scholarly journals Studies on the Formation of Catalytically Active PGM Nanoparticles from Model Solutions as a Basis for the Recycling of Spent Catalysts

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 390
Author(s):  
Martyna Rzelewska-Piekut ◽  
Zuzanna Wiecka ◽  
Magdalena Regel-Rosocka
Keyword(s):  
Ascorbic Acid ◽  
Sodium Borohydride ◽  
Catalytic Reaction ◽  
Sodium Formate ◽  
Ruthenium Nanoparticles ◽  
Acidic Solutions ◽  
Two Component ◽  
Catalytically Active ◽  
Spent Catalysts ◽  
Basic Studies

The paper presents basic studies on the precipitation of platinum, palladium, rhodium, and ruthenium nanoparticles from model acidic solutions using sodium borohydride, ascorbic acid, and sodium formate as reducing agents and polyvinylpyrrolidone as a stabilizing agent. The size of the obtained PGM particles after precipitation with NaBH4 solution does not exceed 55 nm. NaBH4 is an efficient reducer; the precipitation yields for Pt, Pd, Ru, Rh are 75, 90, 65 and 85%, respectively. By precipitation with ascorbic acid, it is possible to efficiently separate Pt, Rh, and Ru from Pd from the two-component mixtures. The obtained Pt, Pd, and Rh precipitates have the catalytic ability of the catalytic reaction of p-nitrophenol to p-aminophenol. The morphological characteristic of the PGM precipitates was analyzed by AFM, SEM-EDS, and TEM.

Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Mai Ngọc Tuan Anh
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Ascorbic Acid ◽  
Silver Nitrate ◽  
Sodium Borohydride ◽  
Trisodium Citrate ◽  
Synthesis And Characterization ◽  
Silver Nanoplates ◽  
Seed Mediated

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag\(^+\) ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

scholarly journals Selectivity control in hydrogenation through adaptive catalysis using ruthenium nanoparticles on a CO2-responsive support

2021 ◽  
Author(s):  
Alexis Bordet ◽  
Sami El Sayed ◽  
Matthew Sanger ◽  
Kyle J. Boniface ◽  
Deepti Kalsi ◽  
...  
Keyword(s):  
Real Time ◽  
Carbonyl Group ◽  
Catalytic Reaction ◽  
Renewable Resources ◽  
Gas Composition ◽  
Ruthenium Nanoparticles ◽  
Catalytic Systems ◽  
Amine Functionalized ◽  
Hydrogenation Reactions ◽  
Selectivity Control

AbstractWith the advent of renewable carbon resources, multifunctional catalysts are becoming essential to hydrogenate selectively biomass-derived substrates and intermediates. However, the development of adaptive catalytic systems, that is, with reversibly adjustable reactivity, able to cope with the intermittence of renewable resources remains a challenge. Here, we report the preparation of a catalytic system designed to respond adaptively to feed gas composition in hydrogenation reactions. Ruthenium nanoparticles immobilized on amine-functionalized polymer-grafted silica act as active and stable catalysts for the hydrogenation of biomass-derived furfural acetone and related substrates. Hydrogenation of the carbonyl group is selectively switched on or off if pure H2 or a H2/CO2 mixture is used, respectively. The formation of alkylammonium formate species by the catalytic reaction of CO2 and H2 at the amine-functionalized support has been identified as the most likely molecular trigger for the selectivity switch. As this reaction is fully reversible, the catalyst performance responds almost in real time to the feed gas composition.

Hydrogen generation by both acidic and catalytic hydrolysis of sodium borohydride

2018 ◽  
Vol 5 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Olga V. Netskina ◽  
Tihon N. Filippov ◽  
Oksana V. Komova ◽  
Valentina I. Simagina
Keyword(s):  
Hydrogen Evolution ◽  
Sodium Borohydride ◽  
Hydrogen Generation ◽  
Hydrogen Release ◽  
Catalytic Hydrolysis ◽  
Hydrogen Storage Materials ◽  
Acidic Solutions ◽  
High Concentrations ◽  
Sulfuric And Hydrochloric Acids ◽  
Hydrolysis Of

Abstract Sodium borohydride tablets have been employed as hydrogen-storage materials. Hydrogen release was performed by acidic hydrolysis where solutions of sulfuric and hydrochloric acids were added to the tablets, and by catalytic hydrolysis where water was added tablets of solid-state NaBH4/Co composite. In acidic solutions hydrogen evolution occurred instantaneously, and at high concentrations of acids the releasing hydrogen contained an admixture of diborane. Hydrogen evolution from the solidstate NaBH4/Co composite proceeded at a uniform rate of 13.8±0.1 cm3·min-1, water vapor being the only impurity in the evolving gas.

scholarly journals Synthesis, Characterisation and In Vitro Anticancer Activity of Catalytically Active Indole-Based Half-Sandwich Complexes

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4540
Author(s):  
Joan J. Soldevila-Barreda ◽  
Kehinde B. Fawibe ◽  
Maria Azmanova ◽  
Laia Rafols ◽  
Anaïs Pitto-Barry ◽  
...  
Keyword(s):  
Sodium Formate ◽  
In Vitro Cytotoxicity ◽  
High Turnover ◽  
Normal Prostate ◽  
Prostate Cell ◽  
Ovarian Cancer Cell Lines ◽  
Catalytically Active ◽  
Half Sandwich ◽  
In Cells

