Carbon Ceramic Electrode Research Articles

Recent Advances with Sulfonated Silica Ceramic Carbon Electrodes for Fuel Cells

Sulfonated silica-based ceramic carbon electrodes (SS-CCE) are prepared using low-cost organosilane precursors that are mixed with the carbon-supported platinum (Pt/C) catalyst in monomer form, and subsequently polymerized and coated onto a gas diffusion layer in a single step. Our lab has demonstrated that that SS-CCEs can achieve similar H2/O2 fuel cell performance as conventional Nafion-based electrodes [1, 2]. Furthermore, these electrode structures display excellent tolerance to dry operating conditions, due to the proton conductivity of the sulfonic acid moiety and the hygroscopic nature of the SiO2 backbone. This is a major advantage over conventional Nafion-based fuel cell electrodes which require the use of heavily humidified gas feeds and are limited to temperature below 80 °C. Therefore SS-CCEs have great potential to improve PEMFC efficiency by reducing parasitic power losses required for gas humidification. Furthermore, they have the potential to reduce the required catalyst loading and extend the operating temperature range of PEMFCs. While these results have been promising, there are few detailed studies of SS-CCE structure-property. Likewise, their durability in operating fuel cells have yet to be proven. In this presentation, we will give an overview of our group’s recent progress towards optimization the synthesis and structure of SS-CCEs. In particular, we have found hydrothermal conditions to be a promising way to enhance performance, promoting a more homogenous distribution of silicate ionomer and more effective bonding to the carbon surface [3]. Likewise, accelerated stress tests indicate that the silicate ionomer also serves to stability the Pt catalysts and enhance its durability [4]. This, along with their tolerance to high temperatures/low relative humidity conditions leads to improved stability of SS-CCE-based fuel cell systems.

Recent Advances with Sulfonated Silica Ceramic Carbon Electrodes for Fuel Cells

Sulfonated silica-based ceramic carbon electrodes (SS-CCE) are prepared using low-cost organosilane precursors that are mixed with the carbon-supported platinum (Pt/C) catalyst in monomer form, and subsequently polymerized and coated onto a gas diffusion layer in a single step. Our lab has demonstrated that that SS-CCEs can perform very well in a fuel cell dry operating conditions, due to the proton conductivity of the sulfonic acid moiety and the hygroscopic nature of the SiO2 backbone. While these results have been promising, there are few detailed studies of SS-CCE structure-property. Likewise, their durability in operating fuel cells have yet to be proven. This paper describes our group’s recent progress towards optimization the synthesis and structure of SS-CCEs in order to enhance performance and promote a more homogenous distribution of silicate ionomer. The durability of SS-CCEs is also compared to that of conventional Nafion-based electrodes.

Nonenzymatic amperometric dopamine sensor based on a carbon ceramic electrode of type SiO2/C modified with Co3O4 nanoparticles

An amperometric nonenzymatic dopamine sensor has been developed. Cobalt oxide (Co3O4) nanoparticles were uniformly dispersed inside mesoporous SiO2/C. A sol-gel process was used for the preparation of this mesoporous composite material (SiO2/C). This mesoporous composite has a pore size of around 13-14nm, a large surface area (SBET 421 m2·g-1) and large porevolume (0.98cm3·g-1) as determined by the BET technique. The material compactness was confirmed by SEM images which showing that there is no phase segregation at the magnification applied. The chemical homogeneity of the materials was confirmed by EDX mapping. The SiO2/C/Co3O4 nanomaterial was pressed in desk format to fabricate a working electrode for nonenzymatic amperometric sensing of dopamine at a pH value of 7.0 and at a typical working potential of 0.25V vs SCE. The detection limit, linear response range and sensitivity are 0.018μmolL-1, 10-240μmolL-1, and 80μA·μmolL-1cm-2, respectively. The response timé of theelectrode is less than 1s in the presence of 60μmolL-1 of dopamine. The sensor showed chemically stability, high sensitivity and is not interfered by other electroactive molecules present in blood. The repeatability of this sensor was evaluated as 1.9% (RSD; for n = 10 at a 40μmolL-1dopamine level. Graphical abstract Schematic presentation of the preparation of a nanostructured composite of type SiO2/C/Co3O4 for electrooxidative sensing of dopamine.

