Mechanistic insights into the activation process in electrocatalytic ethanol oxidation by phosphomolybdic acid-stabilised palladium(0) nanoparticles (PdNPs@PMo12)

RSC Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 5359-5366 ◽  
Author(s):  
Sara Khadempir ◽  
Ali Ahmadpour ◽  
Mohammad Taghi Hamed Mosavian ◽  
Narges Ashraf ◽  
Fatemeh F. Bamoharram ◽  
...  
Keyword(s):  
Ethanol Oxidation ◽  
Phosphomolybdic Acid ◽  
Activation Process ◽  
Keggin Type

A Keggin type polyoxometalate (POM), phosphomolybdic acid (PMo12), has been employed to encapsulate and stabilise pseudo-spherical Pd(0) nanoparticles (PdNPs).

Identification and Electroanalytical Characterization of Redox Transitions in Solid-State Keggin type Phosphomolybdic Acid

2005 ◽  
Vol 17 (15-16) ◽  
pp. 1471-1476 ◽  
Author(s):  
Adam Lewera ◽  
Malgorzata Chojak ◽  
Krzysztof Miecznikowski ◽  
Pawel J. Kulesza
Keyword(s):  
Solid State ◽  
Phosphomolybdic Acid ◽  
Keggin Type ◽  
Redox Transitions

PEG400 Modification of Keggin-Type H4PMo11VO40-Based Catalysts for the Selective Oxidation of Methacrolein to Methacrylic Acid

2012 ◽  
Vol 550-553 ◽  
pp. 252-256 ◽  
Author(s):  
Li Yang ◽  
Heng Zhang ◽  
Rui Yi Yan ◽  
Xiang Ping Zhang ◽  
Guang Jin Zhang ◽  
...  
Keyword(s):  
Selective Oxidation ◽  
Methacrylic Acid ◽  
Phosphomolybdic Acid ◽  
Catalytic Performance ◽  
Optimum Conditions ◽  
Heteropoly Anion ◽  
Keggin Type ◽  
Surface Areas ◽  
Ft Ir ◽  
Specific Surface Areas

Keggin-type 12-phosphomolybdic acid with molybdenum partially substituted by vanadium and protons partially substituted by alkali and transition metals was synthesized for the selective oxidation of methacrolein to methacrylic acid. The structures of the catalysts were studied by FT-IR, XRD, TG-DTA and BET. The effects of the additive amount of PEG400, calcination temperature and the content of Cs on the catalytic performance were investigated. Results show that specific surface areas of the catalysts increase with the increase of PEG400 amount; PEG400 is removed at 250 °C and the primary structure of the catalysts is not changed with the addition of PEG400. The conversion and selectivity increase with the Cs content, and then decrease. The catalyst with the ratio of Cs+: heteropoly anion=1:1 exhibits good catalytic performance for the selective oxidation of MAL. Under the optimum conditions, the conversion of MAL and selectivity of MAA are 76.4% and 83.6% respectively.

SEM and Auger microanalysis studies of Cu-Be dynode surfaces at each activation condition

1978 ◽  
Vol 36 (1) ◽  
pp. 524-525
Author(s):  
T. Koshikawa ◽  
Y. Fujii ◽  
E. Sugata ◽  
F. Kanematsu
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Life Time ◽  
Activation Process ◽  
Beam Diameter ◽  
Activation Temperature ◽  
Electron Multiplier ◽  
Activation Condition ◽  
Activation Conditions

The Cu-Be alloys are widely used as the electron multiplier dynodes after the adequate activation process. But the structures and compositions of the elements on the activated surfaces were not studied clearly. The Cu-Be alloys are heated in the oxygen atmosphere in the usual activation techniques. The activation conditions, e.g. temperature and O2 pressure, affect strongly the secondary electron yield and life time of dynodes.In the present paper, the activated Cu-Be dynode surfaces at each condition are investigated with Scanning Auger Microanalyzer (SAM) (primary beam diameter: 3μmϕ) and SEM. The commercial Cu-Be(2%) alloys were polished with Cr2O3 powder, rinsed in the distilled water and set in the vacuum furnance.Two typical activation condition, i.e. activation temperature 730°C and 810°C in 5x10-3 Torr O2 pressure were chosen since the formation mechanism of the BeO film on the Cu-Be alloys was guessed to be very different at each temperature from the results of the secondary electron emission measurements.

The Binding of Calcium Ions to Bovine Factor X by Rate Dialysis

1978 ◽  
Vol 40 (02) ◽  
pp. 350-357
Author(s):  
Robert H Yue ◽  
Menard M Gertler
Keyword(s):  
Molecular Weight ◽  
Dissociation Constant ◽  
Calcium Ions ◽  
Activation Process ◽  
Factor X ◽  
The Real ◽  
High Affinity ◽  
Binding Data ◽  
Sequential Mechanism ◽  
Bovine Factor

SummaryThe binding of Ca+2 to bovine factor X (molecular weight of 74,000) (Yue und Gertler 1977) was studied by the technique of rate dialysis and with the use of 45Ca+2. The binding data are consistent with a model of sequential mechanism. One mole of Ca+2 binds to the glycoprotein with a dissociation constant of 5.2 × 10-5 M and an additional 39 ± 4 moles of Ca+2 bind to this zymogen with a dissociation constant of 3.7 × 10-3M. The binding of the high affinity Ca+2 causes a functionally significant change in the zymogen, and (calcium) (factor X) complex is the real substrate in the activation process by the protease in Russell’s viper venom.

Ethanol Metabolism in Vivo and the Role of Hepatic Microsomal Ethanol Oxidation

1972 ◽  
Vol 33 (3) ◽  
pp. 751-755 ◽  
Author(s):  
Mary K. Roach ◽  
Myrna Khan ◽  
Marguerite Knapp ◽  
W. N. Reese
Keyword(s):  
Ethanol Oxidation ◽  
Ethanol Metabolism

COMPARISON OF VARIOUS METHODS FOR THE CHEMICAL ASSAY OF CORTICOIDS IN URINE

1955 ◽  
Vol 18 (4) ◽  
pp. 374-378
Author(s):  
Mogens Sprechler
Keyword(s):  
Calibration Curve ◽  
Periodic Acid ◽  
Reducing Power ◽  
Standard Technique ◽  
Phosphomolybdic Acid ◽  
Florisil Column ◽  
Chemical Assay ◽  
Chromatographic Procedure ◽  
Acid Reagent

SUMMARY Since 1949 about 10,000 urinary corticoid analyses have been performed routinely in our laboratory. The method used for this purpose was described in 1950 (Sprechler). We determine the corticoids which can be extracted from the urine with chloroform immediately after acidification to pH 1. The extract is washed with sodium hydroxide and water, a Girard separation is performed, and finally the reducing power of the ketonic fraction is measured by means of the phosphomolybdic acid reagent reaction. During the last few years two other chemical reactions have been used for comparison: The formaldehyde and the Porter-Silber method. After a thorough examination of the above methods a standard technique was followed. In the formaldehyde method a microdiffusion in a Conway unit was used instead of distillation of the formaldehyde following the oxidation with periodic acid. The calibration curve was corrected for loss of material by taking the standard doses of DOC through all the procedures of the method. A micromodification of the Porter-Silber method was chosen. Furthermore attempts were made to determine how specific the chromatographic procedure is in the determination of steroids in urinary extracts. For this purpose the Florisil column was used, and the technique described by Nelson & Samuels was followed. Finally we have investigated the glucuronide-bound corticoids in urine in a smaller series of objects.

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