Displaying publications 81 - 100 of 142 in total

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  1. Application of the central composite design for condition optimization for semi-aerobic landfill leachate treatment using electrochemical oxidation
    Mohajeri S, Aziz HA, Isa MH, Zahed MA, Bashir MJ, Adlan MN
    Water Sci Technol, 2010;61(5):1257-66.
    PMID: 20220248 DOI: 10.2166/wst.2010.018
    In the present study, Electrochemical Oxidation was used to remove COD and color from semi-aerobic landfill leachate collected from Pulau Burung Landfill Site (PBLS), Penang, Malaysia. Experiments were conducted in a batch laboratory-scale system in the presence of NaCl as electrolyte and aluminum electrodes. Central composite design (CCD) under Response surface methodology (RSM) was applied to optimize the electrochemical oxidation process conditions using chemical oxygen demand (COD) and color removals as responses, and the electrolyte concentrations, current density and reaction time as control factors. Analysis of variance (ANOVA) showed good coefficient of determination (R(2)) values of >0.98, thus ensuring satisfactory fitting of the second-order regression model with the experimental data. In un-optimized condition, maximum removals for COD (48.77%) and color (58.21%) were achieved at current density 80 mA/cm(2), electrolyte concentration 3,000 mg/L and reaction time 240 min. While after optimization at current density 75 mA/cm(2), electrolyte concentration 2,000 mg/L and reaction time 218 min a maximum of 49.33 and 59.24% removals were observed for COD and color respectively.
    Matched MeSH terms: Electrolytes/chemistry
  2. Rapid fabrication of oxygen defective α-Fe2O3(110) for enhanced photoelectrochemical activities
    Mohamad Noh MF, Ullah H, Arzaee NA, Ab Halim A, Abdul Rahim MAF, Mohamed NA, et al.
    Dalton Trans, 2020 Sep 14;49(34):12037-12048.
    PMID: 32869793 DOI: 10.1039/d0dt00406e
    Defect engineering is increasingly recognized as a viable strategy for boosting the performance of photoelectrochemical (PEC) water splitting using metal oxide-based photoelectrodes. However, previously developed methods for generating point defects associated with oxygen vacancies are rather time-consuming. Herein, high density oxygen deficient α-Fe2O3 with the dominant (110) crystal plane is developed in a very short timescale of 10 minutes by employing aerosol-assisted chemical vapor deposition and pure nitrogen as a gas carrier. The oxygen-defective film exhibits almost 8 times higher photocurrent density compared to a hematite photoanode with a low concentration of oxygen vacancies which is prepared in purified air. The existence of oxygen vacancies improves light absorption ability, accelerates charge transport in the bulk of films, and promotes charge separation at the electrolyte/semiconductor interface. DFT simulations verify that oxygen-defective hematite has a narrow bandgap, electron-hole trapped centre, and strong adsorption energy of water molecules compared to pristine hematite. This strategy might bring PEC technology another step further towards large-scale fabrication for future commercialization.
    Matched MeSH terms: Electrolytes
  3. Fulltext Polyelectrolytes ability in reducing atrazine concentration in water: surface effects
    Mohd Amin MF, Heijman SG, Lopes SI, Rietveld LC
    ScientificWorldJournal, 2014;2014:162157.
    PMID: 25197693 DOI: 10.1155/2014/162157
    This paper reports on the direct ability of two positively charged organic polyelectrolytes (natural-based and synthetic) to reduce the atrazine concentration in water. The adsorption study was set up using multiple glass vessels with different polymer dosing levels followed by ultrafiltration with a 1 kDa membrane. The addition of polymers exhibited a capability in reducing the atrazine concentration up to a maximum of 60% in surface-to-volume ratio experiments. In the beginning, the theoretical L-type of the isotherm of Giles' classification was expected with an increase in the dosage of the polymer. However, in this study, the conventional type of isotherm was not observed. It was found that the adsorption of the cationic polymer on the negatively charged glass surface was necessary and influential for the removal of atrazine. Surface-to-volume ratio adsorption experiments were performed to elucidate the mechanisms and the polymer configuration. The glass surface area was determined to be a limiting parameter in the adsorption mechanism.