Electrosynthesized Reduced Graphene Oxide-Supported Platinum, Platinum-Copper and Platinum-Nickel Nanoparticles on Carbon-Ceramic Electrode for Electrocatalytic Oxidation of Ethanol in Acidic Media

In this work, the electrocatalytic oxidation of ethanol was studied in acidic media at the wholly electrosynthesized nanocomposites: platinum and its alloys (copper and nickel) anoparticles/reduced graphene oxide on the carbon-ceramic electrode (Pt/rGO/CCE, Pt-Cu/rGO/CCE, and Pt-Ni/rGO/CCE electrocatalysts). The electrosynthesized nanocomposites were characterized by scanning electron microscopy, X-ray powder diffraction, and energy-dispersive X-ray spectroscopy. Electrocatalytic activities of the Pt/rGO/CCE, Pt-Cu/rGO/CCE and Pt-Ni/rGO/CCE toward ethanol oxidation were investigated via cyclic voltammetric and chronoamperometric techniques in 0.1 M H2SO4 solution containing 0.3 M ethanol. The obtained results show that the Pt-Ni/rGO/CCE was catalytically more active and exhibits better electrocatalytic performance toward ethanol oxidation (ECSA=25.28, Jpf=0.156 mA/cm2, Jpf/Jpb=1.12 and Eonset=0.2 V) than Pt-Cu/rGO/CCE (ECSA=19.09, Jpf=0.108 mA/cm2, Jpf/Jpb=0.99 and Eonset=0.3 V) and Pt/rGO/CCE (ECSA=28.28, Jpf=0.092 mA/cm2, Jpf/Jpb=0.55 and Eonset=0.35 V). The result of some effective and important investigational factors was studied and optimize conditions were suggested. Based on the obtained data one can be expected that the studied systems are promising systems for ethanol fuel cell applications.

Enhanced degradation of reactive dyes using a novel carbon ceramic electrode based on copper nanoparticles and multiwall carbon nanotubes

Abstract A novel carbon ceramic electrode consisting of CuNPs and MWCNT was developed to treat reactive orange 84 (RO84) wastewater using ultrasound-assisted electrochemical degradation. The proposed electrode generated more hydroxyl radicals than non-nanoparticle electrodes did. In addition, a new electrochemical sensor was applied to determine residue RO84 in an aqueous medium during discoloration. This sensor is based on a glassy carbon electrode modified with gold nanourchins and graphene oxide and can detect RO84 concentration in the range of 1.0–1200 μmol·L−1 with the detection limit of 0.03 μmol·L−1. The degradation effects of the modified electrode on RO84 were evaluated systematically with different initial pH values, time durations, and amounts of CuNPs and MWCNT. The results suggested that the removal efficiency of RO84 was approximately 83% after 120 min of electrolysis in a phosphate buffer with pH 8.0 using a carbon ceramic electrode made with 4.0 wt% CuNPs and 4.0 wt% MWCNT. The possible mechanism of RO84 degradation was monitored by gas chromatography–mass spectrometry, and degradation pathways were proposed.

Sensitive detection of trace amounts of copper by a dopamine modified carbon ceramic electrode

In this paper, a novel & highly sensitive copper sensor based on a dopamine modified carbon ceramic electrode (CCE) is presented. By immersing the CCE in aqueous solution of dopamine (0.2 M), after a short period of time, a thin film of dopamine was rapidly formed on the surface of the electrode due to its strong adsorption properties. The prepared modified carbon ceramic electrode was characterized by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). Then, the effective parameters on sensor response were optimized and anodic stripping voltammetry (ASV) was used for quantitative determination of copper. The calibration plot was linear over the copper concentration range of 0.1–250 µg L−1. The limit of detection (LOD) was found 0.03 µg L−1 of Cu(II), and for seven successive determinations of 10 and 140 µg L−1 Cu(II), the relative standard deviations were obtained 1.5% and 1.1%, respectively.The dopamine modified carbon ceramic electrode (CCE/DOP), prepared in this study, showed high selectivity and sensitivity via formation of a Cu-dopamine complex and applied for the determination of Cu(II) in real samples with good results.

