The Effect of Ru on Unsupported Pt-Ru Alloys for Methanol Electro-Oxidation at Different Temperatures

1995 ◽  
Vol 393 ◽  
Author(s):  
Deryn Chu ◽  
Charles Walker ◽  
Sol Gilman
Keyword(s):  
Cyclic Voltammetry ◽  
Sulfuric Acid ◽  
Surface Area ◽  
Hydrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Adsorption Surface ◽  
Electro Oxidation ◽  
Bulk Alloys

ABSTRACTUnsupported different atomic ratios of platinum-ruthenium bulk alloys were prepared. The alloys were characterized by cyclic voltammetry, X-ray diffraction and energy dispersive X-ray spectroscopy. These alloys were also tested as anodes for methanol electro-oxidation in sulfuric acid over a range of temperatures. Ruthenium is inactive for methanol electro-oxidation at 25 °C, but becomes active at higher temperatures. When a comparison is made on the basis of “true” (hydrogen adsorption) surface area, a 30 atomic percent Ru electrocatalyst provides the highest activity for methanol electro-oxidation as measured at either 0.4 or 0.5V vs. RHE at both 25 and 60 °C.

Electro-Oxidation of Ethanol on the Preparation of Electroless Ni-P Alloy Electrode

2011 ◽  
Vol 311-313 ◽  
pp. 1361-1364
Author(s):  
Shu Guang Xie ◽  
Zhan Chang Pan ◽  
Guang Hui Hu ◽  
Zhi Gang Wei ◽  
Chu Min Xiao ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Catalytic Effect ◽  
Electrochemical Impedance ◽  
Textural Properties ◽  
Alloy Electrode ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electro Oxidation ◽  
Electroless Ni ◽  
Oxidation Of Ethanol

Ni-P alloy electrode was prepared by electroless plating on the Cu-Zn substrate. The surface morphology and textural properties of electrode were characterized by Scanning electron microscope(SEM), Energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD). The performance of Ni-P alloy electrode was tested by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy.The results of cyclic voltammetry showed that: At room temperature, Ni-P alloy electrode had significant catalytic effect on the electrocatalytic oxidation of ethanol in alkaline solution. Results of chronoamperometry and electrochemical impedance spectroscopy further confirmed the catalytic effect of Ni-P alloy electrode on the electrochemical oxidation of ethanol.

scholarly journals Effect of KOH Activator on the Performance of Activated Carbon from Oil Palm Kernel Shell as Supercapacitor Electrode Material

2020 ◽  
Vol 9 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Yola Azli Perdana ◽  
Rahma Joni ◽  
Emriadi Emriadi ◽  
Hemansyah Aziz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cyclic Voltammetry ◽  
Activated Carbon ◽  
Surface Area ◽  
Palm Kernel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Palm Kernel Shell ◽  
Scanning Electron

Karbon aktif dari cangkang kelapa sawit sebagai bahan elektroda superkapasitor telah diteliti. Superkapasitor dirangkai dengan metoda plat/sandwich yang dipisahkan oleh separator. Untuk mendapatkan nilai kapasitansi yang besar dilakukan variasi jumlah aktivator terhadap karbon menggunakan aktivator KOH. Sifat fisikokimia dari karbon aktif diteliti dengan melakukan karakterisasi menggunakan XRD (X-Ray Diffraction), SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-Ray) dan SAA (Surface Area Analyzer) dan sifat elektrokimianya diteliti dengan pengukuran CV (Cyclic Voltammetry). Karbon aktif dengan perbandingan 1:5 memiliki luas permukaan yang paling besar yaitu 793,326 m2/g dan nilai kapasitansi spesifik tertinggi yaitu 99,151 F/g. The activated carbon from oil palm kernel shell as an electrode material for supercapacitors has been investigated. The supercapasitor was assembled by plate/sandwich methods. Both electrodes were separated by using a separator. To increase the capacitancy value, variations in the number of activators on carbon were carried out using KOH activator. The physicochemical properties of activated carbon were investigated by characterizing using XRD (X-Ray Diffraction), SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-Ray) and SAA (Surface Area Analyzer) and the electrochemical properties were investigated by measuring CV (Cyclic Voltammetry). Activated carbon with a ratio of 1:5 has the largest surface area of 793,326 m2/g and the highest specific capacitance value is 99,151 F/g.Keywords: activated carbon, supercapasitor, activator, surface area, specific capacitance

