Mesoporous CoO-supported palladium nanocatalysts with high performance for o-xylene combustion

2018 ◽  
Vol 8 (3) ◽  
pp. 806-816 ◽  
Author(s):  
Shaohua Xie ◽  
Yuxi Liu ◽  
Jiguang Deng ◽  
Jun Yang ◽  
Xingtian Zhao ◽  
...  
Keyword(s):  
High Performance ◽  
Catalytic Combustion ◽  
Active Oxygen Species ◽  
Catalytic Performance ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Highly Active ◽  
Palladium Nanocatalysts ◽  
Supported Palladium

The adsorbed o-xylene species can immediately react with active oxygen species at the highly active Pd–CoO interface between Pd NPs and meso-CoO, thus resulting in good catalytic performance of Pd/meso-CoO for o-xylene catalytic combustion.

scholarly journals The effect of CuO modification for a TiO2 nanotube confined CeO2 catalyst on the catalytic combustion of butane

2018 ◽  
Vol 16 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Guansheng Yao ◽  
Liangpeng Wu ◽  
Tai Lv ◽  
Juan Li ◽  
Yanqin Huang ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Catalytic Combustion ◽  
Active Component ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Butane Oxidation ◽  
Oxygen Species ◽  
Xps Analysis ◽  
Exterior Surface ◽  
And Migration

AbstractA modified confined catalyst with CeO2 on the interior and CuO on the exterior surface of TiO2 nanotubes (Ce-in-TNT-Cu-out) was prepared and investigated for the combustion of butane catalytically. Compared with the Ce-in-TNT and TNT-Cu-out, the Ce-in-TNT-Cu-out presents a higher activity for butane oxidation, with a conversion of 10% at 200°C and a conversion of 90%) at 300°C. XPS analysis indicates that more Ce(IV) and Cu(I) components exist in the Ce-in-TNT-Cu-out catalyst. It is proposed that electron transfer ability between encapsulated CeO2 and loaded CuO is significantly enhanced by the confinement effect of the TiO2 nanotubes, facilitating the formation and migration of active oxygen species in the catalyst. This result shows that modulating the electronic property of the active component can further improve the catalytic combustion performance of the confined catalysts.

Synthesis and oxidation catalysis of a Ti-substituted phosphotungstate, and identification of the active oxygen species

2015 ◽  
Vol 5 (10) ◽  
pp. 4778-4789 ◽  
Author(s):  
Eri Takahashi ◽  
Keigo Kamata ◽  
Yuji Kikukawa ◽  
Sota Sato ◽  
Kosuke Suzuki ◽  
...  
Keyword(s):  
Active Oxygen Species ◽  
Catalytic Performance ◽  
Active Species ◽  
Active Oxygen ◽  
Oxidation Catalysis ◽  
Oxygen Species ◽  
Oxidation Reactions ◽  
Catalytically Active

A Ti-substituted phosphotungstate (I) showed high catalytic performance for several oxidation reactions. The truly catalytically active species was successfully isolated, and its anion structure was determined.

Promoting effects of MgO, (NH4)2SO4or MoO3modification in oxidative esterification of methacrolein over Au/Ce0.6Zr0.4O2-based catalysts

2016 ◽  
Vol 6 (14) ◽  
pp. 5453-5463 ◽  
Author(s):  
Yuchao Li ◽  
Lei Wang ◽  
Ruiyi Yan ◽  
Junxing Han ◽  
Suojiang Zhang
Keyword(s):  
Low Temperature ◽  
Significant Role ◽  
Active Oxygen Species ◽  
Catalytic Performance ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Oxidative Esterification ◽  
Temperature Reduction ◽  
Low Temperature Reduction

The MgO, (NH4)2SO4or MoO3-modified Au/Ce0.6Zr0.4O2catalysts presented better catalytic performance in the oxidative esterification of MAL to MMA and the active oxygen species assigned to low-temperature reduction played a significant role.

scholarly journals CHANGES OF SOME ANTIOXIDANT ENZYME ACTIVITIES IN LEAVES OF DROUGHT TOLERANT VARIETIES OF WHEAT FROM OLTENIA DURING VEGETATION STAGES

2008 ◽  
Vol 65 (1) ◽  
Author(s):  
Cristina Babeanu ◽  
Gabriela Paunescu ◽  
Daniela Popa ◽  
Alina Andrea Badita
Keyword(s):  
Crop Production ◽  
High Performance ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Antioxidant Enzyme Activities ◽  
Enzymatic Antioxidants ◽  
Oxygen Species ◽  
Cytotoxic Effects ◽  
Environmental Constraint ◽  
Drought Tolerant

