Journal of the Electrochemical Society

/Journal of the Electrochemical Society

Journal of the Electrochemical Society

Low Noise Field Effect Biosensor with Electrochemically Reduced Graphene Oxide

2018-06-05T16:31:11+00:00 June 5th, 2018|Categories: Publications|Tags: , |

Reduced graphene oxide, in various configurations has been extensively researched as field effect transistor (FET) biosensor, but they usually exhibit low signal to noise ratio. In this paper, we report the fabrication of low noise FET biosensors with electrochemically reduced graphene oxide(ERGO) on fluorine doped tin oxide(FTO) glass, directly by electrochemical reduction of GO in solution. It has been observed that the sensor is capable of detecting down to1 fM concentration of Hep-B in serum with a dynamic range from 1 fM to 20 pM, linearity of around 95% and current sensitivity of 1.21 mA. Moreover, the signal to noise ratio is around 80 in serum, which is enhanced by more than one order of magnitude compared to the most sensitive reports. Further, the presence of Hep-B can be confirmed by the Lorentzian nature of noise spectra, which makes the detection more precise. The combined advantages of low cost and clean fabrication coupled with sensitive and reliable performance renders the device suitable for point of care diagnostics.

Published in: "Journal of the Electrochemical Society".

Cobalt Deposition in Graphene Quantum Dot Bath: Electrochemical and Spectroscopic Features: A Prospective Sensor Material

2018-04-19T00:29:19+00:00 April 19th, 2018|Categories: Publications|Tags: , |

We have demonstrated here that graphene quantum dots (GQD) bind to cobaltous ion giving it a flowery structure. As a result of this binding the cyclic voltammetric peak potential shows a cathodic shift with reference to unbound cobaltous ion. From the electrochemical data, it is estimated that Co2+ is hexa coordinated with GQD to form the bound species. The electrochemical reduction of cobaltous ion is carried out using four baths. A spectrophotometric examination of aquo cobaltic solution shows a characteristic maximum at 508 nm that is absent when cobaltous ion is in GQD bath. Co composite has been galvanostatically deposited on metal substrates. Fourier transform infrared spectroscopy (FTIR) of Co bound GQD shows distinct peaks at 3246(broad) cm–1, 2089 cm–1, 1639 cm–1, 1392 cm–1, 1274 cm–1, 1099 cm–1, 536 cm–1 that can be attributed to Co-C stretching and C-C stretching. The thermogravimetric analysis (TGA) of the composite shows that it is thermally stable from decomposition up to 600°C. The energy dispersion analysis (EDAX) of the deposited Co shows the presence of carbon and cobalt at 0.25 keV and 7.0 eV respectively. The electrochemically deposited graphene composite responds rapidly to a flowing hydrogen gas stream.

Published in: "Journal of the Electrochemical Society".

Eco-Friendly Synthesis of Biocompatible Pectin Stabilized Graphene Nanosheets Hydrogel and Their Application for the Simultaneous Electrochemical Determination of Dopamine and Paracetamol in Real Samples

2018-04-19T00:29:18+00:00 April 19th, 2018|Categories: Publications|Tags: , |

The development of novel and simple active sensing materials is still interested to fabricate a new and improved sensing devices for many industrial, medical and environmental applications. In this work, we have synthesized a new type of pectin (PT) and reduced graphene oxide (RGO) hydrogels (PT/RGO) by using simple sonochemical methods and further used as an active sensing material for simultaneous electrochemical detection of dopamine (DA) and paracetamol (AC). In general, PT and RGO have substantial electrocatalytic activity due to the presence of active functional groups. Herein, the successful formation of PT wrapped RGO was studied by using various analytical techniques. Subsequently, the electrochemical performance of PT/RGO modified glassy carbon electrode (GCE) toward the detection of DA and AC were systematically examined by using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques. As the results, PT/RGO/GCE exhibits the excellent electrochemical activity with a low detection limit (LOD) of 1.5 nM and 1.8 nM, for DA and AC respectively. Especially, the possible mechanism behind the proposed sensor (PT/RGO/GCE) toward detection of DA and AC was clearly scrutinized. In addition, the observed excellent stability, and selectivity of PT/RGO/GCE greater support for the real time detection of DA and AC in human serum and pharmaceutical samples. Thus, the proposed PT/RGO is believed as an exclusive active sensing material with desired properties for future electrochemical sensor applications.

Published in: "Journal of the Electrochemical Society".

