scholarly journals Au–Pd NPs immobilised on nanostructured ceria and titania: impact of support morphology on the catalytic activity for selective oxidation

2018 ◽  
Vol 8 (10) ◽  
pp. 2529-2539 ◽  
Author(s):  
Motaz Khawaji ◽  
David Chadwick
Keyword(s):  
Catalytic Activity ◽  
Selective Oxidation ◽  
Highly Active ◽  
Nanostructured Ceria

Au–Pd colloidal NPs immobilised on ceria nanorods are highly active catalysts for selective oxidation.

Deactivation of arenetitanium(II) bromoalane complexes in the cyclotrimerization of butadiene

1986 ◽  
Vol 51 (12) ◽  
pp. 2751-2759 ◽  
Author(s):  
Jindřich Poláček ◽  
Helena Antropiusová ◽  
Lidmila Petrusová ◽  
Karel Mach
Keyword(s):  
Catalytic Activity ◽  
Catalytic System ◽  
Model System ◽  
Highly Active ◽  
Catalytic Stability

The C6H6.Ti(II)(AlBr4)2 (Ib) catalyst deactivates during the butadiene cyclotrimerization to give a solid containing all titanium (mostly as TiBr3) and a mixture of AlBr3 and RAlBr2 compounds dissolved in benzene. The residual cationic catalytic activity of the deactivated Ib system is due to presence of AlBr3. In contrast to TiCl3, the deactivated Ib system and the model system TiBr3 + AlBr3 are not activated by the addition of EtAlCl2 in the presence of butadiene: the highly active benzenetitanium(II) system is re-constituted only after reduction of TiBr3 with Et3Al followed by the addition of EtAlCl2. The addition of Et2AlBr to Ib accelerates the deactivation of the system. Deactivation products of this system contain mainly Ti(II) species which forms benzenetitanium(II) catalytic system after addition of EtAlCl2. All the EtAlCl2 reactivated systems produce (Z, E, E)-1,5,9-cyclododecatriene with high catalytic stability and considerable selectivity (>90%). This behaviour points to the catalysis by benzenetitanium(II) chloroalane complexes containing only low amount of bromine atoms and ethyl groups.

scholarly journals Highly Dispersed Pd Species Supported on CeO2 Catalyst for Lean Methane Combustion: The Effect of the Occurrence State of Surface Pd Species on the Catalytic Activity

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 772
Author(s):  
Yanxiong Liu ◽  
Changhua Hu ◽  
Longchun Bian
Keyword(s):  
Catalytic Activity ◽  
Oxygen Vacancies ◽  
Methane Combustion ◽  
Pd Nanoparticles ◽  
High Concentration ◽  
Ch4 Combustion ◽  
Highly Active ◽  
Δ Phase ◽  
Occurrence State ◽  
Comprehensive Characterization

The correlation between the occurrence state of surface Pd species of Pd/CeO2 for lean CH4 combustion is investigated. Herein, by using a reduction-deposition method, we have synthesized a highly active 0.5% PdO/CeO2-RE catalyst, in which the Pd nanoparticles are evenly dispersed on the CeO2 nanorods CeO2-R. Based on comprehensive characterization, we have revealed that the uniformly dispersed Pd nanoparticles with a particle size distribution of 2.3 ± 0.6 nm are responsible for the generation of PdO and PdxCe1−xO2−δ phase with –Pd2+–O2−–Ce4+– linkage, which can easily provide oxygen vacancies and facilitate the transfer of reactive oxygen species between the CeO2-R and Pd species. As a consequence, the remarkable catalytic activity of 0.5% Pd/CeO2-RE is related to the high concentration of PdO species on the surface of the catalyst and the synergistic interaction between the Pd species and the CeO2 nanorod.

scholarly journals A new highly active La2O3–CuO–MgO catalyst for the synthesis of cumyl peroxide by catalytic oxidation

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12532-12542
Author(s):  
HanShuang Liu ◽  
KaiJun Wang ◽  
XiaoYan Cao ◽  
JiaXin Su ◽  
Zhenggui Gu
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Highly Active

The La2O3–CuO–MgO catalyst acts on the oxidation of cumene and shows excellent catalytic activity through the coordination of surface and interior.

Enhanced catalytic activity over MIL-100(Fe) with coordinatively unsaturated Fe2+/Fe3+ sites for selective oxidation of H2S to sulfur

2019 ◽  
Vol 374 ◽  
pp. 793-801 ◽  
Author(s):  
Xiaoxiao Zheng ◽  
Linyan Zhang ◽  
Zhangjia Fan ◽  
Yanning Cao ◽  
Lijuan Shen ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Selective Oxidation

Selective oxidation of benzyl alcohol to benzaldehyde with H2O2 in water on epichlorohydrin-modified Fe3O4 microspheres

2015 ◽  
Vol 39 (6) ◽  
pp. 4924-4932 ◽  
Author(s):  
Shiwei Xiao ◽  
Chuntao Zhang ◽  
Rong Chen ◽  
Fengxi Chen
Keyword(s):  
Catalytic Activity ◽  
Benzyl Alcohol ◽  
Selective Oxidation ◽  
Title Reaction ◽  
Enhancing Effect ◽  
Oxidation Of Benzyl Alcohol ◽  
Fe3o4 Microspheres

The enhancing effect of modification by epichlorohydrin on the catalytic activity of Fe3O4 microspheres in the title reaction was theoretically and experimentally confirmed.

scholarly journals Nef Associates with p21-Activated Kinase 2 in a p21-GTPase-Dependent Dynamic Activation Complex within Lipid Rafts