    Matched MeSH terms: Electrolytes/chemistry*
  4. Radiation and temperature effects on conductivity properties of PVA-KOH-PC composite
    Mohd Asri MT, Elias S, Iskandar SM, Abd Halim S, Jumiah H, Zaki AR, et al.
    Med J Malaysia, 2004 May;59 Suppl B:139-40.
    PMID: 15468857
    The aim of this work was to study radiation and the effects of temperature on conductivity properties of polyvinyl alcohol (PVA)-based potassium hydroxide (KOH) and propylene carbonate (PC), where the ionic conduction preferentially occurs in the amorphous phase by free radicals ions through gamma-irradiation. Alkaline composite polymer electrolyte (ACPE) consisting of PVA, KOH and PC of different concentration ratios were prepared by solvent-casting technique. The ACPE were irradiated with different doses from 5 kGy up to 200 kGy. The conductivity properties of the electrolyte films were measured at different frequencies in the range 20 Hz to 1 MHz using LCR meter. The results showed that the conductivity properties were dependent on the radiation dose, temperature and the concentration of the polymer blends.
    Matched MeSH terms: Electrolytes/radiation effects*
  5. Fulltext Conductivity and FTIR studies on PEO-NaCF3SO3 solid polymer electrolyte films
    Mohd Noor Zairi Mohd Sapri, Azizah Hanom Ahmad
    Science Letters, 2016;10(1):11-13.
    MyJurnal
    Solid polymer electrolytes electrolytes based Poly
    (ethylene oxide) (PEO) complexed with sodium
    trifluoromethanesulfonate (NaCF3SO3
    ) salt were prepared by
    using solution cast technique. Ion-polymer ionic conductivity
    and interaction studies have been reported by Electrical
    Impedance spectroscopy (EIS) and Fourier transform infrared
    spectroscopy (FTIR). FTIR studies suggested that there are
    stronger interaction between Na+
    ions and the polymer than
    interaction of anions cations of the salt. The temperature
    dependance electrical conductivity of polymer electrolytes films
    follow Arrhenius relation and the low activation energy 0.2993
    eV was observed for PEO-18 wt. % NaCF3SO3 below 323 K.
    Matched MeSH terms: Electrolytes
  6. Electrochemical behaviour of Ni and Ni-PVC electrodes for the electroxidation of ethanol
    Mohd Syafiq Hamdan, Norazzizi Nordin, Fathrita Mohd Amir, Mohamed Rozali Othman
    Sains Malaysiana, 2011;40:1421-1427.
    In this study, two nickel based electrodes were prepared; nickel foil and nickel-polyvinylchloride (Ni-PVC), in order to study their electrochemical behavior using cyclic voltammetry, CV and chronocoulometry, CC. Ni electrode was prepared from Ni metal foil while Ni-PVC electrode was prepared by mixing a weighed portion of Ni powder and PVC in THF solvent, swirled until the suspension was homogeneous and drying the suspension in an oven at 50oC for 3 h. The dry sample was then placed in a 1 cm diameter stainless steel mould and pressed at 10 ton/cm2. From CV data, Ni-PVC electrode showed a better electrochemical behavior compared to Ni metal foil electrode. The use of Ni-PVC electrode at higher concentration of supporting electrolyte (1.0 M KOH) was better than at lower concentration of the same supporting electrolyte in electroxidation of ethanol. In addition to acetic acid, the oxidation of ethanol also produced ethyl acetate and acetaldehyde.
    Matched MeSH terms: Electrolytes
  7. Fulltext THE POTENTIAL OF SOLID ELECTROLYTE FROM FISH WASTE FOR BATTERY APPLICATION
    Muhammad Ashraff Aiman Roslan, Nik Aziz Nik Ali
    UMT Journal of Undergraduate Research, 2020;2(1):9-14.