The Effect of CNTs on Performance Improvement of rGO Supported Fe-Nx/C Electrocatalysts for the Oxygen Reduction Reaction

2018-04-19T00:29:16+00:00 April 19th, 2018|Categories: Publications|Tags: , |

As a widely investigated category of non-precious metal electrocatalysts for the oxygen reduction reaction (ORR), metal-Nx-C materials are gaining increasing attention both in the rational synthesis of catalysts and in the study of structure-activity relationships. Carbon supports are important to the performance of these catalysts toward the ORR. Graphene has been used in many electrocatalysts due to its notable characteristics, such as large specific surface area, and high conductivity, but it is further limited by the tendency to agglomerate. Here, carbon nanotubes (CNTs) were employed to effectively suppress the agglomeration of graphene. The binary carbon complex was loaded with iron phthalocyanine (FePc), achieving better activity than commercialized Pt/C (30 wt%) with a positive shift of half-wave potential of 20 mV after heat-treatment at 750°C. SEM, TEM, XPS and XAS measurements revealed that the insertion of CNTs not only suppressed the stacking of graphene layers, but also enhanced the catalytic performance during the RRDE and Zn-air battery tests in alkaline electrolyte by exposing more ORR active sites in the Fe-Nx structure.

Published in: "Journal of the Electrochemical Society".

Screen Printed Graphene Oxide Textile Biosensor for Applications in Inexpensive and Wearable Point-of-Exposure Detection of Influenza for At-Risk Populations

2018-04-17T14:28:05+00:00 April 17th, 2018|Categories: Publications|Tags: , |

A textile screen-printed biosensor was developed using silver conductive electrodes and graphene oxide transduction film built upon both nanoporous polyamide and consumer utility textiles for the detection of environmental exposure to influenza A virus. An affinity assay was constructed upon the graphene oxide layer to introduce influenza protein-specific antibodies to the sensor surface. Validation of fabrication reproducibility and stability, as well as affinity assay stability, was conducted using electrochemical impedance spectroscopy. The textile sensor was utilized for the detection of influenza A in biofluid analog buffer. Its linear dynamic range was from 10 ng/mL to 10 μg/mL with a limit of detection of 10 ng/mL, spanning both pre- and post-symptomatic ranges. The sensor can be integrated into common textiles and worn by at-risk populations to detect exposure to the virus before symptoms manifest. If integrated with Internet-of-Things reporting platforms, this sensor could have the ability to predict potential influenza outbreaks before broad symptoms manifest, reducing the physical and economic burden of the disease.

Published in: "Journal of the Electrochemical Society".

An Inkjet Printed Ti3C2-GO Electrode for the Electrochemical Sensing of Hydrogen Peroxide

2018-04-17T14:28:04+00:00 April 17th, 2018|Categories: Publications|Tags: , |

Novel two-dimensional Ti3C2 MXene nanosheets were successfully prepared by etching Al from Ti3AlC2 in LiF/HCl system. In order to further improve the dispersing property and electrical conductivity of Ti3C2 nanosheets, Ti3C2/graphene oxide (Ti3C2-GO) nanocomposites were synthesized and applied for the fabrication of inkjet-printed hydrogen peroxide (H2O2) sensor. The results of electrochemical characterization show that the prepared sensor maintains the biological activity of hemoglobin (Hb) and can be applied to the practical detection. The printed sensors display a dynamic range from 2 μM to 1 mM and a detection limit of 1.95 μM with a high sensitivity and excellent selectivity for H2O2 determination. Therefore, the printable Ti3C2-GO nanocomposites are an excellent sensing platform for electrochemical determination.

Published in: "Journal of the Electrochemical Society".

Electrochemical Hydrogen Permeation Properties of MoS2 and Ni80Cr20 Films Prepared by Magnetron Sputtering on Pure Iron

2018-04-13T16:29:05+00:00 April 13th, 2018|Categories: Publications|Tags: |

Single-layer MoS2 and Ni80Cr20, as well as a double-layer Ni80Cr20/MoS2, films were fabricated on pure iron substrate by magnetron sputtering, and their hydrogen permeation properties were investigated by electrochemical hydrogen permeation experiments. It was found that the single-layer MoS2 or Ni80Cr20 could act as a barrier effectively retarding hydrogen permeation toward the substrate due to their lower diffusion coefficient. Using the overpotential stepping hydrogen permeation test (OSHPT), the lattice diffusion coefficient (DL) of hydrogen in MoS2 and Ni80Cr20 films was determined to be 8.35 x 10–8 and 1.76 x 10–9 cm2/s, respectively. Furthermore, it was observed that the use of Ni80Cr20 as the intermediate layer not only could improve the surface state of MoS2 after hydrogen permeation but also enhanced the effect of retarding hydrogen permeation in the double-layer Ni80Cr20/MoS2 film. In addition, the influences of MoS2 and Ni80Cr20 films on the hydrogen evolution reaction (HER) were also investigated.

