scholarly journals Biosynthesis of au nanoparticles by a marine bacterium and enhancing their catalytic activity through metal ions and metal oxides

2018 ◽  
Vol 35 (2) ◽  
pp. e2727
Author(s):  
Haikun Zhang ◽  
Xiaoke Hu
Keyword(s):  
Catalytic Activity ◽  
Metal Ions ◽  
Metal Oxides ◽  
Marine Bacterium ◽  
Au Nanoparticles

In Situ Formation of Pt-Au Nanoparticles on Magnetic Composites Carriers: Tuning Catalytic Activity by Incorporation of Different Metal Oxides

2017 ◽  
Vol 39 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Zewu Zhang ◽  
Qiong Wu ◽  
Xiaohai Bu ◽  
Zusheng Hang ◽  
Zhangzhong Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metal Oxides ◽  
Au Nanoparticles ◽  
Magnetic Composites ◽  
In Situ Formation

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

The effect of partial exchange of sulphonated macroporous styrene-divinylbenzene copolymers for different ions on their catalytic activity

1981 ◽  
Vol 46 (10) ◽  
pp. 2354-2363 ◽  
Author(s):  
Svatomír Kmošták ◽  
Karel Setínek
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Metal Ions ◽  
Gas Phase ◽  
Transition Metal Ions ◽  
Exchange Capacity ◽  
Total Exchange Capacity ◽  
Styrene Divinylbenzene ◽  
Na Ions ◽  
Type Of Transition

The catalytic activity of sulphonated macroporous styrene-divinylbenzene copolymers, the exchange capacity of which was neutralized from 30, 50 and 80% by Fe(III) ions and from 30% by Na ions and that of Wofatit Y-37 ion exchanger neutralized from 10% of its total exchange capacity by several transition metal ions and by sodium has been studied in isomerisation of cyclohexene and dehydration of 1-propanol in the gas phase at 130 °C. It was demonstrated that in both reactions transition metal ions exhibit additional effect to the expected neutralization of the polymer acid groups. In the case of cyclohexene isomerization, this effect depends on the degree of crosslinking of polymer mass of the catalyst. Such dependence has not been, however, observed in dehydration of 1-propanol. The type of transition metal ions did not exhibit any significant effect on the catalytic activity of the polymer catalysts studied.

Probing the catalytic activity and heterogeneity of Au-nanoparticles at the single-molecule level

2009 ◽  
Vol 11 (15) ◽  
pp. 2767 ◽  
Author(s):  
Weilin Xu ◽  
Jason S. Kong ◽  
Peng Chen
Keyword(s):  
Catalytic Activity ◽  
Single Molecule ◽  
Au Nanoparticles ◽  
Single Molecule Level

Homogeneous dispersion of Au nanoparticles into mesoporous SBA-15 exhibiting improved catalytic activity for nitroaromatic reduction

2015 ◽  
Vol 202 ◽  
pp. 219-225 ◽  
Author(s):  
Shweta Sareen ◽  
Vishal Mutreja ◽  
Bonamali Pal ◽  
Satnam Singh
Keyword(s):  
Catalytic Activity ◽  
Au Nanoparticles ◽  
Homogeneous Dispersion

scholarly journals CO Oxidation over Metal Oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2) Doped CuO-Based Catalysts Supported on Mesoporous Ce0.8Zr0.2O2 with Intensified Low-Temperature Activity

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 724 ◽  
Author(s):  
Yan Cui ◽  
Leilei Xu ◽  
Mindong Chen ◽  
Chufei Lv ◽  
Xinbo Lian ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Co Oxidation ◽  
Active Sites ◽  
Earth Metal ◽  
High Dispersion ◽  
Impregnation Method ◽  
X Ray

CuO-based catalysts are usually used for CO oxidation owing to their low cost and excellent catalytic activities. In this study, a series of metal oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2)-doped CuO-based catalysts with mesoporous Ce0.8Zr0.2O2 support were simply prepared by the incipient impregnation method and used directly as catalysts for CO catalytic oxidation. These mesoporous catalysts were systematically characterized by X-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), and H2 temperature programmed reduction (H2-TPR). It was found that the CuO and the dopants were highly dispersed among the mesoporous framework via the incipient impregnation method, and the strong metal framework interaction had been formed. The effects of the types of the dopants and the loading amounts of the dopants on the low-temperature catalytic performances were carefully studied. It was concluded that doped transition metal oxides could regulate the oxygen mobility and reduction ability of catalysts, further improving the catalytic activity. It was also found that the high dispersion of rare earth metal oxides (PrO2, Sm2O3) was able to prevent the thermal sintering and aggregation of CuO-based catalysts during the process of calcination. In addition, their presence also evidently improved the reducibility and significantly reduced the particle size of the CuO active sites for CO oxidation. The results demonstrated that the 15CuO-3Fe2O3/M-Ce80Zr20 catalyst with 3 wt. % of Fe2O3 showed the best low-temperature catalytic activity toward CO oxidation. Overall, the present Fe2O3-doped CuO-based catalysts with mesoporous nanocrystalline Ce0.8Zr0.2O2 solid solution as support were considered a promising series of catalysts for low-temperature CO oxidation.

scholarly journals Stability profiles of transition metal oxides in the oxygen evolution reaction in alkaline medium

2019 ◽  
Vol 7 (45) ◽  
pp. 25865-25877 ◽  
Author(s):  
Aliki Moysiadou ◽  
Xile Hu
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Oxygen Evolution ◽  
Alkaline Medium ◽  
Transition Metal Oxides ◽  
Oxygen Evolution Reaction ◽  
Electrolyte Solutions ◽  
Compositional Changes ◽  
Dynamic Exchange

Metal oxides undergo compositional changes due to a dynamic exchange of metal ions with the electrolyte solutions during the oxygen evolution reaction.

Surface- and Structure-Dependent Catalytic Activity of Au Nanoparticles for Oxygen Reduction Reaction†

2010 ◽  
Vol 22 (3) ◽  
pp. 755-761 ◽  
Author(s):  
Youngmin Lee ◽  
Aviva Loew ◽  
Shouheng Sun
Keyword(s):  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Au Nanoparticles ◽  
Reduction Reaction
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