Oxidation Peak Potential Research Articles

Recognition of glutathione based on its electrocatalytic oxidation on the bare fluorine doped tin oxide electrode

We revealed that the bare fluorine doped tin oxide (FTO) exhibited the electrocatalytic ability towards the oxidation of glutathione (GSH) in a narrow pH region, which was examined using linear sweep voltammetry (LSV). LSV indicated that an oxidation peak of GSH at the FTO electrode occurs at 0.27V (vs. SCE) that is 0.77V negative of that at the bare Pt electrode, and GSH cannot be oxidized at the glassy carbon (GC) electrode in a potential region −0.40 to 1.20V, at pH4.4. On the basis of the electrocatalytic oxidation of GSH in a narrow pH region 4.0–5.5 and its lower oxidation peak potential, the bare FTO electrode can be used as a probe to recognize GSH from the 20 α-amino acids present in proteins, cystine, homocysteine, cysteamine, thiobenzoic acid, ascorbic acid, catechol, and dopamine. Its detection limit for the recognition of GSH is 5nM.

Pt nanoparticles/reduced graphene oxide nanosheets as a sensing platform: Application to determination of droxidopa in presence of phenobarbital

A simple electrochemical sensor has been developed based on the reduced graphene oxide/Pt nanoparticles nanocomposite immobilized on modified glassy carbon electrode (nPt-GN/GCE). The modified electrode displayed excellent electrochemical catalytic activities toward droxidopa (DDP) and phenobarbital (PB). The analytical performance of prepared electrode for the simultaneous determination of DDP and PB was investigated by using cyclic voltammetry and differential pulse voltammetry (DPV). The nPt-GN based sensor could separate the oxidation peak potentials of DDP and PB about 230mV by DPV method. The calculated detection limits, obtained by DPV, for DDP and PB were 3.1×10−8M and 2.36×10−8M, respectively. The fabricated sensor was successfully applied to the detection of DDP and PB in real samples. The experiments illustrate that nPt-GN nanocomposite is a worthy electrode material which offers a large surface-to-volume ratio and improves the selectivity and sensitivity.

Graphene-based hybrid for enantioselective sensing applications

Chirality is a major field of research of chemical biology and is essential in pharmacology. Accordingly, approaches for distinguishing between different chiral forms of a compound are of great interest. We report on an efficient and generic enantioselective sensor that is achieved by coupling reduced graphene oxide with γ-cyclodextrin (rGO/γ-CD). The enantioselective sensing capability of the resulting structure was operated in both electrical and optical mode for of tryptophan enantiomers (D-/L-Trp). In this sense, voltammetric and photoluminescence measurements were conducted and the experimental results were compared to molecular docking method. We gain insight into the occurring recognition mechanism with selectivity toward D- and L-Trp as shown in voltammetric, photoluminescence and molecular docking responses. As an enantioselective solid phase on an electrochemical transducer, thanks to the different dimensional interaction of enantiomers with hybrid material, a discrepancy occurs in the Gibbs free energy leading to a difference in oxidation peak potential as observed in electrochemical measurements. The optical sensing principle is based on the energy transfer phenomenon that occurs between photoexcited D-/L-Trp enantiomers and rGO/γ-CD giving rise to an enantioselective photoluminescence quenching due to the tendency of chiral enantiomers to form complexes with γ-CD in different molecular orientations as demonstrated by molecular docking studies. The approach, which is the first demonstration of applicability of molecular docking to show both enantioselective electrochemical and photoluminescence quenching capabilities of a graphene-related hybrid material, is truly new and may have broad interest in combination of experimental and computational methods for enantiosensing of chiral molecules.