Published in: "Journal of the Electrochemical Society".

Core-Shell Nanoparticles/Two-Dimensional (2D) Hexagonal Boron Nitride Nanosheets with Molecularly Imprinted Polymer for Electrochemical Sensing of Cypermethrin

2018-04-12T16:28:14+00:00 April 12th, 2018|Categories: Publications|Tags: , |

Cypermethrin ([RS]-alpha-cyano-3-phenoxybenzyl [1RS, 3RS; 1RS, 3SR]-3-[2,2-dichlorovinyl]-2,2-dimethylcyclopropanecarboxylate) is a crucial pyrethroid and it is generally used as poison against crop pests, domestic insects and ectoparasites in farmed fish. A new molecular imprinted sensor approach based on core-shell type nanoparticles ([email protected]) incorporated two-dimensional (2D) hexagonal boron nitride (2D-hBN) nanosheets was presented for cypermethrin (CYP) detection in wastewater samples. All nanomaterials’ formation and properties were highlighted with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) method, energy dispersive X-ray analysis (EDX), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CYP imprinted voltammetric sensor was improved in presence of 80.0 mM phenol containing 20.0 mM CYP by CV. 1.0 x 10–13 – 1.0 x 10–8 M and 3.0 x 10–14 M were founded as the linearity range and the detection limit (LOD). Finally, CYP imprinted glassy carbon electrode (GCE) was used for wastewater sample analysis in presence of the other competitor agents such as deltamethrin (DEL), tetrametrin (TET) and permethrin (PER). In addition, the prepared sensor was investigated in terms of stability and repeatability.

Published in: "Journal of the Electrochemical Society".

Flexible Electrochromic V2O5 Thin Films with Ultrahigh Coloration Efficiency on Graphene Electrodes

2018-04-11T14:28:21+00:00 April 11th, 2018|Categories: Publications|Tags: |

Flexible multi-color electrochromic V2O5 thin films have been prepared by electrochemical deposition on the double-layer Graphene/PET substrates. The deposited films have a layered structure with nano-crystals in the amorphous matrix, which contributes to an ultrahigh coloration efficiency of ~555.83 cm2 C–[email protected] nm and a large transmittance modulation of 68.94% @800 nm. The large interlayer distance of 1.20 nm, good electrolyte penetration, and short lithium ion diffusion distance make some key electrochromic parameters competitive in our proposed devices. The low-temperature-processed V2O5 thin films on Graphene would provide us an opportunity to design and prepare flexible electrochromic devices.

Published in: "Journal of the Electrochemical Society".

A Dual-Coreactants Electrochemiluminescent Immunosensor for Procalcitonin Detection Based on CdS-MoS2 Nanocomposites

2018-04-11T14:28:19+00:00 April 11th, 2018|Categories: Publications|Tags: |

A novel dual-coreactants electrochemiluminescent (ECL) immunosensor based on CdS-MoS2 nanocomposites was designed for detection of procalcitonin (PCT). The CdS-MoS2 nanocomposites were synthesized through a simple one-pot hydrothermal method, and served as highly efficient luminescent material for the ECL immunosensor. In addition, we used H2O2 and K2S2O8 as dual-coreactants, generating stronger ECL emission than that of K2S2O8 or H2O2 as an individual coreactant, which could improve sensitivity of the immunosensor. Under optimum conditions, the ECL assay for PCT detection was developed with excellent sensitivity of a concentration variation from 0.0001 to 10 ng mL–1 and limit of detection down to 33 fg mL–1(RSD = 0.10). Additionally, the proposed immunosensor showed high specificity, good reproducibility, and long-term stability.

Published in: "Journal of the Electrochemical Society".

