scholarly journals Niobium oxide prepared through a novel supercritical-CO2-assisted method as a highly active heterogeneous catalyst for the synthesis of azoxybenzene from aniline

2019 ◽  
Vol 21 (21) ◽  
pp. 5852-5864 ◽  
Author(s):  
Yehan Tao ◽  
Bhawan Singh ◽  
Vanshika Jindal ◽  
Zhenchen Tang ◽  
Paolo P. Pescarmona

High-surface area Nb2O5 nanoparticles synthesised by a novel supercritical-CO2-assisted method displayed extremely high activity as heterogeneous catalyst in the oxidative coupling of aniline to azoxybenzene using the green oxidant H2O2.

2016 ◽  
Vol 4 (43) ◽  
pp. 17129-17137 ◽  
Author(s):  
Sanpei Zhang ◽  
Zhaoyin Wen ◽  
Yang Lu ◽  
Xiangwei Wu ◽  
Jianhua Yang

We demonstrate a low-cost and facile strategy to synthesize mixed-valent MnOxspheres constructed from nanocrystals (~5 nm), containing MnII, MnIII, and MnIVspecies. Such highly active mixed-valent MnOxspheres with high surface area greatly improve the performance of Li–O2batteries.


RSC Advances ◽  
2020 ◽  
Vol 10 (50) ◽  
pp. 30214-30222
Author(s):  
Bolong Jiang ◽  
Jiaojing Zhang ◽  
Yanguang Chen ◽  
Hua Song ◽  
Tianzhen Hao ◽  
...  

Co3O4/MCM-41 adsorbent with high surface area and more active sites was successfully prepared by ultrasonic assisted impregnation (UAI) technology and it has been found that the sulfur capacity was improved by 33.2% because of ultrasonication.


Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 8
Author(s):  
Emmanuel O. Ogunsona ◽  
Koffi L. Dagnon ◽  
Nandika Anne D'Souza

Developing an environmentally benign styrene foam is a critical environmental need. Supercritical CO2 use in foams has proven to be a valuable path. Adding fillers to increase bubble nucleation has been pursued concurrently. A prominent filler used is high surface area fillers, such as smectic clays. However, all studies to date show a limit of 152% in compressive moduli and 260% in the compressive stress. The values, even with such gains, limit structural application. A seminal work in 1987 by Suh and Cotton proved that carbonyl linkages in calcium carbonates and CO2 interact and impact nucleation efficiency and performance in supercritical CO2 foams. In this paper, a high surface area clay (layer double hydroxides) which begins in an exfoliated state, then functionalized with a long chain alkyl carboxylate (stearic acid) is synthesized. The result is a remarkable multi-fold improvement to the compressive properties in comparison to polystyrene (PS); a 268% and 512% increase in compressive modulus and strength, respectively. Using a pre-delaminated approach, the higher surface area was achieved in the clays. The presence of the stearate improved the interactions between the clay galleries and PS through hydrophobic-hydrophobic interactions. The glass transition temperature of the nanocomposites was observed to shift to higher values after foaming. The results point to a new path to increase performance using a pre-delaminated clay with functional groups for environmentally benign foams.


2020 ◽  
Vol 56 (14) ◽  
pp. 2095-2098 ◽  
Author(s):  
Eri Hayashi ◽  
Yui Yamaguchi ◽  
Yusuke Kita ◽  
Keigo Kamata ◽  
Michikazu Hara

High-surface-area β-MnO2 nanoparticles exhibited high activity for the one-pot oxidative sulfonamidation of thiols to sulfonamides using O2 and NH3.


2020 ◽  
Vol 12 (42) ◽  
pp. 47389-47396 ◽  
Author(s):  
Dinithi Rathnayake ◽  
Inosh Perera ◽  
Alireza Shirazi-Amin ◽  
Peter Kerns ◽  
Shanka Dissanayake ◽  
...  

2015 ◽  
Vol 5 (4) ◽  
pp. 2300-2304 ◽  
Author(s):  
Gang Feng ◽  
Ping Chen ◽  
Hui Lou

Supported palladium catalysts on carbon-nitrogen composites with high surface area are highly active for aqueous-phase hydrogenation of phenol.


2016 ◽  
Vol 36 (1) ◽  
pp. 1-41 ◽  
Author(s):  
Nurhidayatullaili Muhd Julkapli ◽  
Samira Bagheri

AbstractResearchers normally consider MgO as a promising high-surface-area heterogeneous catalyst support, additive, and promoter for many kinds of chemical reactions due to its certain properties, including stoichiometry and composition, cation valence, redox properties, acid-base character, and crystal and electronic structure. The presence of MgO as a support catalyst also modifies the electronic state of the overall catalytic performance by electron transfer between the native catalyst and MgO as support. The influence is clarified by alteration of acid-base properties of the catalyst-supported MgO. Meanwhile, the method, chemical composition, and condition in the preparation of MgO are the important factors affecting its surface and catalytic properties. Therefore, MgO with a high surface area and nanocrystalline structure has encouraging applications for some reactions, including as dry reforming, dehydrohalogenation, oxidative dehydrogenation of butane, nonoxidative dehydrogenation of ethylbenzene, decomposition of CCl


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