Effects of the Electrodeposition Time in the Synthesis of Carbon-Supported Pt(Cu) and Pt-Ru(Cu) Core-Shell Electrocatalysts for Polymer Electrolye Fuel Cells

Pt(Cu)/C and Pt-Ru(Cu)/C electrocatalysts with core-shell structure supported on Vulcan Carbon XC72R have been synthesized by potentiostatic deposition of Cu nanoparticles on the support, galvanic exchange with Pt and spontaneous deposition of Ru species. The duration of the electrodeposition time of the different species has been modified and the obtained electrocatalysts have been characterized using electrochemical and structural techniques. The High Resolution Transmission Electron Microscopy (HRTEM), Fast Fourier Transform (FFT) and Energy Dispersive X-ray (EDX) microanalyses allowed the determining of the effects of the electrodeposition time on the nanoparticle size and composition. The best conditions identified from Cyclic Voltammetry (CV) corresponded to onset potentials for CO and methanol oxidation on Pt-Ru(Cu)/C of 0.41 and 0.32 V vs. the Reversible Hydrogen Electrode (RHE), respectively, which were smaller by about 0.05 V than those determined for Ru-decorated commercial Pt/C. The CO oxidation peak potentials were about 0.1 V smaller when compared to commercial Pt/C and Pt-Ru/C. The positive effect of Cu was related to its electronic effect on the Pt shells and also to the generation of new active sites for CO oxidation. The synthesis conditions to obtain the best performance for CO and methanol oxidation on the core-shell Pt-Ru(Cu)/C electrocatalysts were identified. When compared to previous results in literature for methanol, ethanol and formic acid oxidation on Pt(Cu)/C catalysts, the present results suggest an additional positive effect of the deposited Ru species due to the introduction of the bifunctional mechanism for CO oxidation.

Core-shell like Cu2O nanocubes enfolded with Co(OH)2 on reduced graphene oxide for the amperometric detection of caffeine

The authors report on the fabrication of Co(OH)2-enfolded Cu2O nanocubes on reduced graphene oxide (rGO), and the use of this material in an electrochemical caffeine sensor. The rGO/Cu2O/Co(OH)2 composite was characterized by X-ray powder diffraction pattern analysis, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and Raman spectroscopy. A rotating disc glassy carbon electrode covered with the nanocomposite displays enhanced electrocatalytic activity towards the electro-oxidation of caffeine. The peak oxidation potential is at 1.4 V (vs. Ag/AgCl) and hence is strongly shifted to the negative side when compared to other modified electrodes. The calibration plot is linear in the 0.83 to 1200 μM concentration range, with a 0.4 μM detection limit (at a signal-to-noise ratio of 3). The modified electrode is sensitive, selective and stable. It was successfully applied to the determination of caffeine in (spiked) caffeine-containing beverages and coffee powder and gave recoveries that ranged from 95.7 to 98.3 %.

Synthesis of CdO nanoparticles using direct chemical precipitation method: Fabrication of novel voltammetric sensor for square wave voltammetry determination of chlorpromazine in pharmaceutical samples

ABSTRACTA chemically modified electrode was constructed and applied to the electrooxidation of the chlorpromazine (CPZ). The oxidation peak potential of the CPZ at a surface of CdO/nanoparticles (NPs) ionic liquid carbon paste electrode (CdO/NPs/IL/CPE) appeared at 695 mV. The CdO/NPs were characterized with different methods such as transmission electron microscope and X-ray diffraction. Under optimized (pH 7.0), linear calibration curves were obtained in the range of 0.1–350 µM for CPZ, which shows adequate for the quantification in real samples. The proposed method was successfully applied to the determination of CPZ in both pharmaceutical and urine samples.