Reduced Graphene Oxide Screen-Printed FTO as Highly Sensitive Electrodes for Simultaneous Determination of Dopamine and Uric Acid

2018-04-11T14:28:17+00:00 April 11th, 2018|Categories: Publications|Tags: , |

A novel electrochemical sensor was fabricated by simply screen printing reduced graphene oxide (rGO) paste on F-doped tin oxide (FTO) (rGO-SP-FTO) followed by sintering at 450°C in Argon and employed for detecting dopamine (DA) and uric acid (UA) simultaneously. The rGO film was characterized by using Raman spectroscopy, field emission scanning electron microscope (FE-SEM), and Fourier transform infrared spectroscopy (FTIR). The surface sensing features of rGO-SP-FTO were studied with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The rGO-SP-FTO electrode exhibited foremost sensitivity in simultaneous detection of DA and UA without any interference from ascorbic acid (AA). The rGO-SP-FTO electrode showed a good linear response in the range of 0.5–50.0 μM and 5.0–300 μM with detection limits (S/N = 3) of 0.07 μM and 0.39 μM for DA and UA, respectively. The interactions between screen printed rGO with FTO electrode and their influence on how rGO-SP-FTO electrode interacted with UA, DA, and AA were analyzed from experimental observations. The rGO-SP-FTO electrode was able to detect DA in dopamine hydrochloride injection (DAI) and UA in urine sample effectively. Moreover, the designed electrochemical sensor exhibited excellent stability and reproducibility.

Published in: "Journal of the Electrochemical Society".

Preparation and Electrochemical Properties of (Ru,Ir,Sn)O2 Electrodes Modified with Graphene Barrier

2018-04-11T14:28:16+00:00 April 11th, 2018|Categories: Publications|Tags: , |

To overcome the short lifetime and low electrochemical activity of dimensionally stable anodes, we developed a novel anode material, the (Ru,Ir,Sn)O2/G electrode, for chlorine evolution reaction. The (Ru,Ir,Sn)O2/G electrode was prepared by introducing a graphene layer into the (Ru,Ir,Sn)O2 coating via thermal decomposition. energy-dispersive spectroscopy results revealed that graphene was successfully retained in the (Ru,Ir,Sn)O2 coating. In contrast to the (Ru,Ir,Sn)O2 electrode, the microstructure of the (Ru,Ir,Sn)O2/G electrode was flat, and there were fewer surface cracks. Linear sweep voltammetry showed values of the chlorine and oxygen evolution overpotentials of the prepared (Ru,Ir,Sn)O2/G electrode of 1.076 V and 1.290 V, respectively. This indicates that the electrocatalytic activity of the (Ru,Ir,Sn)O2/G electrode is better than that of the (Ru,Ir,Sn)O2 electrode. Moreover, electrochemical impedance spectroscopy and an accelerated service lifetime experiment were conducted to study the stability of (Ru,Ir,Sn)O2/G electrodes. The results indicate that the resistance of the (Ru,Ir,Sn)O2/G electrode for the oxygen evolution reaction increased and the accelerated lifetime was 3.35 times longer than that of the (Ru,Ir,Sn)O2 electrode at 2 A/cm2 in 0.5 mol/L H2SO4.

Published in: "Journal of the Electrochemical Society".

Transient High-Power Output of Aprotic Li-O2 Batteries Based on Cathode Capacitance Behavior

2018-04-11T14:28:15+00:00 April 11th, 2018|Categories: Publications|Tags: , |

Due to the sluggish oxygen reduction reaction (ORR) process of an O2 cathode, the power delivery of aprotic Li-O2 batteries (A-LOBs) is widely considered to be very poor. However, this work demonstrates the transient high-power output of A-LOBs based on the capacitive feature of the O2 cathode, including the intrinsic capacitance of cathode material and the ORR pseudocapacitance of the absorbed O2 on the cathode surface, by using graphene with high specific surface area. The O2 cathode delivers a high specific power of 12 026 W kggraphene–1 while also providing a large specific energy of 1216 Wh kggraphene–1. Pulse-discharge tests show that A-LOBs can achieve the transient high power output at high current via the “capacitor-type”, while maintaining the high energy output at low current due to the “battery-type” (ORR). This work indicates that A-LOBs can deliver both high energy density and high transient power, which may be an appeal for the next-generation electric vehicles.

Published in: "Journal of the Electrochemical Society".

Preparation of Ultrathin Chiffon-like Ni-Al LDHs/Graphene Composite: Interlayer Stacking of Two-Dimensional Charged Panels via Electrostatic Self-Assembly for Supercapacitor Electrodes

2018-04-11T14:28:13+00:00 April 11th, 2018|Categories: Publications|Tags: , |

In this article, Ni-Al LDHs/graphene composite is successfully fabricated via exfoliation and restacking method. As fabricated composite exhibits ultrathin nature of exfoliated LDHs deposited onto surface of graphene, yielding special chiffon like structure. Such structure can effectively overcome the agglomeration of initial LDHs and graphene sheets. The results of electrochemical performance confirm that Ni-Al LDHs/graphene composite exhibit enhanced performance in comparison with LDHs, which is related to the special chiffon like structure and high conductivity of graphene nanosheets. High performance of as-fabricated material can be identified via various electrochemical tests. In addition, an assembled asymmetric supercapacitor based on Ni-Al LDHs/graphene and active carbon exhibits a maximum energy density of 46.4 Wh kg–1 as well as a maximum power density of 6080 W kg–1, which indicates the potential of composite applied in energy storage-conversion devices.