Silica/Titania Graphite Composite Modified with Chitosan and Tyrosinase Employed as a Sensitive Biosensor for Phenolic Compounds

A mesoporous, high surface area and conductive silica/titania graphite composite modified with chitosan and functionalized with tyrosinase was prepared. The composite was obtained by the sol-gel method and the surface of the resultant material was modified with chitosan solutions containing 5, 10 and 15% by mass. The textural characterization showed that even after modification with chitosan, the composite maintains a pore volume near 0.70 cm3 g-1 and pore diameter between 10 and 50 nm, adequate for enzyme immobilization. The tyrosinase was immobilized on the composite that was modified with 5% chitosan solution. A carbon ceramic electrode was manufactured with this material and was used as an electrochemical biosensor for phenolic compounds, showing low detection limits in the linear range from 40 to 350 µmol L-1 and good sensitivity of 0.284, 0.141 and 0.165 µA µmol-1 L for catechol, dopamine and pyrogallol, respectively. In this composite the enzyme showed to be operative and stable after several months.

Assessment of the Stability of a Mercury Film on a Glass–Ceramic Carbon Electrode when Determining Zinc in the Presence of Manganese by Anodic Stripping Voltammetry

The possibility of assessing the stability of operation of a mercury film graphite electrode in anodic stripping voltammetry using Shewhart control charts (CCs) is shown. The offered technique allows significantly increasing the efficiency of the voltammetric determination of zinc and manganese and taking measurements of analytes in samples during a working day without replacing the mercury film on the electrode surface.

Defective mesoporous carbon ceramic electrode modified graphene quantum dots as a novel surface-renewable electrode: The application to determination of zolpidem

A novel sensitive electrochemical sensor was developed for detection and determination of zolpidem (Zlp) based on graphene quantum dots modified defective mesoporous carbon ceramic electrode (DMCCE-GQDs). The cyclic voltammetry (CV), choronoamperometry (CA), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques were used for electrochemical studies and drug determination. The electrocatalytic currents increased with the Zlp concentration and exhibit two linear dynamic ranges with a detection limit of 0.061μM Zlp (S/N=3). The linear calibration ranges were obtained between 0.1 and 1 and 1–10μM Zlp using the DPV method. The diffusion coefficient (D=4.2×10−5cm2s−1) and the heterogeneous rate constant, (k=7.53×102cms−1) for Zlp were determined. Finally, the modified electrode was successfully applied to determination of Zlp in tablet dosage forms with a mean recovery of 97.6%.

Green synthesized silver nanoparticles @ zeolite type A hybridized with carbon ceramic, AgZA-CCE, as a new nano-electrocatalyst for detection of ultra-trace amounts of rutin

In this study, Ag nanoparticles were green synthesized and a novel nano Ag doped zeolite A modified carbon ceramic electrode (AgZA-CCE) was fabricated. It was applied for the determination of rutin with high sensitivity. A substantial (550 mV) decrease in the overvoltage of rutin oxidation reaction was observed using the AgZA-CCE. The calibration graph was linear over the concentration range of 0.005–0.21 µM and the detection limit was estimated 0.47 nM. The resulted diffusion coefficient was equal to 4.22 × 10−7 cm2 s−1. The proposed electrode was used for the determination of rutin in real samples with satisfactory results.