Electrogenerated chemiluminescence of cyclometalated iridium(III) complexes with derived β-acetylacetone as ancillary ligand

Two cyclometalated iridium(III) complexes, (pq)2Ir(sa) and (pq)2Ir(psa), with 2-phenylquinoline (pq) as the C^N main ligand and succinylacetone (sa) or 4,6-dioxo-6-phenylhexanoic acid (psa) as the O^O ancillary ligand, were synthesized at first time. The solubility was reached down to 0.1mM for (pq)2Ir(sa) and 10μM for (pq)2Ir(psa) in acetonitrile-water (v/v=5:95) solution. The photophysical, electrochemical and electrogenerated chemiluminescence (ECL) properties of (pq)2Ir(sa) and (pq)2Ir(psa) in acetonitrile were mainly investigated. The oxidation peak potential of (pq)2Ir(sa) and (pq)2Ir(psa) appears at +0.79V and +0.8V vs SCE. (pq)2Ir(sa) and (pq)2Ir(psa) display orange ECL emission with a maximum wavelength at 621nm and 610nm, respectively. ECL efficiencies of (pq)2Ir(sa) and (pq)2Ir(psa) in acetonitrile containing tripropylamine were calculated to be 21.3-folds and 35.4-folds higher than that of Ru(bpy)32+. It was surprised to find that small amount of water can greatly increase the ECL intensity of these two complexes in acetonitrile containing tripropylamine. The ECL methods for the determination of trace water in organic solvent were developed in the range from 0.02 to 4.0% (v/v) and 0.05 to 4.0% (v/v) with detection limit of 0.01% and 0.03% for (pq)2Ir(sa) and (pq)2Ir(psa), respectively. It was found that the O^O ancillary ligand played a key function in the water-enhanced ECL emission. A double coreactant ECL pathway is proposed for the water-enhanced ECL emission. This work demonstrates that (pq)2Ir(sa) and (pq)2Ir(psa) have lower potential and high ECL coefficient, which are promising for the effective use as ECL emitter in analytical application.

Synthesis of 5-[(2-hydroxynaphthalen-1-yl)diazenyl]isophthalic acid and its application to electrocatalytic oxidation and determination of adrenaline, paracetamol, and tryptophan

In this study, Au nanoparticles/poly 5-[(2-hydroxynaphthalen-1-yl)diazenyl] isophthalic acid film modified glassy carbon electrode (AuNPs/poly(NDI)/GCE) has shown excellent electrocatalytic activity toward the oxidation of adrenaline (ADR), paracetamol (PAC), and tryptophan (Trp). The bare glassy carbon electrode (GCE) fails to separate the oxidation peak potentials of these molecules, while the poly(NDI) film modified electrode can resolve them. Electrochemical impedance spectroscopy (EIS) indicates that the charge transfer resistance of the bare electrode decreases as 5-[(2-hydroxynaphthalen-1-yl)diazenyl] isophthalic acid is electropolymerized on the bare electrode. Furthermore, EIS exhibits enhancement of electron transfer kinetics between analytes and the electrode after electrodeposition of Au nanoparticles. Differential pulse voltammetry results show that the electrocatalytic current increases linearly in the ranges of 0.01–680.0μmolL−1 for ADR, 0.05–498.0μmolL−1 for PAC, and 3.0–632.0μmolL−1 for Trp; with detection limits (S/N=3) of 0.009μmolL−1, 0.005μmolL−1, and 0.09μmolL−1 for ADR, PAC, and Trp, respectively. The proposed method has been successfully applied for simultaneous determination of ADR, PAC, and Trp in biological samples.

Sensitive determination of caffeine by copper sulphide nanoparticles modified carbon paste electrode

Copper sulphide nanoparticles (CuS NPs) were synthesized by simple co-precipitation method in aqueous media using starch as a biopolymer. The obtained product was characterized by XRD, SEM, EDX, TEM, FTIR and UV–vis techniques. The particle size was determined by TEM analysis and found to be in the range 20–50nm. CuS NPs modified carbon paste electrode (CuS NPs MCPE) was employed to determine caffeine (CAF) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The CuS NPs MCPE showed better electrocatalytic activity towards the oxidation of CAF, which was confirmed by enhance in the oxidation peak current and decrease in oxidation peak potential. Furthermore, in electrochemical impedance (EI) studies, the charge transfer resistance (RCT) at CuS NPs MCPE (12.1kΩ) decreases as compared to bare CPE (42.6kΩ), which suggests that CuS NPs improves the charge transfer capacity of CPE. Electron transfer kinetic parameters, sensitivity and surface active area of the electrode were determined. Under experimental conditions, the oxidation current of CAF was proportional to its concentration from 2μM to 120μM. The detection limit was found to be 18×10−9M. The developed method was successfully applied to determine CAF content in food samples with appreciable results.