Published in: "Journal of the Electrochemical Society".

Electrosynthesis of Two-Dimensional TiC and C Materials from Ti3SiC2 in Molten Salt

2018-04-11T14:28:12+00:00 April 11th, 2018|Categories: Publications|Tags: |

The two-dimensional (2-D) multilayer structured TiC and carbide-derived carbon (CDC) have been prepared by electrochemical etching of ternary layered carbide–Ti3SiC2 in molten CaCl2 at 900°C with 2.5 V and 3.0 V, respectively. Ti3SiC2 powder was pressed to form a pellet which was then served as the anode, and a graphite rod was used as the cathode. The obtained TiC product possesses a specific surface area of 653 m2 g–1 and a total pore volume of 0.56 cm3 g–1 with a narrow pore size distribution (average pore diameter of 2.0 nm). The obtained CDC material shows a layer graphene-like nanosheets structure, and amorphous carbon coexists with graphitic carbon ribbon in the product. The Raman analysis confirms that the ID/IG ratio of the CDC nanosheets is 1.17, indicating the lower degree of graphitization. The layered CDC nanosheets possess a specific surface area of 623 m2 g–1 and a total pore volume of 2.06 cm3 g–1 with an average pore diameter of 20–70 nm. It is suggested that the molten salt electrochemical etching process is a novel method for the production of 2-D multilayer material with tuned pores, and have penitential to be used for a variety of applications.

Published in: "Journal of the Electrochemical Society".

The Effect of Graphene on the Deposition and Mechanical Property of Ni-Fe-Graphene Composite Coating

2018-04-11T14:28:10+00:00 April 11th, 2018|Categories: Publications|Tags: , |

Electrodeposited Ni-Fe-Graphene composite coatings have been prepared on the aluminum alloy substrate from alkaline Ni-Fe alloy electrolyte with varied graphene nanoplatelets (GNPs) concentrations from 0.05 g L–1 to 3 g L–1. The effect of graphene concentration on the microstructure, element composition and mechanical property of Ni-Fe-Graphene composite coating has been investigated. The results indicate that the incorporation of GNPs into the coatings promotes the co-deposition of Ni2+ in the electrolyte. Graphene content presents a negative correlation with the iron content in the composites. Graphene content and dispersion in the coatings both play a key role in the properties and when graphene concentration is 1 g L–1, Ni-Fe-Graphene composite coating exhibits the highest hardness (912.6 HV) and best wear resistance (friction coefficient of 0.1990). It is attributed to the grain refinement, excellent mechanical property and self-lubricant of GNPs. The morphology, microstructure and element composition of deposited composites have been characterized using scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), X-ray diffraction (XRD). Raman spectrum is used to characterize the presence of GNPs in the composites.

Published in: "Journal of the Electrochemical Society".

Fast Response, Carbon-Black-Coated, Vertically-Oriented Graphene Electric Double Layer Capacitors

2018-04-11T14:28:08+00:00 April 11th, 2018|Categories: Publications|Tags: , |

Development of electrical double layer capacitors using vertically oriented graphene nanosheets with fast response continues. The inherent open morphology of the nanosheets allows efficient access to charge storage surfaces, making them suitable for AC line filtering. However, since the overall surface area is only about a factor of ~310x over the geometric area, the specific capacitance available remains limited. This work presents utilization of the conventional growth of vertically oriented graphene nanosheets on Ni substrates as the underlying architecture for coating with high surface area carbon black to substantially increase the specific capacitance while retaining the open morphology to allow good frequency response at 120 Hz. The carbon black coating was deposited on ~1.2 μm and ~2.5 μm high nanosheets using an aerosol spray method. Deposition times from 0–8 s, in 1 s intervals, provided coatings which translated into a specific capacitance of 2.3 mF/cm2 at 120 Hz (8 s coating) and a volumetric capacitance of 4.6 F/cc (energy storage elements). Improvements in the uniformity of the carbon black coatings suggest that much higher specific capacitances are possible. COMSOL models of high density VOGN grown to 10 μm high and covered uniformly with 100 nm of carbon black coating suggest a capacitance of ~42 mF/cm2 with acceptable frequency response at 120 Hz can be achieved.