Ionic liquid/single‐walled carbon nanotubes composite film modified carbon‐ceramic electrode as an electrochemical sensor for the simultaneous determination of epinephrine and uric acid

In the present work, a carbon–ceramic electrode (CCE) modified by a composite of an ionic liquid and single-walled carbon nanotubes (IL-SWCNT/CCE) was prepared for the electrochemical determination of epinephrine (EP) in the presence of uric acid (UA). The morphology and surface characteristics of the prepared modified CCE were studied using scanning electron microscopy (SEM). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used for electrochemical studies and determinations. Their results showed that the IL-SWCNT/CCE has high electrocatalytic activity toward the oxidation of EP. The electrochemical behavior of EP is closely dependent on the pH; in basic media, its oxidation process is irreversible and there is no cathodic peak in reverse scan, while in acidic media the electrochemical behavior of EP becomes reversible. DPV measurements showed that the oxidation peak current was linear in the concentration range 1.0 × 10−7 to 2.0 × 10−4 M, and the detection limit was 2.8 × 10−8 M. Also, it was confirmed that the IL-SWCNT/CCE can be used for the simultaneous measurement of EP and UA. The obtained results indicate that the IL-SWCNT/CCE has high stability, reproducibility, and repeatability. Finally, the developed electro-analytical method was successfully applied for the determination of EP in human serum and urine samples without any interference.

A graphene oxide modified carbon ceramic electrode for voltammetric determination of gallic acid

In this paper, a new type of carbon ceramic electrode modified with reduced graphene oxide (RGO) was fabricated via sol-gel method. The constructed electrode was used in square wave voltammetric (SWV) determination of gallic acid (GA). The electrochemical properties of the fabricated electrode and voltammetric behavior of gallic acid were investigated by cyclic voltammetry (CV). The SWV investigation of GA was performed in Britton-Robinson buffer at pH 2 as a supporting electrolyte. Under the optimized SWV mode parameters, the oxidation peak current (best measured at 0.57 V vs Ag/AgCl) increased linearly in the wide concentration range from 0.51 to 46.40 μmol L−1. The calculated values of LOD and LOQ were 0.0867 and 0.263 μmol L−1, respectively. The presented results were obtained without any preconcentration procedure. During the experiment, the effect of common interfering molecules was also investigated. Finally, the usability of the proposed method was verified by the quantitative analysis of GA in red wine, black tea and white tea samples.

Enhancing fuel cell catalyst layer stability using a dual-function sulfonated silica-based ionomer

Sulfonated-silica ceramic carbon electrodes (SS-CCE) were prepared by an in-situ sol-gel reaction where tetraethylorthosilicate and 3-trihydroxysilyl-1-propanesulfonic acid (TPS) are polymerized in the presence of a commercial Pt/C catalyst. The resultant catalyst layer is a promising candidate for application in proton exchange membrane fuel cells (PEMFCs), however their durability is unproven to date. To that end, we have examined the durability of these SS-CCE’s in fuel cells. The SS-CCE was subjected to an accelerated stress testing (AST) and its fuel cell performance was assessed before and after the AST. Remarkably, the SS-CCE was substantially more durable than a conventional Nafion-based electrode employing the identical Pt/C catalyst. Detailed electrochemical tests and post-mortem analysis of each electrode revealed in addition to its primary function of conducting ions/retaining water, the sulfonated silica ionomer takes on the dual role of stabilizing the Pt/C catalysts through an electronic effect that mitigates Pt nanoparticles Ostwald ripening/agglomeration. The method for producing SS-CCE is highly versatile and could potentially be employed with any fuel cell catalyst. It is therefore proposed that this dual-function ionomer could be paired with almost any Pt/C (or supported alloy catalyst) and extend the operational lifetime of fuel cells without comprising beginning of life performance.

