olduğu saptanmıştır. ZnO/MWCNT/PCR/GC kompozit elektrotta pik akım yüksekliğinin melatonin ve kaffein derişimi ile değişimi 4.0x10-8 M – 4.0x10-7 M aralığında doğrusal bulunurken, belirtme alt sınırı ise sırasıyla 1.38x10-8 M ve 1.33x10-8 M olarak saptanmıştır (S/N=3). Hazırlanan kompozit elektrotların, morfolojisi taramalı elektron mikroskobu, yüzeyin kimyasal bileşenleri X-ışını fotoelektron spektroskopisi ve elektriksel özellikleri ise elektrokimyasal impedans tekniği ile aydınlatılmıştır

Au-Pt bimetallic nanoparticles anchored on conducting polymer: An effective electrocatalyst for direct electrooxidation of sodium borohydride in alkaline solution

This work proposes Au-Pt nanoparticles decorated poly(p-aminophenol) (PAP) film on a glassy carbon electrode for direct electrochemical oxidation of sodium borohydride. The Au-Pt bimetallic surfaces were prepared with two electrodeposition procedures which are the simultaneous electro-deposition (1-Au-Pt/PAP/GCE) and the successive electro-deposition (2-Au-Pt/PAP/GCE) procedures. The catalysts were used for the investigation of borohydride electrochemical oxidation and compared catalytic activities by CV, RDEs and chronoamperometric techniques. AFM, SEM, XPS, XRD and CV were used to identify of the structural and morphological properties of the developed modified surfaces. The results of electrochemical measurements indicated that simultaneous electro-deposition of Au-Pt to the polymer structure significantly shifted negative oxidation potential and in-creases the current density of borohydride electrochemical oxidation. The exchange electron number of 1-Au-Pt/ PAP/GC and 2-Au-Pt/PAP/GC electrodes were calculated as 7.8 and 6.7, respectively. This approves the strong tendency of the 1-Au-Pt/PAP catalyst toward effective direct electrochemical oxidation of NaBH4 in an alkaline medium.This work was supported by the Scientific and Technical Research Council of Turkey (TUBITAK) with 110 T806 project number and Ege University Research Funds (BAP project, 10 FEN/075) .Scientific and Technical Research Council of Turkey (TUBITAK) [110 T806]; Ege University Research Funds (BAP project) [10 FEN/075

Enhanced electrocatalytic oxidation of methanol on Au-Pt bimetallic particles modified copper phthalocyanine-carbon nanotube composite electrode

In this work, we prepared modified copper phthalocyanine-carbon nanotube (CuPc-CNT) catalysts containing bimetallic (Au-Pt, Au/Pt, Pt/Au) and monometallic nanoparticles (Au or Pt), using a simple electrochemical technique. We investigated the catalyst structural and physical properties by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and electrochemical impedance spectroscopy. The bimetallic systems (Au-Pt/CuPc-CNT > Pt/Au/CuPc-CNT > Au/Pt/CuPc-CNT) proved to have a better current density towards methanol oxidation than that of mono-metallic systems (Pt/CuPc-CNT > Au/CuPc-CNT) in alkaline media. The electrochemical surface area (ECSA) of Au-Pt/CuPc-CNT was found to be 60.25 m(2) g(-1). The methanol oxidation reaction took place with the electron transfer, followed by the catalytic chemical reaction. Thus, the electrochemically-prepared Au-Pt/CuPc-CNT catalyst of the highest stability and enhanced electrocatalytic activity towards methanol oxidation represents a promising candidate for use in alkaline direct methanol fuel cells

Fabrication of nickel coated graphene oxide composite electrode for sensitive determination of Rutin

WOS: 000431158000010Nickel nanoparticles incorporated with graphene oxide composite-glassy carbon electrode (Ni-GO/GCE) was constructed via a facile electrochemical method for sensitive and selective determination of rutin. The surface morphology, surface chemistry and conductance of the prepared electrodes were characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-Ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The electrochemical behaviour of rutin on the Ni-GO/GCE was investigated by using of cyclic voltammetry technique. The composite electrode was also used for the detection of rutin with square wave voltammetry. The results indicated that under optimized conditions, the anodic peak current (I-pa) of rutin was found to be proportional to its concentration over two linear ranges 1.1 x 10(-8)-1.0 x 10(-6) mol L-1 and 2.2 x 10(-6)-1.5 x 10(-5) mol L-1, and a low detection limit of 3.2 x 10(-9) mol L-1 was observed with the developed electrode. Interference studies were also performed in the presence of inorganic and organic compounds. Moreover, the Ni-GO/GCE was successfully applied for the determination of rutin in pharmaceutical formulations and remarkable sensitivity with acceptable recoveries were obtained.Ege University Research Funds (BAP Project)Ege University [16-EGEMATAL-001]This work was supported by Ege University Research Funds (BAP Project No: 16-EGEMATAL-001)