2004 ◽  
Vol 78 (23) ◽  
pp. 12773-12780 ◽  
Author(s):  
Kati Pulkkinen ◽  
G. Herma Renkema ◽  
Frank Kirchhoff ◽  
Kalle Saksela
Keyword(s):  
Catalytic Activity ◽  
Lipid Rafts ◽  
Lipid Raft ◽  
Kinase Activity ◽  
Highly Active ◽  
Membrane Compartment ◽  
Per Se ◽  
P21 Activated Kinase ◽  
Autoregulatory Mechanism ◽  
Pak2 Activation

ABSTRACT We have previously reported that Nef specifically interacts with a small but highly active subpopulation of p21-activated kinase 2 (PAK2). Here we show that this is due to a transient association of Nef with a PAK2 activation complex within a detergent-insoluble membrane compartment containing the lipid raft marker GM1. The low abundance of this Nef-associated kinase (NAK) complex was found to be due to an autoregulatory mechanism. Although activation of PAK2 was required for assembly of the NAK complex, catalytic activity of PAK2 also promoted dissociation of this complex. Testing different constitutively active PAK2 mutants indicated that the conformation associated with p21-mediated activation rather than kinase activity per se was required for PAK2 to become NAK. Although association with PAK2 is one of the most conserved properties of Nef, we found that the ability to stimulate PAK2 activity differed markedly among divergent Nef alleles, suggesting that PAK2 association and activation are distinct functions of Nef. However, mutations introduced into the p21-binding domain of PAK2 revealed that p21-GTPases are involved in both of these Nef functions and, in addition to promoting PAK2 activation, also help to physically stabilize the NAK complex.

Vanadium-Chromium Oxide: Effective Catalysts for Ammoxidation of 3-Picoline

2013 ◽  
Vol 634-638 ◽  
pp. 624-627 ◽  
Author(s):  
Feng Jiang ◽  
Wei Xu ◽  
Lei Niu ◽  
Guo Min Xiao
Keyword(s):  
Raman Spectroscopy ◽  
Catalytic Activity ◽  
Chromium Oxide ◽  
Atmospheric Pressure ◽  
High Selectivity ◽  
Surface Acidity ◽  
N2 Adsorption ◽  
Composite Oxide ◽  
Highly Active

Bulk vanadium-chromium oxide (VCrO) catalyst was prepared and characterized by N2 adsorption, XRD, NH3-TPD, H2-TPR, and Raman spectroscopy. XRD and Raman results showed that the VCrO catalyst was a kind of VV-CrIII composite oxide mainly consisted of crystalline V2O5 and CrVO4-Ⅲ (orthorhombic). NH3-TPD and H2-TPR results revealed that this catalyst had negligible surface acidity, and was easily reduced due to the formation of CrVO4-Ⅲ. Their catalytic activity was evaluated in the ammoxidation of 3-picoline to nicotinonitrile. Catalytic results showed that the bulk VCrO catalyst was highly active and selective; the nicotinonitrile selectivity and yield was up to 96.1%, 88.2% respectively at atmospheric pressure and 360 °C. The high selectivity was related closely to the low surface acidity of the catalyst.

Towards highly active heterogeneous catalysts via a sequential noncovalent bonding strategy

2021 ◽  
Author(s):  
Ruixue Wang ◽  
Ying Yue ◽  
Huiying Wei ◽  
Jinxin Guo ◽  
Yanzhao Yang
Keyword(s):  
Catalytic Activity ◽  
Heterogeneous Catalysts ◽  
High Catalytic Activity ◽  
Synthetic Route ◽  
Surface Ligands ◽  
Highly Active ◽  
Noncovalent Bonding ◽  
Excellent Stability

Here, a novel synthetic route of ceria-based nanocatalysts with high catalytic activity and excellent stability was constructed by utilizing function groups from surface ligands. The surface of ceria nanorods were...

scholarly journals Catalytic Activity of Oxidation-Reduction Pre-Treated Ni3Al for Methane Steam Reforming

2010 ◽  
Vol 89-91 ◽  
pp. 645-650 ◽  
Author(s):  
Ya Xu ◽  
Dong Hyun Chun ◽  
Jun Hyuk Jang ◽  
Masahiko Demura ◽  
Dang Moon Wee ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Steam Reforming ◽  
Active Surface ◽  
Methane Steam Reforming ◽  
Reduction Treatment ◽  
Highly Active ◽  
Methane Steam ◽  
Oxidation Reduction ◽  
Pre Treatment ◽  
Oxidation In Air

The catalytic activity of oxidation-reduction pre-treated Ni3Al powder for methane steam reforming was examined. The oxidation-reduction pre-treatment consisted of two steps: oxidation in air at various temperatures from 973 to 1373 K, and then followed by reduction in H2 at 873 K. It was found that the oxidation-reduction treatments significantly reduced the onset temperature of activity, i.e., improved the activity of Ni3Al powder at low temperatures. The characterization of Ni3Al surface showed that an outer surface layer of fine NiO particles were formed on the surface of Ni3Al after oxidation. These NiO particles were reduced to metallic Ni by the subsequent reduction treatment, resulting in the high activity for methane steam reforming. These results indicate that the Ni3Al can form highly active surface structure with oxidation-reduction treatment, having excellent heat resistance.

Facile Synthesis of Ag-Hollandite Nanofibers and Their Catalytic Activity for Ethanol Selective Oxidation

2007 ◽  
Vol 28 (12) ◽  
pp. 1034-1036 ◽  
Author(s):  
Junli CHEN ◽  
Juan LI ◽  
Qiying LIU ◽  
Xiumin HUANG ◽  
Wenjie SHEN
Keyword(s):  
Catalytic Activity ◽  
Selective Oxidation ◽  
Facile Synthesis
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