نتایج جستجو برای: silver catalyst

تعداد نتایج: 89016  

2016
Meilin Tao Dan Zhang Hongyu Guan Guohui Huang Xiaohong Wang

Production of lactic acid from glycerol is a cascade catalytic procedure using multifunctional catalysts combined with oxidative and acidic catalytic sites. Therefore, a series of silver-exchanged phosphomolybdic acid catalysts (AgxH3-xPMo12O40, x = 1 ~ 3, abbreviated as AgxPMo) was designed and applied in glycerol oxidation with O2 as an oxidant to produce lactic acid (LA) without adding any b...

Journal: :The Journal of organic chemistry 2016
Salaheddin A I Sharif Ewen D D Calder Alexander H Harkiss Marie Maduro Andrew Sutherland

A four-step synthesis of allylic trichloroacetimidates bearing a 2-proparyloxyaryl group has been developed from readily available 2-hydroxybenzaldehydes, and these have been used for the preparation of allylic amide derived 2H-chromenes using an Overman rearrangement and a 6-endo-dig hydroarylation. High yields of the 2H-chromenes were achieved using a stepwise approach involving an Overman re...

2011
F. Ghanbary A. Jafarian

This paper presents a study on the preparation method for Ag-TiO2 nano particles. Photodeposition of silver on TiO2 nanoparticles was carried out by adding a desired volume of aqueous AgNO3. Ag-deposited TiO2 catalyst was characterised by XRD, TEM, SEM. The Ag-TiO2 catalyst was evaluated for their photocatalytic activity towards the degradation of Malachite green (MG) under UV irradiation. An a...

2003
L. LEFFERTS

The interaction of N20 with pure silver at temperatures up to 900°C has been studied using temperature-programmed reduction and desorption; the interaction is compared with that of oxygen with silver. The effect of addition of NZO, as well as of the complete replacement of oxygen by NzO, on the oxidative dehydrogenation of methanol on a silver catalyst has also been studied. It was found that t...

2006
M. Bron D. Teschner A. Knop-Gericke B. Steinhauer A. Scheybal M. Hävecker D. Wang R. Födisch D. Hönicke A. Wootsch R. Schlögl P. Claus

The gas phase hydrogenation of acrolein over silver has been studied in a broad pressure range from ~2 mbar to 20 bar and with various silver materials (single crystals, sputtered silver, silica supported Ag nanoparticles) in an attempt to examine the question of "pressure and materials gap" in catalysis. High pressures as well as nanoparticles favour the formation of allyl alcohol (selectiviti...

2003
Zhijiang Li Maria Flytzani-Stephanopoulos

A new catalyst comprising cerium and silver ion-exchanged ZSM-5 zeolite is reported in this paper, for the reduction of nitric oxide by methane in the presence of excess oxygen. The bi-cation exchanged Ce-Ag-ZSM-5 catalyst was very active for this reaction, while either Ce-ZSM-5 or Ag-ZSM-5 alone showed low activity. The presence of oxygen in the feed gas mixture enhanced the activity of the ca...

2000
L. LEFFERTS J. G. van OMMEN

The interaction of an unsupported silver catalyst which had been pretreated by hydrogen at various temperatures with oxygen at 210°C has been studied using Temperature Programmed Reduction (TPR) over a temperature range up to 900°C. Hydrogen treatment at 500°C or above before the oxidation step causes the formation of extra species, thought to be OH groups in the sub-surface of the sample. A pe...

Journal: :Colloids and surfaces. B, Biointerfaces 2014
Patricia Fernanda Andrade Andreia Fonseca de Faria Douglas Soares da Silva Juliano Alves Bonacin Maria do Carmo Gonçalves

This paper describes the synthesis of silver nanoparticles using an aqueous silver nitrate solution in the presence of glucose as a reducing agent, sodium hydroxide as a reaction catalyst and β-CD as a stabilizer. The structure and the morphology associated to the stabilizing layer around the silver nanoparticles were investigated. Raman spectroscopy confirmed the nanoparticle surface modificat...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2006
Masayuki Itagaki Yasuhiro Fujimura Isao Shitanda Kunihiro Watanabe Toshinori Hachiya

The channel flow double electrode (CFDE) was used for the evaluation of the oxygen reduction activities in alkaline solution of rare-earth oxide-supported silver catalysts. The CFDE cell was modified for the experiment using the powder catalyst as a working electrode. In the present experiment, the silver electrode was supported with CeO2 in order to improve the performance of the oxygen reduct...

1999
Israel E. Wachs

In situ Raman spectroscopy is rapidly becoming a very popular catalyst characterization method because Raman cells are being designed that can combine in situ molecular characterization studies with simultaneous fundamental quantitative kinetic studies. The dynamic nature of catalyst surfaces requires that both sets of information be obtained for a complete fundamental understanding of catalyti...

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