Study on glutathione’s inhibition to dopamine polymerization and its application in dopamine determination in alkaline environment based on silver selenide/molybdenum selenide/glassy carbon electrode

Cellular glutathione plays critical roles in protecting neuronal cells against dopamine induced oxidative stress and electrophilic cellular damage; inspired by above mentioned properties of glutathione, we used glutathione as a polymerization inhibitor to develop a dopamine biosensor which can be used in alkaline environment. The detection of dopamine in alkaline environment has been challenged by its polymerization for many years, glutathione as a kind of thiol can be used to prevent the polymerization of dopamine in alkaline environment by eliminating the electrophilic quinone molecules needed during the polymerization. In order to enhance the electrochemical performance of electrode, Ag2Se/MoSe2 composite with large exposed surface areas was synthesized, which improved the sensitivity and stability for dopamine detection. The low oxidation peak potential for dopamine, 0.04V vs. SCE, indicats that glutathione can realize the electrooxidation of dopamine at lower potential in alkaline environment. In this study, by introducing glutathione to inhibit the dopamine polymerization, sensitive and stable detection of dopamine can be achieved at pH 8.5 based on the Ag2Se/MoSe2/GCE.

Highly sensitive electrochemical capsaicin sensor based on graphene-titania-Nafion composite film

A highly sensitive electrochemical capsaicin sensor utilizing graphene-doped sol-gel titania-Nafion composite film modified glassy carbon electrode (GCE) is presented. The composite modified GCE is characterized by scanning electron microscopy and its electrochemical properties by electrochemical impedance spectroscopy and cyclic voltammetry. The composite modified GCE facilitates the direct adsorption of capsaicin on the electrode surface via π-π interaction between capsaicin and graphene. Furthermore, the present composite modified electrode not only significantly enhances the oxidation peak current, but also decreases its oxidation peak potential, indicating that the graphene in the titania-Nafion composite clearly exhibits good electocatalytic ability to oxidize capsaicin. Under the optimized conditions, the present electrochemical sensor shows a linear response to capsaicin from 0.03 to 10.0μM with a remarkably low detection limit of 8.6nM (S/N=3), which is much lower compared to those obtained with previously reported electrochemical sensors. The recovery tests performed for spiked capsaicin in real samples such as Korean hot pepper and red pepper flakes are satisfactory. Thus, the present capsaicin electrochemical sensor could be implemented as a replacement for the human-subjective Scoville organoleptic test, and can also be further developed as a sensitive portable electrochemical sensor for the determination of capsaicin in food and pharmaceuticals.

Fabrication of novel electrochemical sensor for determination of vitamin C in the presence of vitamin B9 in food and pharmaceutical samples

Synthesis and application of NiO-multiwall carbon nanotube nanocomposite (NiO/MWCNTs) and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) in the carbon paste matrix as high sensitive sensors for voltammetric determination of vitamin C have been reported. The oxidation peak potential of vitamin C at the surface of the ([Bmim]BF4) NiO/MWCNT carbon paste electrode (NiO/MWCNTs/([Bmim]BF4/CPE) appeared at 440mV, which was about 200mV lower than the oxidation peak potential at the surface of the simple carbon paste electrode under a similar condition. Also, the oxidation peak current was increased for about 3.7 times at the surface of NiO/MWCNTs/([Bmim]BF4/CPE compared to carbon paste electrode. At an optimum condition (pH7.0), the two peaks are separated ca. 0.44 and 0.85V for vitamin C and vitamin B9. This point shows that vitamin C can be determined in the presence of vitamin B9. The linear response range and detection limit were found to be 0.1–1000μM and 0.06μM, respectively. The proposed sensor was successfully applied for the determination of vitamin C in food and drug samples.