Preparation and characterization of a carbon nanotube-based ceramic electrode and its potential application at detecting sulfonamide drugs

In this work, we report the construction, characterization, and the potential application of carbon-ceramic electrodes prepared with functionalized multi-walled carbon nanotubes (CCE/f-MWCNT) to detect two sulfonamide drugs: sodium sulfacetamide (SFC) and sulfadiazine (SFD). Prior to the construction of CCE/f-MWCNT, MWCNT samples were functionalized by using an acid treatment (HNO3/HClO4), and then characterized by FTIR spectroscopy, XRD, FESEM, and Raman spectroscopy. These techniques were also employed to characterize the prepared carbon-ceramic electrodes, and the obtained results demonstrated that the MWCNT were properly dispersed in the silica matrix. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy experiments showed that the f-MWCNT could enhance the electrochemical performance of the electrodes, as a consequence of its high electrical conductivity and large surface area. The antibacterial drugs were determined with CCE/f-MWCNT by employing CV and differential pulse voltammetry (DPV). A linear relationship between DPV peak currents and SFC and SFD concentrations was verified separately in the range from 9.9 to 177.0 µmol L− 1 in 0.04 mol L− 1 BR buffer solution pH 6.0. Detection and quantification limits were found to be 1.06 and 3.54 µmol L− 1 for SFC and 2.31 and 7.71 µmol L− 1 for SFD, respectively. Besides the good sensitivity, the CCE/f-MWCNT showed reproducibility and specificity, since its response was not significantly affected by the presence of electroactive interfering compounds. The promising analytical performance of the CCE/f-MWCNT was confirmed by determining SFC and SFD in commercial veterinary formulations, with percent recoveries ranging from 99.9 to 101.1% for SFC and from 99.8 to 102.2% for SFD.

Lead-doped carbon ceramic electrode as a renewable surface composite electrode for the preparation of lead dioxide film and detection of l-tyrosine

Lead-doped carbon ceramic electrode as a new type of renewable composite electrode was prepared by mixing the lead powder with electrode matrix before gelation. Pb on the electrode surface was then converted to lead dioxide by the potential scanning of the composite electrode in 0.1 M NaOH solution in the range of − 0.3 to 0.7 V versus SCE. The composition and morphology of the electrodes were studied by energy dispersive X-ray spectrometry, scanning electron microscopy, and atomic force microscopy techniques. Cyclic voltammetry and chronoamperometry techniques were also used to study the electrocatalytic activity of the modified electrode toward the oxidation of the l-tyrosine. The best results were obtained at a working potential of 0.45 V (vs. SCE) in 0.1 M NaOH solution. The sensor exhibited a good linear response in the range of 5–1458 µM with a coefficient of determination of 0.9963. The detection limit was 0.77 µM, and sensitivity was 37.4 μA mM−1. In addition, the modified electrode showed high stability and interference-free response for to detection of the l-tyrosine.

Preparation of Nanocomposite Modified Defective Mesoporous Carbon (DMC) Ceramic Electrode (DMCCE): Application to Electrochemical Determination of Clonazepam

Preparation of Nanocomposite Modified Defective Mesoporous Carbon (DMC) Ceramic Electrode (DMCCE): Application to Electrochemical Determination of Clonazepam

Carbon ceramic electrodes modified with mixed oxides SiO2/SnO2 for determination of levofloxacin

The preparation of a carbon ceramic electrode modified with SnO2 (CCE/SnO2) using tin dibutyl diacetate as precursor was optimized by a 23 factorial design. The factors analyzed were catalyst (HCl), graphite/organic precursor ratio, and inorganic precursor (dibutyltin diacetate). The statistical treatment of the data showed that only the second-order interaction effect, catalyst × inorganic precursor, was significant at 95% confidence level, for the electrochemical response of the system. The obtained material was characterized by scanning electron microscopy (MEV), X-ray diffraction (XRD), RAMAN spectroscopy, XPS spectra, and voltammetric techniques. From the XPS spectra, it was confirmed the formation of the Si–O–Sn bond by the shift in the binding energy values referred to Sn 3d3/2 due to the interaction of Sn with SiOH species. The incorporation of SnO2 provided an increment of the electrode response for levofloxacin, with Ipa = 147.0 μA for the ECC and Ipa = 228.8 μA for ECC/SnO2, indicating that SnO2 when incorporated into the silica network enhances the electron transfer process. Under the optimized working conditions, the peak current increased linearly with the levofloxacin concentration in the range from 6.21×10−5 to 6.97×10−4 mol L−1 with quantification and detection limits of 3.80×10−5 mol L−1 (14.07 mg L−1) and 1.13×10−5 mol L−1 (4.18 mg L−1), respectively.