    MyJurnal
    This experiment was conducted to study the potential of solid electrolyte from the fish waste of Clarias gariepinus for battery application. The battery was one of the important components that supplies electrical energy to users throughout the world, and it strongly contributed to technology development in the economic sector, transportation, residential as well as agriculture. The presence of ammonia in organic fish waste could produce renewable energy and helped to reduce the use of lithium-ion batteries in modern industries. Two different parameters were being observed in this study, which was the quantity of fish and the number of the cell layer. The process of collecting the fish waste was carried out in the hatchery at Universiti Malaysia Terengganu using two methods, which were filtering and soaking. The result showed that the highest value of energy output was 0.430V from waste filtering of 50 fish and 0.207V from soaking in waste of 50 fish. Meanwhile, the lowest energy output was from the tank that contained ten fish with an energy output of 0.177V for filtering and 0.101V for soaking. Besides, for a different number of the cell layer, the highest value of energy output was 0.414V at 25 layers, and the lowest voltage was 0.175V at five layers. Thus, from the study was observed that the produced voltage was dependent on the quantity of fish and the number of the cell layer, when the quantity of fish and number of cell layer increases, the output energy was also increased.
    Matched MeSH terms: Electrolytes
  8. Fulltext Optical Dielectric Loss as a Novel Approach to Specify the Types of Electron Transition: XRD and UV-vis as a Non-Destructive Techniques for Structural and Optical Characterization of PEO Based Nanocomposites
    Muhammed DS, Brza MA, M Nofal M, B Aziz S, A Hussen S, Abdulwahid RT
    Materials (Basel), 2020 Jul 03;13(13).
    PMID: 32635317 DOI: 10.3390/ma13132979
    The structure and optical properties of polyethylene oxide (PEO) doped with tin titanate (SnTiO3) nano-filler were studied by X-ray diffraction (XRD) and UV-Vis spectroscopy as non-destructive techniques. PEO-based composed polymer electrolytes inserted with SnTiO3 nano-particles (NPs) were synthesized through the solution cast technique. The change from crystalline phase to amorphous phase of the host polymer was established by the lowering of the intensity and broadening of the crystalline peaks. The optical constants of PEO/SnTiO3 nano-composite (NC), such as, refractive index (n), optical absorption coefficient (α), dielectric loss (εi), as well as dielectric constant (εr) were determined for pure PEO and PEO/SnTiO3 NC. From these findings, the value of n of PEO altered from 2.13 to 2.47 upon the addition of 4 wt.% SnTiO3NPs. The value of εr also increased from 4.5 to 6.3, with addition of 4 wt.% SnTiO3. The fundamental optical absorption edge of the PEO shifted toward lower photon energy upon the addition of the SnTiO3 NPs, confirming a decrement in the optical band gap energy of PEO. The band gap shifted from 4.78 eV to 4.612 eV for PEO-doped with 4 wt.% SnTiO3. The nature of electronic transitions in the pure and the composite material were studied on the basis of Tauc's model, while optical εi examination was also carried out to calculate the optical band gap.
    Matched MeSH terms: Electrolytes
  9. The use of inorganic ferrous-ferric oxide nanoparticles to improve fresh and durability properties of foamed concrete
    Mydin MAO, Nawi MNM, Omar R, Khadimallah MA, Ali IM, Deraman R
    Chemosphere, 2023 Mar;317:137661.