A highly sensitive NADH biosensor using nitrogen doped graphene modified electrodes

The present work describes the fabrication of highly sensitive and selective β-nicotinamide adenine dinucleotide (NADH) sensor using nitrogen doped graphene (NDG). NDG modified glassy carbon electrode (GCE) exhibits strong and stable electrocatalytic response towards NADH oxidation. A substantial (253mV) decrease in the overpotential for NADH oxidation reaction (compared to GCE) is observed at NDG/GCE. NDG was prepared using hydrothermal procedure and characterized using spectroscopy and microscopy techniques. Furthermore, amperometric responses of NDG/GCE have high sensitivity towards NADH oxidation at lower oxidation potential and minimization of surface contamination. The fabricated NADH biosensor exhibited enhanced and reproducible sensitivity of 0.16μA/μM (S/N=3) with a response time of <3s and the calculated limit of detection is 0.37μM. A linear dynamic range from 0.5–12μM was observed for the fabricated biosensor with a correlation coefficient (R2) of 0.99. Moreover, the biosensor exhibited strong stability after prolonged usage. The oxidation peak potential at the NDG/GCE remained unchanged even after 15days, with minimum surface contamination. Therefore, NDG materials are found useful and promising candidates for NADH detection and are attractive for dehydrogenase based biosensor.

Simultaneous determination of ascorbic acid, acetaminophen and codeine based on multi-walled carbon nanotubes modified with magnetic nanoparticles paste electrode

Based on incorporating ZnCrFeO4 into multi-walled carbon nanotubes paste matrix (MWCNTs/ZnCrFeO4/CPE), a chemically modified electrode was prepared for the simultaneous determination of ascorbic acid (AA), acetaminophen (AC) and codeine (CO). The prepared electrode, MWCNTs/ZnCrFeO4/CPE, was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The MWCNTs/ZnCrFeO4/CPE showed an efficient electrocatalytic activity for the oxidation of AA, AC, and CO. The separations of the oxidation peak potentials for AA–AC and AC–CO were about 250mV and 630mV, respectively. The calibration curves obtained for AA, AC, and CO were in the ranges of 0.4–730.0μmolL−1, 0.1–368.0μmolL−1, and 0.3–250.0μmolL−1, respectively. The detection limits (S/N=3) were 0.03μmolL−1, 0.009μmolL−1, and 0.01μmolL−1 for AA, AC, and CO, respectively. The method was also successfully employed as a selective, simple, and precise method to determinate AA, AC, and CO in pharmaceutical and biological samples.

Graphene nanoplatelets like structures formed on ionic liquid modified carbon-ceramic electrode: As a sensing platform for simultaneous determination of dopamine and acetaminophen

Room temperature ionic liquid as 1-allyl-3-methylimidazolium tetraflouroborate ([AMIM][BF4]) was used for surface modification of carbon-ceramic electrode. The surface of the modified electrode was characterized using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM) and Raman spectroscopy. Based on these studies we were concluded that deposition of ionic liquid on the carbon-ceramic electrode surface caused the formation of graphene nanoplatelets like structures on its surface.This modified electrode was used for simultaneous electrochemical determination of dopamine (DA) and acetaminophen (AP). Because of effective separation of oxidation peak potentials of DA and AP on modified electrode, simultaneous determination of them was possible. Operational parameters such as amount of IL volume, solution pH, scan rate; which affected the analytical performance of modified electrode were optimized. The calibration curves for DA and AP were linear in the range of 0.1–20μM and 0.1–20μM with the detection limit (S/N=3) of 68nM and 63nM, respectively. The high repeatability, reproducibility, and long-term life time were of modified electrode figure of merits. The present electrode was successfully applied for the determination of DA and AP in some commercial pharmaceutical samples, human blood serum, and urine samples with satisfactory results.

