Two scandium coordination polymers: rapid synthesis and catalytic properties

CrystEngComm ◽  
2019 ◽  
Vol 21 (35) ◽  
pp. 5261-5268 ◽  
Author(s):  
Ziqian Zhu ◽  
Yufang Tao ◽  
Yansong Jiang ◽  
Liying Zhang ◽  
Jianing Xu ◽  
...  

Two new scandium coordination polymers were synthesized by MW and hydrothermal methods, and exhibited good catalytic performance.

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Diana García-Pérez ◽  
Maria Consuelo Alvarez-Galvan ◽  
Jose M. Campos-Martin ◽  
Jose L. G. Fierro

Catalysts based on zirconia- and alumina-supported tungsten oxides (15 wt % W) with a small loading of platinum (0.3 wt % Pt) were selected to study the influence of the reduction temperature and the nature of the support on the hydroisomerization of n-dodecane. The reduction temperature has a major influence on metal dispersion, which impacts the catalytic activity. In addition, alumina and zirconia supports show different catalytic properties (mainly acid site strength and surface area), which play an important role in the conversion. The NH3-TPD profiles indicate that the acidity in alumina-based catalysts is clearly higher than that in their zirconia counterparts; this acidity can be attributed to a stronger interaction of the WOx species with alumina. The PtW/Al catalyst was found to exhibit the best catalytic performance for the hydroisomerization of n-dodecane based on its higher acidity, which was ascribed to its larger surface area relative to that of its zirconia counterparts. The selectivity for different hydrocarbons (C7–10, C11 and i-C12) was very similar for all the catalysts studied, with branched C12 hydrocarbons being the main products obtained (~80%). The temperature of 350 °C was clearly the best reduction temperature for all the catalysts studied in a trickled-bed-mode reactor.


Author(s):  
Yangyang Ren ◽  
Chuanliang Li ◽  
Baosong Li ◽  
Fan Gao ◽  
Xinghua Zhang ◽  
...  

PtPd nanoframes with excellent catalytic properties were obtained by etching Pd@PdPt core–shell RDs with Fe3+ in an acid environment.


2013 ◽  
Vol 740 ◽  
pp. 565-569
Author(s):  
Xiao Xiao Meng ◽  
Mao Xiang Jing ◽  
Feng Lin He ◽  
Xiang Qian Shen

The catalysts La0.8K0.2FeO3(LKFO), La0.8K0.2Fe0.7Mn0.3O3(LKFMO) and La0.8K0.2Fe0.67Mn0.3Pt0.03O3(LKFMPO) were prepared by the citrate-gel process and the catalyst-coated honeycomb ceramic devices were prepared by the citrate-gel assisted dip-coating method. All the catalysts have a high performance on the simultaneous removal of NOxand soot at a temperature range of 200 to 400°C under the practical diesel exhaust emission. The obvious catalytic improvement is largely due to the effects of ions substitution, pore structure and microstructural characteristics of the catalysts. The catalytic performance order is LKFMPO > LKFMO > LKFO. Among them the LKFMPO catalyst shows the best catalytic properties, especially in the removal of NOx, with a maximum conversion rate of NOx(21.2%).


2018 ◽  
Vol 19 (10) ◽  
pp. 2989 ◽  
Author(s):  
Ji Zhang ◽  
Fuying Ma ◽  
Xiaoyu Zhang ◽  
Anli Geng

Laccases have great potential for industrial applications due to their green catalytic properties and broad substrate specificities, and various studies have attempted to improve the catalytic performance of these enzymes. Here, to the best of our knowledge, we firstly report the directed evolution of a homodimeric laccase from Cerrena unicolor BBP6 fused with α-factor prepro-leader that was engineered through random mutagenesis followed by in vivo assembly in Saccharomyces cerevisiae. Three evolved fusion variants selected from ~3500 clones presented 31- to 37-fold increases in total laccase activity, with better thermostability and broader pH profiles. The evolved α-factor prepro-leader enhanced laccase expression levels by up to 2.4-fold. Protein model analysis of these variants reveals that the beneficial mutations have influences on protein pKa shift, subunit interaction, substrate entrance, and C-terminal function.


2014 ◽  
Vol 924 ◽  
pp. 217-226 ◽  
Author(s):  
Xiang Feng Hu ◽  
Wen Yang ◽  
Ning Wang ◽  
Shi Zhong Luo ◽  
Wei Chu

Nickel/carbon nanotubes (Ni/CNTs), Nickel/alumina (Ni/Al2O3), calcium-promoted Ni/CNTs and calcium-promoted Ni/Al2O3 were synthesized by impregnation method. Methanation of carbon dioxide was used as a probe to evaluate their catalytic performance. The features of these Ni-based catalysts were investigated via XRD, H2-TPR, H2-TPD and the N2 adsorptiondesorption isotherms. H2-TPR showed that nickel species on Ni/CNTs was reduced more easily with respect to that on Ni/Al2O3, and addition of Ca can increase the content of easily reducible Ni species for Ni/CNTs. XRD and H2-TPD indicated that addition of Ca promoted dispersion for CNTs-supported catalyst. These finding ultimately enhanced catalytic activity and stability for Ni/CNTs catalyst modified with Ca.


2019 ◽  
Vol 9 (14) ◽  
pp. 3675-3685 ◽  
Author(s):  
Jun Yu ◽  
Jihang Yu ◽  
Zhangping Shi ◽  
Qiangsheng Guo ◽  
Xiuzhen Xiao ◽  
...  

Four types of TiO2 with different rutile/anatase crystalline phase compositions were used as supports, and the effect of the TiO2 phase composition on the catalytic properties of supported Rh catalysts in the synthesis of C2 oxygenates from syngas was studied.


2016 ◽  
Vol 40 (3) ◽  
pp. 2315-2320 ◽  
Author(s):  
Li-Ping Mei ◽  
Rui Wang ◽  
Pei Song ◽  
Jiu-Ju Feng ◽  
Zhi-Gang Wang ◽  
...  

Bimetallic yolk–shell Ni@PtNi NC-rGO were facilely prepared by a one-pot solvothermal method, which exhibited enhanced catalytic performance for p-nitrophenol reduction.


2013 ◽  
Vol 15 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Barbara Litawa ◽  
Piotr Michorczyk ◽  
Jan Ogonowski

In this work the La2O3/CeO2 (33 mol % of La) and CaO/CeO2 (33 mol % of Ca) catalysts were prepared by the impregnation method and characterized by XRD and CO2-TPD. The catalytic properties of the catalysts were tested in the OCM process at 1073 K using the methane/oxygen mixture of the mole ratio 3.7 or 2.5 additionally containing CO2 and helium balance. It was found that in the presence of both catalysts an addition of CO2 enhances the selectivity to the ethylene and ethane and it does not have any negative influence on methane conversion. In the case of the CaO/CeO2 catalyst the promoting effect of CO2 was the highest. When the partial pressure of CO2 equals to 39 kPa the increase in selectivity from 36 to 41% was noted while the conversion of methane equal to 19.4-19.7 %.


2011 ◽  
Vol 37 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Cui-huan Jiao ◽  
Cui-hong He ◽  
Jian-chen Geng ◽  
Guang-hua Cui

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