The Preparation of Bi-Pb-Sr-Ca-Cu-O Superconducting Powder for Thick Film Pastes

1989 ◽  
Vol 169 ◽  
Author(s):  
J. Hagberg ◽  
A. Uusimäki ◽  
J. Levoska ◽  
S Leppävuori ◽  
R Rautioaho
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Surface Area ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Oxalate Route

AbstractThe oxalate route was used to prepare (Bi-Pb) -Sr-Ca-Cu-O powder with the nominal composition Bi1.75Pb0.4Sr1.3Ca2.1Cu3.2Oy. This powder was decomposed/annealed at different temperatures between 434 and 795°C. They were investigated by thermogravimetric analysis, X-ray diffraction and transmission electron microscopy. Particle size distribution and surface area were also determined. The specific surface area decreased from a value of 16.5 m2/g for powder decomposed at 434 °C to 1.0 m2/g for powder decomposed at 795 °C. The measured mean particle size reached a minimum of 0.52 juri for powder decomposed at 589 °C.

Hydrophobic Ferrocene Derivatives as Potential Standards in Electrochemistry

1997 ◽  
Vol 62 (2) ◽  
pp. 185-198 ◽  
Author(s):  
Jaroslav Podlaha ◽  
Petr Štěpnička ◽  
Róbert Gyepes ◽  
Vladimír Mareček ◽  
Alexander Lhotský ◽  
...  
Keyword(s):  
Surface Tension ◽  
Cyclic Voltammetry ◽  
Redox Potential ◽  
Diffusion Coefficients ◽  
Carbon Electrodes ◽  
X Ray Diffraction ◽  
Ferrocene Derivatives ◽  
X Ray ◽  
Special Cases ◽  
As Solubility

Ferrocene (FcH) derivatives monosubstituted by palmitoyl (1), hexadecyl (2), 1-adamantoyl (3) or 1-adamantylmethyl (4) groups were sythesized and characterized by NMR, mass and 57Fe Mossbauer spectroscopy. The structure of 1-adamantoylferrocene was determined by single-crystal X-ray diffraction. Cyclic voltammetry on gold and glass-like carbon electrodes demonstrated that the compounds can serve as electrochemical standards for special cases since their ferrocene/ferricinium redox potential remains stable and reversible, while the properties such as solubility, diffusion coefficients and surface tension are strongly solvent-dependent.

scholarly journals Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1238
Author(s):  
Garven M. Huntley ◽  
Rudy L. Luck ◽  
Michael E. Mullins ◽  
Nick K. Newberry
Keyword(s):  
New Mexico ◽  
Surface Area ◽  
Bet Surface Area ◽  
Lead Removal ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Naturally Occurring ◽  
27Al Mas Nmr ◽  
Modified Zeolites

Four naturally occurring zeolites were examined to verify their assignments as chabazites AZLB-Ca and AZLB-Na (Bowie, Arizona) and clinoptilolites NM-Ca (Winston, New Mexico) and NV-Na (Ash Meadows, Nevada). Based on powder X-ray diffraction, NM-Ca was discovered to be mostly quartz with some clinoptilolite residues. Treatment with concentrated HCl (12.1 M) acid resulted in AZLB-Ca and AZLB-Na, the chabazite-like species, becoming amorphous, as confirmed by powder X-ray diffraction. In contrast, NM-Ca and NV-Na, which are clinoptilolite-like species, withstood boiling in concentrated HCl acid. This treatment removes calcium, magnesium, sodium, potassium, aluminum, and iron atoms or ions from the framework while leaving the silicon framework intact as confirmed via X-ray fluorescence and diffraction. SEM images on calcined and HCl treated NV-Na were obtained. BET surface area analysis confirmed an increase in surface area for the two zeolites after treatment, NM-Ca 20.0(1) to 111(4) m2/g and NV-Na 19.0(4) to 158(7) m2/g. 29Si and 27Al MAS NMR were performed on the natural and treated NV-Na zeolite, and the data for the natural NV-Na zeolite suggested a Si:Al ratio of 4.33 similar to that determined by X-Ray fluorescence of 4.55. Removal of lead ions from solution decreased from the native NM-Ca, 0.27(14), NV-Na, 1.50(17) meq/g compared to the modified zeolites, 30 min HCl treated NM-Ca 0.06(9) and NV-Na, 0.41(23) meq/g, and also decreased upon K+ ion pretreatment in the HCl modified zeolites.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

scholarly journals Hydrothermal Ageing and Its Effect on Fracture Load of Zirconia Dental Implants

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3103
Author(s):  
Laurent Gremillard ◽  
Agnès Mattlet ◽  
Alexandre Mathevon ◽  
Damien Fabrègue ◽  
Bruno Zberg ◽  
...  
Keyword(s):  
Dental Implants ◽  
Fracture Load ◽  
Accelerated Ageing ◽  
Dental Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dental Restorations ◽  
Different Temperatures ◽  
Mechanical Performances ◽  
Kinetics Of