    PMID: 36608888 DOI: 10.1016/j.chemosphere.2022.137661
    Efforts to modify cement-based mixtures have continuously engrossed the interest of academics. Favourable impacts of nanoparticles, for instance, fine particle size and great reactivity, have made them be utilized in concrete. Foamed concrete (FC) is immensely porous, and its properties diminish with an increase in the number of pores. To enhance its properties, the FC matrix could be attuned by integrating numerous nanoparticles. The influence of ferrous-ferric oxide nanoparticles (FFO-NP) in FC was not discovered previously in the present body of knowledge. Thus, there is some uncertainty contemplating the mechanism to which extent the FFO-NP can affect the durability properties of FC. Hence, this study focuses on utilizing FFO-NP in the FC matrix. FC specimens with a density of 1000 kg/m3 were cast and tested. The objective was to assess the influence of different FFO-NP weight fractions (0.10%, 0.15%, 0.20%, 0.25%, 0.30%, and 0.35%) on durability properties such as drying shrinkage, porosity, water absorption and ultrasonic wave propagation velocity of FC. The results implied that the presence of a 0.25% weight fraction of FFO-NP in FC facilitates optimal water absorption, porosity, ultrasonic pulse velocity and drying shrinkage of FC. The presence of FFO-NP alters the microstructural of FC from loose needle-like into a dense cohesive microstructure of the cementitious composite. Besides, FFO-NP augments the FC matrix by filling the voids, microcracks, and spaces within the structure. Further than the ideal weight fraction of FFO-NP addition, the accretion of the FFO-NP was found, which caused a decline in durability properties.
    Matched MeSH terms: Electrolytes
  10. Electrodeposited Ge Nanostructures Prepared by Different Non-Aqueous Solutions and their Application in Lithium Ion Battery: A Review
    Nadarajah K, Khan AF, Rahim NA
    Recent Pat Nanotechnol, 2016;10(1):26-43.
    PMID: 27018271
    BACKGROUND: Germanium (Ge) nanostructures exhibit wide range of potential applications in the field of nanoscale devices due to their excellent optical and electrical properties and have gained significant interest due to the Bohr exciton radius. Bohr radius of Ge (24.3 nm) is larger than that of Si (4.9 nm), leading to quantum size effects and nanostructures with controllable bandgaps.

    METHODS: This article provides a comprehensive review on various electrolytes for electrodeposition procedures developed to obtain the Ge nanostructures of desired structure, diameter, and density. We discuss the growth mechanisms and influence of different parameters such as type of solution, concentration, and value of applied potential or current density.

    RESULTS: The ionic liquids can be used for the development of Ge nanostructures and provide extensive electrochemical windows for electrodeposition. The obtained SixGe1-x structures also exhibited strong color change (from red to blue) at room temperature during the electrodeposition, which is likely to be due to a quantum size effect.

    CONCLUSION: The main advantages of the ionic liquids are 'it does not decompose', easy to purify and dry. Moreover, it exhibits fairly extensive electrochemical windows greater than 5 V for electrodeposition. Electrodeposition of SixGe1-x nanostructures from ionic liquids is quite a favorable process. The 3DOM Ge electrode is a promising material for nextgeneration lithium ion battery because of its high irreversible specific capacity. Few relevant patents to the topic have been reviewed and cited.

    Matched MeSH terms: Electrolytes
  11. Fulltext Comparison between Ventriculosubgaleal Shunt and Extraventricular Drainage to Treat Acute Hydrocephalus in Adults
    Nee LS, Harun R, Sellamuthu P, Idris Z
    Asian J Neurosurg, 2017 Oct-Dec;12(4):659-663.
    PMID: 29114279 DOI: 10.4103/ajns.AJNS_122_16
    Context: Hydrocephalus, due to subarachnoid or intraventricular hemorrhage (IVH), meningitis, or tumor compression, is usually transient and may resolve after treatment. There are several temporary methods of cerebrospinal fluid (CSF) diversion, none of it is superior to the other, and the decision is based on its various etiologies and factors. Ventriculosubgaleal shunt (VSGS) is one of those temporary measures, which is a simple and rapid CSF decompression method without causing electrolyte and nutritional losses.

