Oxidative Reforming of Methane over Rh-Containing Zeolites: Active Species and Role of Zeolite Framework

2021 ◽  
Author(s):  
Ryota Osuga ◽  
Shuhei Yasuda ◽  
Masato Sawada ◽  
Ryo Manabe ◽  
Hisashi Shima ◽  
...  
Keyword(s):  
Active Species ◽  
Zeolite Framework ◽  
Oxidative Reforming

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

The Effects of Preparation Methods on Iron Structures of Iron-Supported HZSM-5 and their Catalytic Performance for Methanol Dehydration

2016 ◽  
Vol 723 ◽  
pp. 633-639
Author(s):  
Waenkaew Pantupho ◽  
Arthit Neramittagapong ◽  
Nuttawut Osakoo ◽  
Jatuporn Wittayakun ◽  
Sirinuch Loiha
Keyword(s):  
Flow Reactor ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Active Species ◽  
Iron Complex ◽  
Methanol Dehydration ◽  
Low Carbon ◽  
Zeolite Framework ◽  
Preparation Methods ◽  
Binuclear Iron

Iron-supported HZSM-5 catalysts were prepared by hydrothermal (Fe-HZSM-5_HYD) and impregnation methods (Fe/HZSM-5_IMP). The active species of binuclear-iron complex and iron-substituted zeolite framework, confirmed by EXAFS analysis, were observed on Fe/HZSM-5_IMP and Fe-HZSM-5_HYD, respectively. The catalysts were used for production of dimethyl ether (DME) by methanol dehydration at 200-350 °C using fixed bed flow reactor. Fe/HZSM-5_IMP showed higher catalytic conversion than Fe-HZSM-5_HYD. However, the Fe/HZSM-5_IMP catalyst was less selective to DME product and strongly deactivated for 24h. The deactivation might due to transformation of binuclear-iron to the a-iron site which was strong acidic strengh. The iron-substituted zeolite framework of Fe-HZSM-5_HYD showed high stability toward methanol dehydration. Moreover, the catalyst showed advantages of good selective to DME and low carbon deposition on surface. These results suggested that the iron-substituted zeolite framework structure could improve catalytic performance for mrthanol dehydration.

In situ synthesis of hierarchical nitrogen-doped MoS2 microsphere with an excellent visible light-driven photocatalytic nitrogen fixation ability

2020 ◽  
Vol 13 (05) ◽  
pp. 2051031
Author(s):  
Abulikemu Abulizi ◽  
Hujiabudula Maimaitizi ◽  
Dilinuer Talifu ◽  
Yalkunjan Tursun
Keyword(s):  
Visible Light ◽  
High Performance ◽  
Nucleation Site ◽  
Active Species ◽  
Nitrogen Doped ◽  
Photogenerated Electrons ◽  
The Hierarchical Structure ◽  
Visible Light Driven

A photocatalyst of high-performance hierarchical nitrogen-doped MoS2 (N-MoS2) microsphere was fabricated by an in situ hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB). The as-prepared N-MoS2 microsphere was self-assembled by extremely thin interleaving petals, where CTAB acts as a nucleation site for the formation of the interleaving petals due to the strong interaction between CTA+ and [Formula: see text]. N-MoS2 showed higher N2 fixation ability (101.2 [Formula: see text] mol/g(cat)h) than the non-doped MoS2 under the visible light irradiation, and the improved photocatalytic activity could be ascribed to that the doped N narrows the band gap, and the surface reflecting and scattering effect caused by the hierarchical structure enhance the light adsorption. The trapping experiment of active species was also investigated to evaluate the role of photogenerated electrons in the photocatalytic reaction process. Meanwhile, the possible mechanism for the formation and excellent photocatalytic performance of N-MoS2 microsphere were also presented.

scholarly journals Fabrication of MgFe2O4-ZnO Nanocomposites for Photocatalysis of Organic Pollutants under Solar Light Radiation

2019 ◽  
Vol 31 (12) ◽  
pp. 2995-3003
Author(s):  
Krushitha Shetty ◽  
B.S. Prathibha ◽  
Dinesh Rangappa ◽  
K.S. Anatharaju ◽  
H.P. Nagaswarupa ◽  
...  
Keyword(s):  
Band Gap ◽  
Active Species ◽  
Solution Combustion ◽  
Quantization Effect ◽  
Photocatalytic Activities ◽  
Efficient Charge ◽  
Temperature Solution ◽  
Uv Visible ◽  
Photocatalytic Applications