Maternal KIR-B haplotype in combination with fetal HLA-C2 is associated with pregnancy acute atherosis in the decidua basalis

Room temperature ionic liquid as 1-allyl-3-methylimidazolium tetraflouroborate ([AMIM][BF4]) was used for surface modification of carbon-ceramic electrode. The surface of the modified electrode was characterized using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM) and Raman spectroscopy. Based on these studies we were concluded that deposition of ionic liquid on the carbon-ceramic electrode surface caused the formation of graphene nanoplatelets like structures on its surface.This modified electrode was used for simultaneous electrochemical determination of dopamine (DA) and acetaminophen (AP). Because of effective separation of oxidation peak potentials of DA and AP on modified electrode, simultaneous determination of them was possible. Operational parameters such as amount of IL volume, solution pH, scan rate; which affected the analytical performance of modified electrode were optimized. The calibration curves for DA and AP were linear in the range of 0.1–20 μM and 0.1–20 μM with the detection limit (S/N = 3) of 68 nM and 63 nM, respectively. The high repeatability, reproducibility, and long-term life time were of modified electrode figure of merits. The present electrode was successfully applied for the determination of DA and AP in some commercial pharmaceutical samples, human blood serum, and urine samples with satisfactory results.

Application of L-DOPA modified carbon nanotubes as a bifunctional electrocatalyst for simultaneous determination of ascorbic acid, adrenaline, acetaminophen and tyrosine

L-DOPA multi-wall carbon nanotube modified glassy carbon electrode (DOPA-MWCNT-GCE) was used as a bifunctional electrocatalyst for simultaneous quantitative determination of ascorbic acid (AA) and adrenaline (AD). Electrochemical experiments show that the modified electrode plays the role of an excellent bifunctional electrocatalyst for the oxidation of AA and AD in two different potentials. The kinetic parameters such as the electron transfer coefficient, α, and the heterogeneous electron transfer rate constant, k′, for the electrocatalytic oxidation of AA and AD at the DOPA-MWCNT-GCE surface were estimated. Through a different pulse voltammetric (DPV) method, the plot of the electrocatalytic current versus AA and AD concentrations emerged to be constituted of two linear segments with different sensitivities. In addition, detection limits of 1.5μM for AA and 0.62μM for AD were obtained. In DPV, the proposed bifunctional electrocatalyst could separate the oxidation peak potentials of AA, AD, acetaminophen (AC) and tyrosine (Tyr) present in a mixture though, at the bare GCE, the peak potentials overlap. Finally, DOPA-MWCNT-GCE was satisfactorily used for the determination of AA, AD, AC and Tyr in pharmaceutical preparations.

Voltammetric resolution of catechol and hydroquinone at eosin Y film modified carbon paste electrode

A sensitive, selective and reproducible electrochemical method was developed for the electroanalysis of catechol (CC) and hydroquinone (HQ) using eosin Y film modified carbon paste electrode (eosin Y/CPE). The modified electrode lowers the over potential and favours the oxidation of CC and HQ. The effect of scan rate and concentration studies reveals that the electrode process is controlled by the adsorption of an analytes. The simultaneous separation of CC and HQ was achieved in a binary mixture by cyclic voltammetric (CV) and differential pulse voltammetric (DPV) techniques. The separation of the oxidation peak potentials for CC–HQ was about 0.114V and 0.118V by CV and DPV techniques respectively. This peak differences were large enough to determine CC and HQ individually or simultaneously. The lower limit of detection of CC was 0.27μM and 0.79μM for HQ. The eosin Y/CPE was achieved the voltammetric separation of the dihydroxy benzene isomers in a binary mixture by CV technique; this work provides a simple and easy approach for the modification of the bare carbon paste electrode.