Published in: "Journal of the Electrochemical Society".

Simultaneous Determination of Hydroquinone, Catechol and Resorcinol with High Selectivity Based on Hollow Nitrogen-Doped Mesoporous Carbon Spheres Decorated Graphene

2018-04-11T14:28:06+00:00 April 11th, 2018|Categories: Publications|Tags: |

For the first time, we have synthesized hollow nitrogen-doped mesoporous carbon spheres decorated graphene (NMC-G) and applied it in the simultaneous determination of hydroquinone (HQ) resorcinol (RC) and catechol (CC) in real samples. In the composite of NMC-G, hollow mesoporous carbon spheres possess high surface area and graphene have shown high electro-catalytic activity to many electroactive substances. As a result, the oxidation overpotentials of HQ, RC and CC decreased and the potential separations were 0.38, 0.49 and 0.11 V for CC and RC, RC and HQ, and HQ and CC, respectively. A linear response was obtained from 5 μM to 150 μM for the simultaneous determination of HQ, RC and CC, the linear equation was I – I0 = 0.7695 + 0.08751CHQ for HQ, I – I0 = 0.00858 + 0.02243CRC for RC and I – I0 = 0.5027 + 0.07829CCC for CC, respectively. Furthermore, the concentration of HQ, RC, and CC were assayed in tap water samples, the recoveries were from 95.0% to 106.6%.

Published in: "Journal of the Electrochemical Society".

Graphene/TiO2-Ag Based Composites Used as Sensitive Electrode Materials for Amaranth Electrochemical Detection and Degradation

2018-03-31T23:17:35+00:00 March 31st, 2018|Categories: Publications|Tags: |

Graphene/TiO2-Ag based composites having various quantities of TiO2-Ag nanoparticles (5, 10 or 15 wt%) were successfully prepared through a facile chemical-thermal route. The morphological and structural characteristics of the synthesized materials denoted GTA-5, GTA-10 and GTA-15 were investigated by TEM, XRD and FTIR techniques. The composites were used for the modification of three gold electrodes (Au/GTA-5, Au/GTA-10, Au/GTA-15) which were next employed in the electrochemical detection and degradation of amaranth (an azo dye model). The electrode with the best performance in terms of sensitivity was the Au/GTA-10 electrode. It had considerably larger sensitivity (24 mA/M), in comparison with that of Au/GTA-5 and Au/GTA-15 electrode (8 mA/M and 12 mA/M, respectively). The limit of detection was the same for all modified electrodes (LOD = 1 x 10–7 M; S/N = 3). The Au/GTA-10 electrode was also tested at the electrochemical degradation of amaranth, from aqueous solutions. The degradation reaction followed a first order kinetics with a half-time of degradation of 203 minutes. The response characteristics of the proposed sensor made it a good candidate for integration in the Ubiquitous sensor’s network for IOT.

Published in: "Journal of the Electrochemical Society".

Understanding the Corrosion Resistance of Meso- and Micro-Porous Carbons for Application in PEM Fuel Cells

2018-03-28T14:28:03+00:00 March 28th, 2018|Categories: Publications|Tags: |

The stability of carbon support materials is critical to the lifetime of proton exchange membrane (PEM) fuel cells. Here, we have used a rigorous potential stepping and i/t analysis regime to compare the corrosion resistance of the commonly used microporous carbon black powder, Vulcan carbon (VC), with that of a family of hard-templated mesoporous colloid-imprinted carbon (CICs, with monodisperse pore sizes ranging from 10–50 nm), also using heat-treatment (at 1500°C under N2 for 2 h) to help understand and differentiate their stability. It was found that VC is more corrosion-resistant than the CICs, as VC was already heat-treated at > 1400°C during its preparation, while the CICs experienced a maximum of 900°C during their in-house synthesis. Consistent with this, the CICs have a higher surface density of graphene sheet edges, which are prone to oxidation, and yet these sites are also better at nucleating and stabilizing Pt nanoparticles. Importantly, the smaller the CIC pore size, the better its corrosion resistance, while heat-treatment makes both VC and the CICs more corrosion resistant, giving a 40–60% increase in durability. This is attributed to enhanced hydrophobicity and crystallinity of the carbons and a decrease in the density of defects.

Published in: "Journal of the Electrochemical Society".

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