Due to growing demand for metal-free dental restorations, dental ceramics, especially dental zirconia, represent an increasing share of the dental implants market. They may offer mechanical performances of the same range as titanium ones. However, their use is still restricted by a lack of confidence in their durability and, in particular, in their ability to resist hydrothermal ageing. In the present study, the ageing kinetics of commercial zirconia dental implants are characterized by X-ray diffraction after accelerated ageing in an autoclave at different temperatures, enabling their extrapolation to body temperature. Measurements of the fracture loads show no effect of hydrothermal ageing even after ageing treatments simulated a 90-year implantation.

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

Physico-Chemical and Morphological Changes of Sayong Kaolinite Clay Treated with Sulphuric Acid for Enzyme Immobilization

2013 ◽  
Vol 832 ◽  
pp. 589-595 ◽  
Author(s):  
N.A. Edama ◽  
A. Sulaiman ◽  
K.H. Ku Hamid ◽  
M.N. Muhd Rodhi ◽  
Mohibah Musa ◽  
...  
Keyword(s):  
Surface Area ◽  
Sulphuric Acid ◽  
Enzyme Immobilization ◽  
Morphological Changes ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Kaolinite Clay ◽  
X Ray ◽  
Mineral Oxides ◽  
Physico Chemical

This study analyzed the effects of sulphuric acid (H2SO4) treatment on pysico-chemical properties and morphological changes of clay obtained from Sg. Sayong, Perak. The clay was ground and sieved to <150μm and treated with different concentrations of H2SO4. The treatment was completed by refluxing the clay with different concentration of H2SO4 (1M, 5M and 10M ) at 100 °C for 4 hours and followed by calcination at 500 °C for 1 hour. The physic-chemical properties and morphological changes of the untreated and treated clay were compared using Surface Area Analyser, X-Ray Diffraction (XRD), Field Emission Scanning Electron Micrograph (FESEM), X-Ray Diffraction (XRD) and Fourier Transformed Infrared Spectroscopy (FTIR). The results showed that acid treatment of 5M increased the surface area from 25 m2/g to 75 m2/g and the pore volume increased from 0.1518 cc/g to 0.3546 cc/g. The nanopore size of the clay decreased from 24.8 nm to 19.4 nm after treated with acid. This can be explained due to the elimination of the exchangeable cations and generation of microporosity. The results of XRF showed SiO2 increased from 58.34% to 74.52% and Al2O3 reduced from 34.6% to 18.31%. The mineral oxides such as Fe2O3, MgO, CaO, K2O and TiO2 also reduced. This concluded that H2SO4 treatment has led to significant removal of octahedral Al3+, Fe3+ cations and other impurities. In conclusion, this study showed the physico-chemical properties and morphology of Sayong clay were improved once treated with H2SO4 and therefore suggests better supporting material for enzyme immobilization.

Hydrothermal Treatment of Coprecipitated YSZ Powders

2010 ◽  
Vol 660-661 ◽  
pp. 983-988 ◽  
Author(s):  
Alexander Rodrigo Arakaki ◽  
Walter Kenji Yoshito ◽  
Valter Ussui ◽  
Dolores Ribeiro Ricci Lazar
Keyword(s):  
Surface Area ◽  
Hydrothermal Treatment ◽  
Gas Adsorption ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
Immersion Method ◽  
Cubic Symmetry ◽  
X Ray ◽  
Granulometric Analysis ◽  
Symmetry Surface

Zirconia stabilized with 8.5 mol% yttria (YSZ) were synthesized by coprecipitation and resulting gels were hydrothermallly treated at 200°C and 220 PSI for 4, 8 and 16 hours. Products were oven dried at 70°C for 24 hours, isostatically pressed as pellets and sintered at 1500 °C for 1 hour. Powders were characterized for surface area with N2 gas adsorption, X-ray diffraction, laser diffraction granulometric analysis and scanning and transmission electronic microscopy. Density of ceramics was measured by an immersion method based on the Archimedes principle. Results showed that powders dried at 70°C are amorphous and after treatment has tetragonal/cubic symmetry. Surface area of powders presented a significant reduction after hydrothermal treatment. Ceramics prepared from hydrothermally treated powders have higher green density but sintered pellets are less dense when compared to that made with powders calcined at 800°C for 1 hour due to the agglomerate state of powders. Solvothermal treatment is a promising procedure to enhance density.

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