The effects of the nature of TiO2 supports on the catalytic performance of Rh–Mn/TiO2 catalysts in the synthesis of C2 oxygenates from syngas

2019 ◽  
Vol 9 (14) ◽  
pp. 3675-3685 ◽  
Author(s):  
Jun Yu ◽  
Jihang Yu ◽  
Zhangping Shi ◽  
Qiangsheng Guo ◽  
Xiuzhen Xiao ◽  
...  
Keyword(s):  
Phase Composition ◽  
Crystalline Phase ◽  
Catalytic Properties ◽  
Catalytic Performance

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.

scholarly journals Influence of the Reduction Temperature and the Nature of the Support on the Performance of Zirconia and Alumina-Supported Pt Catalysts for n-Dodecane Hydroisomerization

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Diana García-Pérez ◽  
Maria Consuelo Alvarez-Galvan ◽  
Jose M. Campos-Martin ◽  
Jose L. G. Fierro
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Major Influence ◽  
Pt Catalysts ◽  
Reduction Temperature ◽  
Metal Dispersion ◽  
Tungsten Oxides ◽  
Supported Pt Catalysts

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.

PtPd nanoframes derived from Pd@PdPt core–shell rhombic dodecahedrals with excellent catalytic performance toward methanol oxidation

2021 ◽  
Author(s):  
Yangyang Ren ◽  
Chuanliang Li ◽  
Baosong Li ◽  
Fan Gao ◽  
Xinghua Zhang ◽  
...  
Keyword(s):  
Methanol Oxidation ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Core Shell ◽  
Acid Environment ◽  
Excellent Catalytic Performance

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

Influence of Pressure on the Crystallization in SiO2f/SiO2 Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1236-1238
Author(s):  
Chang Ming Xu ◽  
Shi Wei Wang ◽  
Xiao Xian Huang ◽  
Jing Kun Guo
Keyword(s):  
Phase Composition ◽  
Crystalline Phase ◽  
Hot Pressing ◽  
Crystallization Behavior ◽  
Nucleation Mechanism ◽  
Composition Analysis ◽  
Pressing Pressure ◽  
Surface Nucleation ◽  
Bulk Nucleation ◽  
Phase Composition Analysis

The influence of pressure on the crystallization behavior in SiO2f/SiO2 composites hotpressed at 1350°C was studied. The crystalline phase composition analysis on SiO2f/SiO2 composites revealed that the formation of cristobalite was promoted when the hot-pressing pressure ≤ 12 MPa, however suppressed with higher pressure applied. It can be ascribed to the nucleation mechanism change from surface nucleation to bulk nucleation. Analysis on relative density as well as fracture microstructure of SiO2f/SiO2 composites confirmed the conclusion.

Effect of Ions Substitution on Nanospace La-Fe-O Catalytic Properties for Simultaneous Removal of NOx and Soot

2013 ◽  
Vol 740 ◽  
pp. 565-569
Author(s):  
Xiao Xiao Meng ◽  
Mao Xiang Jing ◽  
Feng Lin He ◽  
Xiang Qian Shen
Keyword(s):  
High Performance ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Dip Coating ◽  
Exhaust Emission ◽  
Simultaneous Removal ◽  
Microstructural Characteristics ◽  
Coating Method ◽  
Citrate Gel Process ◽  
Dip Coating Method

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%).

Particle anisotropy and crystalline phase transition in one-pot synthesis of nano-zirconia: a causal relationship

CrystEngComm ◽  
2018 ◽  
Vol 20 (7) ◽  
pp. 879-888 ◽  
Author(s):  
Francesca Tana ◽  
Andrea Serafini ◽  
Luca Lutterotti ◽  
Alberto Cigada ◽  
Fabio Variola ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Composition ◽  
Causal Relationship ◽  
Crystalline Phase ◽  
One Pot ◽  
One Pot Synthesis ◽  
Nanocrystal Growth ◽  
Particle Anisotropy ◽  
Morphological Transformations ◽  
Crystalline Phase Transition

The effects of experimental variables on zirconia nanocrystal growth are investigated, correlating the morphological transformations with phase composition in synthesized nanopowders.

scholarly journals Directed Evolution of a Homodimeric Laccase from Cerrena unicolor BBP6 by Random Mutagenesis and In Vivo Assembly

2018 ◽  
Vol 19 (10) ◽  
pp. 2989 ◽  
Author(s):  
Ji Zhang ◽  
Fuying Ma ◽  
Xiaoyu Zhang ◽  
Anli Geng
Keyword(s):  
Directed Evolution ◽  
Laccase Activity ◽  
Catalytic Properties ◽  
Random Mutagenesis ◽  
Catalytic Performance ◽  
Industrial Applications ◽  
Subunit Interaction ◽  
Cerrena Unicolor ◽  
Protein Model

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.

Catalytic Properties of Ni/CNTs and Ca-Promoted Ni/CNTs for Methanation Reaction of Carbon Dioxide

2014 ◽  
Vol 924 ◽  
pp. 217-226 ◽  
Author(s):  
Xiang Feng Hu ◽  
Wen Yang ◽  
Ning Wang ◽  
Shi Zhong Luo ◽  
Wei Chu
Keyword(s):  
Carbon Dioxide ◽  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Catalytic Properties ◽  
Supported Catalyst ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Methanation Reaction ◽  
Ni Species ◽  
Nickel Species

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.

Phase composition, physicochemical and catalytic properties of cobalt–aluminum–zeolite systems

2015 ◽  
Vol 64 (10) ◽  
pp. 2371-2376 ◽  
Author(s):  
E. Yu. Asalieva ◽  
L. V. Sineva ◽  
E. A. Zhukova ◽  
V. Z. Mordkovich ◽  
B. M. Bulychev
Keyword(s):  
Phase Composition ◽  
Catalytic Properties
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