Selective electrochemical determination of glutathione from the leakage of intracellular GSH contents in HeLa cells following doxorubicin-induced cell apoptosis

A highly selective method for the electrochemical detection of reduced glutathione (GSH) has been developed on the basis of the product of a reaction between GSH and catechol as the electron mediator on single-walled carbon nanotubes modified glassy carbon electrode. A polymerization-adduct ECE mechanism at SWNTs/GCE was proposed. The oxidation peak potential was −0.160V (vs. Ag/AgCl, sat. KCl) and the oxidation peak current showed a dependence relationship with GSH concentration in the range of 1.0 ∼500.0μM with a detection limit of 0.5μM GSH. The developed method can discriminate GSH from other thiol species such as L-cysteine (Cys) and cysteamine hydrochloride (Cym) within their certain concentration ranges. The as-established electrochemical method has been successfully applied for the determination of GSH from the leakage of intracellular GSH contents in HeLa cells following doxorubicin-induced cell apoptosis.

Influence of Nanostructured Carbon Supports on Nanocatalysts Towards Electrooxidation of Formic Acid for Direct Formic Acid Fuel Cells

Direct formic acid fuel cells (DFAFCs) have been reported as a prominent source of alternative green energy and solution to imminent energy crisis for the last two decades. The challenge to commercialize DFAFCs is mainly the utilization of cost effective, high performance and durable anodic catalyst for electrooxidation of formic acid (HCOOH). Low metal loading, high surface area, good electrical conductivity, excellent stability in acidic and alkaline media, and easy availability make nanostructured carbon supports attractive for fuel cell applications. We report here the comparative studies of three different carbon based support materials and their influence on catalytic activities towards the electrochemical oxidation of HCOOH using mono (20 wt% Pd) and ternary (10 wt% Pd-Ni-Co) composite nano-catalysts with commercial 20 wt% Pd/C (activated carbon, ~500 m2g-1). The nano-catalysts were synthesized using Pd2+, Ni2+ and Co2+ precursors using Vulcan-XC72 (250 m2g-1, <50 nm), Ketjen Black (1400 m2g-1) and graphite nano-particles (GNP) (~10 nm) support materials and NaBH4 as reducing agent. The electrochemical oxidation of HCOOH was conducted at a glassy carbon disk electrode (GCE, 3 mm diameter) pre-casted with 9 µL of each catalyst ink covered with 3 µL Nafion® polymer (5 wt%) in 0.50 M HCOOH-0.10 M H2SO4. The catalytic oxidation behavior of HCOOH of all the catalysts was compared using cyclic voltammetry. Multi-potential step chronoamperometry (CA) was utilized for stability tests. The catalytic behavior of all the ternary nano-catalysts is believed to be ascribed to the direct oxidation pathway of HCOOH as indicated by the oxidation peak potential of ~ -0.2 V vs Hg/Hg2SO4 (satd. K2SO4) reference electrode. In contrast, the synthesized mono catalysts and commercial Pd/C showed both direct and indirect oxidation pathways. The use of Ni and Co also showed synergistic effect as the HCOOH oxidation peak potential was shifted negatively by ~200 mV with respect to that of the commercial catalyst containing even doubled amounts of Pd. Furthermore, CA data showed that GNP and Ketjen Black supported catalysts were almost as stable as the commercial Pd/C, although the electrooxidation current at the Vulcan-XC72 based catalysts decreased by ~50% within about 20 min. On the other hand, Vulcan-XC72 supported catalysts showed the highest HCOOH oxidation current and the rest were in close proximity to one another. Finally, morphology and elemental analyses employing scanning electron microscope and energy dispersive X-ray spectroscopy revealed the different catalytic activity on various support materials were concordant with the electrochemical data as the turbostratic substrates contributed better metal dispersion and uniform size distribution. Financial support from the CAREER Award (CHE-0955878) is gratefully acknowledged.