    Aims: The aim is to study the efficacy of VSGS for temporary CSF diversion, compared to extraventricular drainage (EVD) in adult hydrocephalus patients; to evaluate the outcome in terms of avoiding a permanent shunt, and to look for incidences of their complications.

    Settings and Design: This was a retrospective observational study.

    Subjects and Methods: The data were acquired from case notes of fifty patients with acute hydrocephalus: 26 secondary to IVH, 10 from aneurysm rupture, 8 posttrauma, and 6 from infection. All these patients had undergone CSF diversion in Hospital Queen Elizabeth II, Sabah, Malaysia, between 2013 and 2015. The patients were followed up from the date of treatment until the resolution of hydrocephalus, where parameters such as shunt dependency and complications were documented.

    Statistical Analysis Used: All analyses were carried out using Statistical Packages for the Social Sciences Version 22.0. Chi-squared test or Fisher's exact test is used for univariate analysis of categorical variables.

    Results: A total of 21 (42%) patients underwent EVD insertion and 29 (58%) underwent VSGS insertion. Thirty-seven (74%) patients did not require a permanent shunt; 24 (64.8%) of them were from the VSGS group (P = 0.097). EVD had more intracranial complications (44.1%) compared with VSGS (23.5%), with a statistically significant P = 0.026.

    Conclusions: VSGS is a safe and viable option for adult hydrocephalus patients, with the possibility of continuation of the treatment for such patients in nonneurosurgical centers, as opposed to patients with EVDs. Furthermore, even though this method had no statistical difference in avoiding a permanent ventriculoperitoneal shunt, VSGS has statistically significant less intracranial complications compared with EVD.
    Matched MeSH terms: Electrolytes
  12. Benign afebrile convulsion with gastroenteritis - A differential to consider for afebrile seizure in children
    Ng RL
    Med J Malaysia, 2018 10;73(5):328-329.
    PMID: 30350815
    A 5-year-old girl presented with three brief episodes of afebrile seizure within 24 hours. There was no significant past medical history but she had symptoms of acute gastroenteritis for the past 2 days. She was mildly dehydrated with no neurological signs. Serum electrolytes and blood sugar were normal and cerebrospinal fluid examination was negative for meningoencephalitis. Contrast-enhanced CT Brain showed no evidence of intracranial lesion, haemorrhage or meningeal enhancement. Only stool investigation was positive for Rotavirus. The conclusion of Benign Afebrile Convulsion with gastroenteritis (CwG) was established after excluding other serious causes of afebrile seizure in children.
    Matched MeSH terms: Electrolytes
  13. Fulltext Electrochemically synthesized si nanowire arrays and thermoelectric nanostructures
    Ng, Inn Khuan, Kok, Kuan Ying, Nur Ubaidah Saidin, Choo, Thye Foo
    Journal of Nuclear and Related Technologies, 2012;2012(2):34-40.
    MyJurnal
    Thermoelectric nanostructures hold great promise for capturing and directly converting into electricity some vast amount of low-grade waste heats now being lost to the environment (e.g. from nuclear power plant, fossil fuel burning, automotives and household appliances). In this study, large-area vertically-aligned silicon nanowire (SiNW) arrays were synthesized in an aqueous solution containing AgN•i and HF on p-type Si (100) substrate by self-selective electroless etching process. The etching conditions were systematically varied in order to achieve different stages of nanowire formation. Diameters of the SiNWs obtained varied from approximately 50 to 200 nm and their lengths ranged from several to a few tens of um. Te/Bi2Tex.Si thermoelectric core-shell nanostructures were subsequently obtained via galvanic displacement of SiNWs in acidic HF electrolytes containing HTe02+ and 139' /HTe02+ ions. The reactions were basically a nano-electrochemical process due to the difference in redox potentials between the materials. The surface-modified SiNWs of core-shell structures had roughened surface morphologies and, therefore, higher surface-to-bulk ratios compared to unmodified SiNWs. They have potential applications in sensors, photovoltaic and thermoelectric nanodevices. Growth study on the SiNWs and core-shell nanostructures produced is presented using various microscopy, diffraction and probe-based techniques for microstructural, morphological and chemical characterizations.