A non-enzymatic glucose sensor based on CuO-nanostructure modified carbon ceramic electrode

Mesoporous silica-graphite composite (SiO2/C-graphite) was synthesized by the sol-gel technique. The surface area (SBET=98.93m2/g), pore volume (0.30cm3/g) and pore size (12.16nm) were characterized by BET. The novelty of this work lays in the fabrication of material in which ceramic material (SiO2/C-graphite) was decorated with copper oxide (CuO) nanostructure. SEM images revealed material compactness without phase segregation and EDX mapping showed a homogenous structure. Pressed disk electrode fabricated with SiO2/C/CuO nanocomposite material was evaluated as an amperometric non-enzymatic glucose sensor in 0.1M NaOH solution. The linear response range, sensitivity, detection limit, and quantification limit were 0.02–20.0mmolL−1, 0.06μmolL−1, 472μA mmol−1L−1cm−2, and 0.76mmolL−1, respectively. The electrode response time is <1s with the addition of 0.02mmolL−1 glucose. The electrode is chemically stable, exhibits rapid and excellent sensitivity and does not show any interference from coexisting species present in the blood samples. The proposed sensor repeatability was assessed as 1.9% RSD for ten measurements of 13.0mmolL−1 glucose solution. The sensor tested to ascertain glucose in blood serum showed to be a promising tool for the future evolution of non-enzymatic glucose sensors.

A carbon ceramic electrode modified with bismuth oxide nanoparticles for determination of syringic acid by stripping voltammetry

A new type of carbon ceramic electrode modified with bismuth oxide nanoparticles (referred to as Bi-CCE) was fabricated via the sol-gel method. The Bi-CCE was applied to the determination of syringic acid by square wave adsorptive stripping voltammetry. The electrochemical properties of the Bi-CCE and the voltammetric response to syringic acid were investigated by cyclic voltammetry. The effects of the pH value of supporting electrolyte, of accumulation potential, accumulation time, SW mode parameters, and of possible interferents were tested. Under optimized conditions, the oxidation peak current (best measured at 0.8 V vs Ag/AgCl after an accumulation time of 20 s) increases linearly in the 0.4 to 24 μmol·L−1 syringic acid concentration range. Other figures of merit include an LOD of 47 nmol·L−1, a sensitivity of 3.3 μA·μmol−1·L·cm−2, and a relative standard deviation of 4.7% (for n = 5) at 2 μmol·L−1 of syringic acid. The method was successfully applied to the determination of syringic acid in red, white and rose wine as well as water samples.

Developing a highly sensitive electrochemical sensor using thiourea-imprinted polymers based on an MWCNT modified carbon ceramic electrode

In the present study, a new electrochemical sensor based on Molecularly Imprinted Polymer (MIP) was designed for detection and determination of Thiourea (TU) in industrial and biological media. The effect of different parameters, such as solution pH and duration of TU pre-concentration, on the electrode surface was investigated along with optimization of MIP and MWCNT quantities for fabrication of the electrode. The study was conducted using the statistical respond surface methodology. The optimized conditions were determined as MWCNT=3.3mg and MIP=12.3mg for fabrication of the sensor. Also, a pH of 8.0 and a time duration of 26.0min were found for pre-concentration of TU on the prepared sensor. The results showed that the developed sensor (TUMIP/MWCNT/CCE) has a higher sensitivity than bare carbon ceramic electrode (CCE), MWCNT/CCE, and TUMIP/CCE. The sensor showed two linear response ranges of 0.05–5.0nM and 5.0–1100.0nM and a detection limit of 8.0pM versus TU. Finally, the sensor was satisfactorily used to determine TU in the copper refinery electrolyte of Sar-cheshmeh copper Co., and in such real samples as tap water and orange juice.