The synthesis, characterisation and evaluation of the in vitro cytotoxicity of four indole-based half-sandwich metal complexes towards two ovarian cancer cell lines (A2780 and A2780cisR) and one normal prostate cell line (PNT2) are presented herein. Although capable of inducing catalytic oxidation of NADH and able to reduce NAD+ with high turnover frequencies, in cells and in the presence of sodium formate, these complexes also strongly interact with biomolecules such as glutathione. This work highlights that efficient out-of-cells catalytic activity might lead to higher reactivity towards biomolecules, thus inhibiting the in-cells catalytic processes.

Inactivation of Salmonella during Drying and Storage of Apple Slices Treated with Acidic or Sodium Metabisulfite Solutions

2003 ◽  
Vol 66 (12) ◽  
pp. 2245-2251 ◽  
Author(s):  
PATRICIA A. DiPERSIO ◽  
PATRICIA A. KENDALL ◽  
MEHMET CALICIOGLU ◽  
JOHN N. SOFOS
Keyword(s):  
Ascorbic Acid ◽  
Citric Acid ◽  
Acid Solution ◽  
Brilliant Green ◽  
Sodium Metabisulfite ◽  
Sterile Water ◽  
Citric Acid Solution ◽  
Acidic Solutions ◽  
Apple Slices ◽  
And Storage

This study was undertaken to determine whether pretreating inoculated Gala apple slices with metabisulfite or acidic solutions enhanced the inactivation of Salmonella during dehydration and storage. Apple slices inoculated with a five-strain mixture of Salmonella (7.6 log CFU/g) were pretreated, dried for 6 h at 60°C, and stored aerobically at 25°C for 28 days. Predrying treatments included (i) no treatment, (ii) 10 min of immersion in sterile water, (iii) 10 min of immersion in a 4.18% sodium metabisulfite solution, (iv) 10 min of immersion in a 3.40% ascorbic acid solution, and (v) 10 min of immersion in a 0.21% citric acid solution. Samples were plated on tryptic soy agar with 0.1% pyruvate (TSAP), brilliant green sulfa (BGS) agar, and xylose lysine tergitol 4 (XLT4) agar for the enumeration of bacteria. Populations were not significantly (P > 0.05) reduced by immersion in water but were reduced by 0.7 to 1.1 log CFU/g by immersion in acidic solutions. Immersion in the sodium metabisulfite solution reduced populations by 0.4, 1.3, and 5.4 log CFU/g on TSAP, BGS agar, and XLT4 agar, respectively. After 6 h of dehydration at 60°C, populations on untreated and water-treated slices were reduced by 2.7 to 2.8, 2.7 to 2.9, and 4.0 to 4.2 log CFU/g as determined with TSAP, BGS agar, and XLT4 agar, respectively. In contrast, populations on slices treated with sodium metabisulfite, ascorbic acid, and citric acid were reduced after 6 h of dehydration by 4.3, 5.2, and 3.8 log CFU/g, respectively, as determined with TSAP; by 4.7, 5.5, and 3.9 log CFU/g, respectively, as determined with BGS agar; and by 5.5, 5.7, and 5.6 log CFU/g, respectively, as determined with XLT4 agar. Bacteria were still detectable by direct plating after 28 days except on slices treated with ascorbic acid. Immersion in metabisulfite or acidic solutions prior to dehydration should enhance the inactivation of Salmonella during the dehydration and storage of Gala apple slices.

Use of Constant Temperature and Sodium Borohydride in the Trihydroxyindole Method for Catecholamines

1966 ◽  
Vol 12 (10) ◽  
pp. 659-669 ◽  
Author(s):  
Elizabeth Carlsen Gerst ◽  
Odd S Steinsland ◽  
William W Walcott
Keyword(s):  
Ascorbic Acid ◽  
Constant Temperature ◽  
Sodium Borohydride ◽  
Small Temperature ◽  
Temperature Variations ◽  
Stabilizing Agent ◽  
Fluorescent Analysis

Abstract Small temperature variations during fluorescent analysis with the trihydroxyindole method can introduce significant errors in the measurement of 15µg./L. or less of epinephrine or norepinephrine. To minimize temperature differences, we have devised a simple, constant-temperature system for the Farrand fluorometer. Decomposition of ascorbic acid prior to and during analysis also must be prevented. Sodium borchydride was found to be an effective stabilizing agent that contributes negligible fluorescence.These modifications minimize or eliminate much of the difficulty previously encountered in the use of the trihydroxyindole method.

Synthesis of gold nanoparticles in an interdigital micromixer using ascorbic acid and sodium borohydride as reducers

2011 ◽  
Vol 171 (1) ◽  
pp. 279-290 ◽  
Author(s):  
M. Luty-Błocho ◽  
K. Fitzner ◽  
V. Hessel ◽  
P. Löb ◽  
M. Maskos ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Sodium Borohydride
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