    Matched MeSH terms: Electrolytes
  14. Fulltext DETERMINATION OF REACTIVE BLACK 5 (RB5) BY DIFFERENTIAL PULSE ANODIC STRIPPING VOLTAMMETRIC TECHNIQUE
    Nur Syamimi Zainudin, Nur Aqilah Abdul Rahman
    Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2021;9(1):73-79.
    MyJurnal
    Dyes are aromatic organic compound which have an affinity towards the substrate to which they are being applied to. The presence of dyes in wastewater samples is not safe for human even at low level. The presence of dyes in wastewater which are discharged from textile industry must be analysed. Hence, a precise, fast, accurate, simple and inexpensive analytical method with low detection limit is needed for the determination of dyes in wastewaters. The differential pulse anodic stripping voltammetric (DPASV) technique using bare glassy carbon electrode (GCE) as a working electrode and phosphate buffer at pH 4.2 as a supporting electrolyte has been proposed for Reactive Black 5 (RB5) determination. Several experimental voltammetric parameters were being optimized for obtaining a maximum response before analytical validation of the proposed technique being carried out. The optimum parameters were initial potential (Ei) = +0.3 V, end potential (Ef) = +1.0 V, scan rate (v) = 0.04 V/s, accumulation time (tacc) = 50 s, accumulation potential (Eacc) = 0.4 V and pulse amplitude = 0.075 V. The well-defined anodic peak appeared at 0.77972 V. The response was linear from 0.5 to 1.25 mg/L (R2=0.9986) with LOD of 0.050 mg/L. The relative standard deviation (RSD) achieved were 0.08 %, 0.62 % and 0.50 %, respectively for three consecutive days. The % recovery range achieved was from 89.71 % to 111.15 %. It can be concluded that the proposed technique is precise, accurate, inexpensive, fast and has a potential to be an alternative analytical technique for RB5 analysis. The proposed method will in the future be tested for the amount of RB5 in the wastewater samples from textile industry.
    Matched MeSH terms: Electrolytes
  15. Fulltext Physical and conductivity studies of plasticised Methyl Cellulose-Lithium Triflate based polymer electrolyte
    Nursyahida Sahli, Nordiana Nabilla Ramly, Muhd Zu Azhan Yahya, Ab Malik Marwan Ali
    Pertanika Journal of Science & Technology, 2017;25(103):183-190.
    MyJurnal
    Solid polymer electrolyte based on methyl cellulose (MC)-lithium triflate (LiCF3SO3) plasticised with ethylene carbonate (EC) was prepared using solution cast technique. The X-ray diffraction (XRD) studies proved that the amorphous nature of the electrolyte systems was increases due to the addition of salt and plasticiser. The improved surface morphology of plasticised polymer system ensures it has good electrode-electrolyte contact during performance testing. The polymer electrolyte was found to have high thermal stability indicating that the electrolyte can be used at higher temperature. The ionic conductivity increased up to 1.24 x 10-4 S cm-1 at optimum amount of EC plasticiser associated to the effect of plasticiser that initially leads to the formation of Li+-EC complex. Consequently, it reduces the fraction of polymer-Li+ complex which contributes to the increase of the segmental chain flexibility in the plasticized system. Temperature dependent studies indicate ionic conductivity increase due to the temperature increase and is in line with Arrhenius behaviour pattern. An activation energy of 0.26 eV at highest conductivity sample was obtained. The addition of plasticiser lowers the activation energy thus increasing the ion mobility of the system and contributing to ionic conductivity increment. The plasticization method is a promising means to dealing with the solid polymer electrolyte problem and producing electrolytes that meet the needs of electrochemical devices.
