Applications of polymerized metal tetra-amino phthalocyanines towards hydrogen peroxide detection

Abstract

This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H 2 O 2 ). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymermodified ITO surfaces. The electrocatalytic reduction of H 2 O 2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H 2 O 2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H 2 O 2 were of the order of 10 -7 M, with high sensitivity ranging from 6.0-15.4 mA.mM -1 .cm -2 .APPlICAtIOnS Of POlymerIzeD metAl tetrA-AmInO PhthAlOCyA nIneS 253MPc-modified electrodes are their ability to form stable polymers on electrode surfaces [6-13, 24] and long shelflife. We have previously reported [4] on the use of CoPc derivative-modified gold electrodes using self-assembly monolayer method (SAM) for the detection and monitoring of H 2 O 2 with detection limits of 1 × 10 -7 M and a reduction potential of -0.2 V vs. Ag|AgCl. SAMs on gold electrodes desorbs from the electrode at high pH, allowing only narrow potential range to be used [21]. CoPc-, MnPc-and FePc-modified screen-printed carbon electrodes (SPCE) have been employed for the detection of hydrogen peroxide with electrochemical reduction potential of -0.35 V vs. Ag|AgCl [20]. There is a need to lower both the detection limit and reduction potential for hydrogen peroxide without the use of unstable enzyme electrodes. The MPc complexes studied in this work contain cobalt and manganese as metal ion centers and these complexes are known to exhibit excellent electrocatalytic activity [25][26][27][28][29][30]. The amino functionalities on the phthalocyanine macrocycle were chosen due to their known ease of forming polymers on electrode surfaces [12,13,24], which are more stable for analysis compared to SAMs. The electrocatalytic and electroanalytical properties of gold and glassy carbon electrodes modified with thin polymeric films of CoTAPc and MnTAPc are compared for electroreduction of H 2 O 2 .

Electrocatalytic Activity of Nanocomposites of Sulphur Doped Graphene Oxide and Nanosized Cobalt Phthalocyanines

“…Hydrogen peroxide is employed as an example since its electrocatalysis on phthalocyanines is known . A number of techniques have been employed in the detection of hydrogen peroxide including fluorescent probes and electrochemical methods . Most of the electrochemical probes used to detect hydrogen peroxide utilise electroreduction.…”

“…This work focuses on the investigation of the electrocatalytic behaviour of electrodes modified with nanocomposites of sulphur doped graphene oxide nanosheets (SDGONS) with nanosized unsubstituted cobalt phthalocyanine (CoPc NP ) and cobalt tetra amino phthalocyanine (CoTAPc NP ) (the structures of the phthalocyanines are shown in Figure ). Cobalt phthalocyanines are well known for their electrocatalytic behaviour towards a number of analytes including hydrogen peroxide which is employed in this work. Nanosized phthalocyanines have been reported to have improved electrocatalytic behaviour as compared to their bulk counterparts hence the choice of the former in this work .…”

“…This is the first time that S doped GONS are employed for electrocatalysis of hydrogen peroxide. Hydrogen peroxide is employed as an example since its electrocatalysis on phthalocyanines is known . A number of techniques have been employed in the detection of hydrogen peroxide including fluorescent probes and electrochemical methods .…”

“…This work focuses on the investigation of the electrocatalytic behaviour of electrodes modified with nanocomposites of sulphur doped graphene oxide nanosheets (SDGONS) with nanosized unsubstituted cobalt phthalocyanine (CoPcNP)a nd cobalt tetra amino phthalocyanine (CoTAPcNP)( the structures of the phthalocyanines are shown in Figure1). Cobalt phthalocyanines arew ell known for their electrocatalytic behaviourt owards an umbero fa nalytes includingh ydrogen peroxide [14] which is employed in this work. Nanosized phthalocyanines have been reported to have improved electrocatalytic behaviour as compared to their bulk counterparts hence the choice of the former in this work [15][16][17].T he combination of the two electrocatalysts:n anosized phthalocyanines and SDGONS is expected to improve electrocatalytic activity.W eh ave recently shownt hat the combination of phthalocyanines and un-doped GONS show improved electrocatalytic behaviour [18,19].T here is only one studyi nvolving doped (N) GONS for electrocatalysis [17] of hydrogen peroxide.T his is the first timet hat S doped GONSa re employed for electrocatalysis of hydrogen peroxide.H ydrogenp eroxide is employed as an example sincei ts electrocatalysiso np hthalocyanines is known [14].An umber of techniques have been employed in the detection of hydrogenp eroxidei ncluding fluorescentp robes [20][21][22] and electrochemical methods [14,23,24].M ost of the electrochemical probes used to detect hydrogen peroxide utilise electroreduction.…”

Electrocatalytic activity of bimetallic Au–Pd nanoparticles in the presence of cobalt tetraaminophthalocyanine

“…The list of electrodes employed in this work is shown in Tables 1 and 2. CoTAPc was used because it is known to exhibit excellent electrocatalytic activity toward oxidation and reduction of a wide range of chemical substances [23][24][25]. The modified electrodes containing bimetallic nanoparticles and poly-CoTAPc are tested for electrochemical oxidation of hydrazine as a test analyte.…”