MgFe2O4, ZnO and MgFe2O4-ZnO samples were successfully prepared through low temperature solution combustion route. The structural and morphological investigation were accomplished by PXRD, HRSEM, UV-visible and FTIR. The PXRD results point towards the reduced size of synthesized nanocomposites, which was further confirmed by HRSEM studies. Optical properties of the prepared samples were examined by UV-visible spectroscopy. The band gap seems to be widened for prepared nanocomposites compared to pure MgFe2O4. The photocatalytic degradation of methylene blue under sunlight was superior in contrast to pure MgFe2O4 and ZnO. MgFe2O4-ZnO (1:1) acts as the most effective photocatalyst activity compared to pure MgFe2O4 and ZnO. EIS data was proven to be an efficient tool for understanding the electronic properties for photocatalytic studies. The enhanced sunlight-driven photocatalytic activities of MgFe2O4-ZnO nanocomposite is supported by the factors such as quantization effect, band gap widening and efficient charge separation. MgFe2O4-ZnO showed excellent reusability with high photocatalytic efficiencies suggesting its suitability for solar photocatalytic applications. Additionally, scavenging test was conducted to know the role of all active species during photoelectrocatalysis. This work presents a facile and effective route for the construction of MgFe2O4-ZnO nanocomposites with intriguing structures and multiple functions.

scholarly journals Ubiquitin Extension Protein UEP1 Modulates Cell Death and Resistance to Various Pathogens in Tobacco

2019 ◽  
Vol 109 (7) ◽  
pp. 1257-1269
Author(s):  
You-Ping Xu ◽  
Yuan Zhao ◽  
Xiao-Yi Song ◽  
Yun-Feng Ye ◽  
Ren-Gang Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Disease Resistance ◽  
Ribosomal Protein ◽  
Mosaic Virus ◽  
Amine Oxidase ◽  
Active Species ◽  
26S Proteasome ◽  
Virus Induced Gene Silencing ◽  
Copper Amine Oxidase

Ubiquitin (Ub) extension proteins (UEPs) are fusion proteins of a Ub at the N terminus to a ribosomal protein. They are the main source of Ub and the only source of extension ribosomal protein. Although important roles of the Ub-26S proteasome system in various biological processes have been well established, direct evidence for the role of UEP genes in plant defense is rarely reported. In this study, we cloned a Ub-S27a-type UEP gene (NbUEP1) from Nicotiana benthamiana and demonstrated its function in cell death and disease resistance. Virus-induced gene silencing of NbUEP1 led to intensive cell death, culminating in whole-seedling withering. Transient RNA interference (RNAi) of NbUEP1 caused strong cell death in infiltrated areas, while stable NbUEP1-RNAi tobacco plants constitutively formed necrotic lesions in leaves. NbUEP1-RNAi plants exhibited increased resistance to the oomycete Pythium aphanidermatum and viruses Tobacco mosaic virus and Cucumber mosaic virus while displaying decreased resistance to the nematode Meloidogyne incognita compared with non-RNAi control plants. Transcription profiling analysis indicated that jasmonate and ethylene pathways, lipid metabolism, copper amine oxidase-mediated active species generation, glycine-rich proteins, vacuolar processing enzyme- and RD21-mediated cell death and defense regulation, and autophagy might be associated with NbUEP1-mediated cell death and resistance. Our results provided evidence for the important roles of plant UEPs in modulating plant cell death and disease resistance.

Liquid-Phase Hydrodechlorination of CCl4 to CHCl3 on Pd/Carbon Catalysts: Nature and Role of Pd Active Species

2002 ◽  
Vol 209 (2) ◽  
pp. 279-288 ◽  
Author(s):  
Luisa Ma. Gómez-Sainero ◽  
Xosé L. Seoane ◽  
José L.G. Fierro ◽  
Adolfo Arcoya
Keyword(s):  
Liquid Phase ◽  
Active Species ◽  
Carbon Catalysts

Towards the Synthesis of a Dewar Furan Stabilized by a Pinching Group: the Role of Dewar o-Xylylenes as Dienes and Dienophiles

1991 ◽  
Vol 44 (9) ◽  
pp. 1293 ◽  
Author(s):  
RN Warrener ◽  
IG Pitt ◽  
RA Russell
Keyword(s):  
Active Species ◽  
Diels Alder

The synthesis of a photosubstrate (42) suitable for the production of a Dewar furan (46) containing a four-carbon bridge at the 1,4-position is described. The route to this product illustrates an example of transfer technology in synthesis, by using the oxanorbornadiene (29). Other active species such as Dewar benzene (32) and Dewar o-xylylene (50) play key roles as intermediates. Diels-Alder cycloadditions are also central to the overall strategy, and some observations are made regarding the facial specificities operating, especially in regard to Dewar o-xylylene (50) and its dimerization. Attempts to isolate the photoproducts, presumably involving the Dewar furan (46) as intermediate, were unsuccessful.

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