    Matched MeSH terms: Electrolytes
  16. A synergistic heterostructured ZnO/BaTiO3 loaded carbon photoanode in photocatalytic fuel cell for degradation of Reactive Red 120 and electricity generation
    Ong YP, Ho LN, Ong SA, Banjuraizah J, Ibrahim AH, Lee SL, et al.
    Chemosphere, 2019 Mar;219:277-285.
    PMID: 30543963 DOI: 10.1016/j.chemosphere.2018.12.004
    Photocatalytic fuel cell (PFC) is considered as a sustainable green technology which could degrade organic pollutant and generate electricity simultaneously. A synergistic double-sided ZnO/BaTiO3 loaded carbon plate heterojunction photoanode was fabricated in different ratios by using simple ultrasonication and mixed-annealed method. The double-sided design of photoanode allowed the lights irradiated at both sides of the photoanode. The ferroelectricity fabricated photoanode was applied in a membraneless PFC with platinum-loaded carbon as the cathode. Results revealed that the photoanode with 1:1 ratio of BaTiO3 and ZnO exhibited a superior photocatalytic activity among all the photoanodes prepared in this study. The heterojunction of this photoanode was able to achieve up to a removal efficiency of 93.67% with a maximum power density of 0.5284 μW cm-2 in 10 mg L-1 of Reactive Red 120 (RR120) without any supporting electrolyte. This photoanode was able to maintain at high performance after recycling 3 times. Overloading of ZnO above 50% on BaTiO3 could lead to deterioration of the performance of PFC due to the charge defects and light trapping ability. The interactions, interesting polarizations of the photocatalysts and proposed mechanism of the n-n type heterojunction in the photoanode of ZnO/BaTiO3 was also discussed.
    Matched MeSH terms: Electrolytes
  17. Fulltext Ionic conductivity and morphological studies of plasticized poly (methyl methacrylate) polymer electrolyte films
    Osman, Z., Othman, L., Md Isa, K.B., Ahmad, A., Kamarulzaman, N.
    ASM Science Journal, 2010;4(1):55-61.
    MyJurnal
    In this study polymer electrolytes composed of poly(methyl methacrylate) (PMMA) as a host polymer and ethylene carbonate (EC) as a plasticizer complexed with different lithium salts, i.e. lithium tetrafluoroborate (LiBF4) and lithium triflate (LiCF3SO3) were prepared by the solution casting technique. The conductivities of the films were characterized by impedance spectroscopy. At room temperature, the highest conductivities were 4.07 × 10–7S cm–1 and 3.40 × 10–5 S cm–1 achieved, respectively from the films containing 30 wt% LiBF4 in the PMMA-EC-LiBF4 system and 35 wt% LiCF3SO3 in the PMMA-EC-LiCF3SO3 system. The conductivity-temperature dependence of the films seemed to obey the Arrhenius equation in which the ion transport in these materials was thermally assisted. Scanning electron microscopy analysis showed that the surface of PMMA-EC-LiCF3SO3 film was smooth and homogeneous, hence lithium ions could traverse through the PMMA-EC-LiCF3SO3 film more easily compared to the PMMA-EC-LiBF4 film. X-Ray diffraction studies revealed that complexation had occurred and the complexes formed were amorphous.
    Matched MeSH terms: Electrolytes
  18. Fulltext Electrodeposited Porous Mn1.5Co1.5O₄/Ni Composite Electrodes for High-Voltage Asymmetric Supercapacitors
    Pan GT, Chong S, Yang TC, Huang CM
    Materials (Basel), 2017 Mar 31;10(4).
    PMID: 28772727 DOI: 10.3390/ma10040370
    Mesoporous Mn1.5Co1.5O₄ (MCO) spinel films were prepared directly on a conductive nickel (Ni) foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni)-15 min electrode (electrodeposition time: 15 min) exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively). Further, an asymmetric supercapacitor that utilizes (MCO/Ni)-15 min as a positive electrode, a plasma-treated activated carbon (PAC)/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO₃) gel electrolyte (denoted as (PAC/Ni)//(MCO/Ni)-15 min) was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg-1 and a power density of 1.01 kW·kg-1 at 1 A·g-1. After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni)//(MCO/Ni)-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni)-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling.