In Oltenia drought is becoming a major environmental constraint on crop production and one of the solicited characteristics in the present in these area is drought tolerance. With that end in view, this study aims to thoroughly experiment of investigated varieties in comparative crops in the specific pedological, climatic and technological conditions of Oltenia in order to point out the most stable and high performance genotypes. One of the earliest responses of plants to drought is the accumulation of active oxygen species such as superoxide, hydroxyl radicals, hydrogen peroxide and singlet oxygenes. Plants protect cell systems from the cytotoxic effects of these active radicals using enzymes such as superoxide dismutase, ascorbat peroxidase, glutathione reductase, catalase and non-enzymatic antioxidants: glutathione, ascorbic acid and carotenoids. The current paper presents the changes of anti-oxidative indices in leaves of five varieties of wheat during development time. We observed significant differences between behaviors from different genotypes.

Characterization and functional properties of new everbearing strawberry (Fragaria x ananasa Duch.) cultivar, ‘Summertiara’ berries

2014 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Takeshi Nagai ◽  
Misuzu Tamai ◽  
Masato Sato ◽  
Yasuhiro Tanoue ◽  
Norihisa Kai ◽  
...  
Keyword(s):  
Vitamin C ◽  
Sensory Evaluation ◽  
Functional Properties ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Antihypertensive Activity ◽  
Oxygen Species ◽  
Total Anthocyanins ◽  
Strawberry Cultivar ◽  
The Stability

Background: In recent years, a new everbearing strawberry cultivar, ‘Summertiara’ was cultivated to supply the strawberries in pre-harvest season from July to October in Japan. For highly research and development of processing of this cultivar, ‘Summertiara’ berries, the objective of this study was to characterize these berries, with relation to chemical parameters, total phenols, total flavonoids, total vitamin C, and total anthocyanins, and was to investigate the solubility and the stability of anthocyanins from the berries. Moreover, the functional properties such as antioxidative activity, active oxygen species scavenging activity, and antihypertensive activity were also evaluated.Methods: Chemical analysis, colour measurement, and sensory evaluation of new everbearing strawberry cultivar, ‘Summertiara’ berries were performed. Next, the solubility of anthocyanins from the berries and stability of these against pH, temperature, and an incandescent lighting were investigated. Moreover, functional properties of the extracts prepared from berries were elucidated using 5 different methods.Results: The contents of water, proteins, lipids, carbohydrates, and ash were the same as those of other cultivar berries. The sugar-acid ratio in the berries was low; these were acidulous. By sensory evaluation, the main factors were vivid red colour, aroma, and acidity. The berries were rich in phenols, flavonoids, vitamin C, and anthocyanins. The anthocyanins of the berries became unstable by heat treatment and light exposures such as visible rays. On the other hand, the extracts prepared from the berries showed the functionalities such as antioxidant activity, active oxygen species scavenging activities, and antihypertensive activity.  Conclusions: The strawberry cultivar, ‘Summertiara’ berries were the most suitable for processing ingredient of strawberry-derived products with superior health promoting functionalities.Keywords: Summertiara, everbearing strawberry cultivar, characterization, sensory evaluation, color and storage, functional property

scholarly journals Ambient base-free glycerol oxidation over bimetallic PdFe/SiO2 by in situ generated active oxygen species

2021 ◽  
Author(s):  
Ricci Underhill ◽  
Mark Douthwaite ◽  
Richard J. Lewis ◽  
Peter J. Miedziak ◽  
Robert D. Armstrong ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Bimetallic Catalyst ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Active Oxygen Species ◽  
Catalytic Performance ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Paramagnetic Resonance ◽  
Temperature Oxidation

AbstractLow temperature oxidation of alcohols over heterogeneous catalysts is exceptionally challenging, particularly under neutral conditions. Herein, we report on an efficient, base-free method to oxidise glycerol over a 0.5%Pd-0.5%Fe/SiO2 catalyst at ambient temperature in the presence of gaseous H2 and O2. The exceptional catalytic performance was attributed to the in situ formation of highly reactive surface-bound oxygenated species, which promote the dehydrogenation on the alcohol. The PdFe bimetallic catalyst was determined to be significantly more active than corresponding monometallic analogues, highlighting the important role both metals have in this oxidative transformation. Fe leaching was confirmed to occur over the course of the reaction but sequestering experiments, involving the addition of bare carbon to the reactions, confirmed that the reaction was predominantly heterogeneous in nature. Investigations with electron paramagnetic resonance spectroscopy suggested that the reactivity in the early stages was mediated by surface-bound reactive oxygen species; no homogeneous radical species were observed in solution. This theory was further evidenced by a direct H2O2 synthesis study, which confirmed that the presence of Fe in the bimetallic catalyst neither improved the synthesis of H2O2 nor promoted its decomposition over the PdFe/SiO2 catalyst.

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