    Matched MeSH terms: Electrolytes
  19. Fulltext Synthesis and characterizations of o-nitrochitosan based biopolymer electrolyte for electrochemical devices
    Rahman NA, Abu Hanifah S, Mobarak NN, Su'ait MS, Ahmad A, Shyuan LK, et al.
    PLoS One, 2019;14(2):e0212066.
    PMID: 30768616 DOI: 10.1371/journal.pone.0212066
    For the past decade, much attention was focused on polysaccharide natural resources for various purposes. Throughout the works, several efforts were reported to prepare new function of chitosan by chemical modifications for renewable energy, such as fuel cell application. This paper focuses on synthesis of the chitosan derivative, namely, O-nitrochitosan which was synthesized at various compositions of sodium hydroxide and reacted with nitric acid fume. Its potential as biopolymer electrolytes was studied. The substitution of nitro group was analyzed by using Attenuated Total Reflectance Fourier Transform Infra-Red (ATR-FTIR) analysis, Nuclear Magnetic Resonance (NMR) and Elemental Analysis (CHNS). The structure was characterized by X-ray Diffraction (XRD) and its thermal properties were examined by using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Whereas, the ionic conductivity of the samples was analyzed by electrochemical impedance spectroscopy (EIS). From the IR spectrum results, the nitro group peaks of O-nitrochitosan, positioned at 1646 and 1355 cm-1, were clearly seen for all pH media. At pH 6, O-nitrochitosan exhibited the highest degree of substitution at 0.74 when analyzed by CHNS analysis and NMR further proved that C-6 of glucosamine ring was shifted to the higher field. However, the thermal stability and glass transition temperatures were decreased with acidic condition. The highest ionic conductivity of O-nitrochitosan was obtained at ~10-6 cm-1. Overall, the electrochemical property of new O-nitrochitosan showed a good improvement as compared to chitosan and other chitosan derivatives. Hence, O-nitrochitosan is a promising biopolymer electrolyte and has the potential to be applied in electrochemical devices.
    Matched MeSH terms: Electrolytes/chemical synthesis; Electrolytes/chemistry*
  20. Fulltext Effect of solution pH and adsorbent concentration on the sensing parameters of TGN-based electrochemical sensor
    Rahmani M, Ghafoorifard H, Afrang S, Ahmadi MT, Rahmani K, Ismail R
    IET Nanobiotechnol, 2019 Aug;13(6):584-592.
    PMID: 31432790 DOI: 10.1049/iet-nbt.2018.5288
    The response of trilayer graphene nanoribbon (TGN)-based ion-sensitive field-effect transistor (ISFET) to different pH solutions and adsorption effect on the sensing parameters are analytically studied in this research. The authors propose a TGN-based sensor to electrochemically detect pH. To this end, absorption effect on the sensing area in the form of carrier concentration, carrier velocity, and conductance variations are investigated. Also, the caused electrical response on TGN as a detection element is analytically proposed, in which significant current decrease of the sensor is observed after exposure to high pH values. In order to verify the accuracy of the model, it is compared with recent reports on pH sensors. The TGN-based pH sensor exposes higher current compared to that of carbon nanotube (CNT) counterpart for analogous ambient conditions. While, the comparative results demonstrate that the conductance of proposed model is lower than that of monolayer graphene-counterpart for equivalent pH values. The results confirm that the conductance of the sensor is decreased and Vg-min is obviously right-shifted by increasing value of pH. The authors demonstrate that although there is not the experimental evidence reported in the part of literature for TGN sensor, but the model can assist in comprehending experiments involving nanoscale pH sensors.
    Matched MeSH terms: Electrolytes/chemistry*
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