scholarly journals Au–Ag and Pt–Ag bimetallic nanoparticles@halloysite nanotubes: morphological modulation, improvement of thermal stability and catalytic performance

RSC Advances ◽  
2018 ◽  
Vol 8 (19) ◽  
pp. 10237-10245 ◽  
Author(s):  
Siyu Li ◽  
Feng Tang ◽  
Huixin Wang ◽  
Junran Feng ◽  
Zhaoxia Jin
Keyword(s):  
Thermal Stability ◽  
Bimetallic Nanoparticles ◽  
Catalytic Performance ◽  
Halloysite Nanotubes ◽  
Monometallic Nanoparticles

Bimetallic Au–Ag@HNT and Pt–Ag@HNT nanocages showed significantly improved efficiency in the oxidation of o-phenylenediamine as peroxidase-like catalyst compared with corresponding monometallic nanoparticles.

scholarly journals Isothermal Vulcanization and Non-Isothermal Degradation Kinetics of XNBR/Epoxy/XNBR-g-Halloysite Nanotubes (HNT) Nanocomposites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2872
Author(s):  
Seyed Mohamad Reza Paran ◽  
Ghasem Naderi ◽  
Elnaz Movahedifar ◽  
Maryam Jouyandeh ◽  
Krzysztof Formela ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Degradation Kinetics ◽  
Halloysite Nanotubes ◽  
Butadiene Rubber ◽  
Order Model ◽  
Scanning Calorimetry ◽  
Theoretical Methods ◽  
Vulcanization Kinetics ◽  
Kinetics Of ◽  
Thermal Stability Of

The effect of several concentrations of carboxylated nitrile butadiene rubber (XNBR) functionalized halloysite nanotubes (XHNTs) on the vulcanization and degradation kinetics of XNBR/epoxy compounds were evaluated using experimental and theoretical methods. The isothermal vulcanization kinetics were studied at various temperatures by rheometry and differential scanning calorimetry (DSC). The results obtained indicated that the nth order model could not accurately predict the curing performance. However, the autocatalytic approach can be used to estimate the vulcanization reaction mechanism of XNBR/epoxy/XHNTs nanocomposites. The kinetic parameters related to the degradation of XNBR/epoxy/XHNTs nanocomposites were also assessed using thermogravimetric analysis (TGA). TGA measurements suggested that the grafted nanotubes strongly enhanced the thermal stability of the nanocomposite.

Zn2+ stabilized Pd clusters with enhanced covalent metal–support interaction via the formation of Pd–Zn bonds to promote catalytic thermal stability

Nanoscale ◽  
2020 ◽  
Vol 12 (27) ◽  
pp. 14825-14830
Author(s):  
Kai-Qiang Jing ◽  
Yu-Qing Fu ◽  
Zhi-Qiao Wang ◽  
Zhe-Ning Chen ◽  
Hong-Zi Tan ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Adsorption Energy ◽  
Catalytic Performance ◽  
Support Interaction ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Pd Clusters

Zn2+-Modified MgAl-LDH with ultra-low Pd cluster loading was synthesized. The higher adsorption energy and strong covalent metal–support interaction via forming Pd–Zn bonds over Pd/ZnMgAl-LDH account for the robust catalytic performance.

scholarly journals Pd–Ni Bimetallic Nanoparticles Supported on Zro2 as an Efficient Catalyst for Suzuki–Miyaura Reactions

2018 ◽  
Vol 42 (8) ◽  
pp. 419-423
Author(s):  
Li-Jie Zhang ◽  
Xian Yao ◽  
Ying-xin Sun ◽  
Jia-wei Zhang ◽  
Chun Cai
Keyword(s):  
Reduction Method ◽  
Bimetallic Nanoparticles ◽  
Bimetallic Catalyst ◽  
Cross Coupling ◽  
Catalytic Performance ◽  
Coupling Reactions ◽  
Efficient Catalyst ◽  
Mild Conditions ◽  
Cross Coupling Reactions ◽  
Excellent Catalytic Performance

Pd–Ni bimetallic nanoparticles (BMNPs) supported on ZrO2 were prepared by an impregnation–reduction method. The BMNPs showed excellent catalytic performance in Suzuki carbon–carbon cross-coupling reactions and almost quantitative conversion of the substrates was obtained under mild conditions in the absence of ligand. The excellent catalytic performance of the bimetallic catalyst could be a result of the synergistic effect between the two metal components. The catalyst showed outstanding recyclability during the reaction process; no obvious decrease in catalytic performance was observed after five cycles.

Influences of doping and thermal stability on the catalytic performance of CuO/Ce20M1Ox (M = Zr, Cr, Mn, Fe, Co, Sn) catalysts for NO reduction by CO

RSC Advances ◽  
2016 ◽  
Vol 6 (114) ◽  
pp. 113630-113647 ◽  
Author(s):  
Changshun Deng ◽  
Junning Qian ◽  
Chuxuan Yu ◽  
Yunan Yi ◽  
Pan Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
No Reduction ◽  
Metal Cations ◽  
Catalytic Performance ◽  
Variable Valence ◽  
No Reduction By Co ◽  
Catalysts For No Reduction

The doping of variable valence metal cations into CeO2 is beneficial for catalytic NO reduction by CO.

Comparison of the Catalytic Performance of Ni, Mo, and Ni–Mo Impregnated on Acid Halloysite Nanotubes in the n-Decane Hydroconversion

2019 ◽  
Vol 33 (12) ◽  
pp. 12647-12655 ◽  
Author(s):  
J. A. Torres-Luna ◽  
S. Moreno ◽  
R. Molina ◽  
J. G. Carriazo
Keyword(s):  
Catalytic Performance ◽  
Halloysite Nanotubes

Pt/UiO-66 Nanocomposites as Catalysts for CO2 Methanation Process

2019 ◽  
Vol 19 (6) ◽  
pp. 3187-3196 ◽  
Author(s):  
Maria Mihet ◽  
Gabriela Blanita ◽  
Monica Dan ◽  
Lucian Barbu-Tudoran ◽  
Mihaela D Lazar
Keyword(s):  
Thermal Stability ◽  
Surface Area ◽  
Metal Organic Framework ◽  
Catalytic Performance ◽  
Molar Ratio ◽  
High Dispersion ◽  
Co2 Methanation ◽  
Preparation Methods ◽  
Good Thermal Stability ◽  
Catalytic Support

Pt/UiO-66 nanocomposites with platinum target concentration of 3 wt.% were prepared by 3 preparation methods, characterized and tested in the CO2 methanation process. Choice of the microporous UiO-66 metal-organic framework (Zr6O4(OH)4 with 1,4-benzene-dicarboxylate ligand) as catalytic support was motivated by the CO2 chemisorption capacity (proven by CO2-TPD profiles), large specific surface area (1477 m2/g) which favors a high dispersion of metal nanoparticles and good thermal stability. The preparation methods for the Pt/UiO-66 nanocomposites are: (1) wetimpregnation followed by reduction in H2 at 200 °C for 2 h; (2) wet-impregnation followed by reduction with an aqueous solution of NaBH4; and (3) “double-solvent” method, followed by reduction with NaBH4. The UiO-66 based nanocomposites were characterized by N2 adsorption–desorption (BET method), XRD, and SEM/TEM. The Pt/UiO-66 catalyst prepared by method 3 was chosen for catalytic testing due to its highest surface area, smallest platinum nanoparticles (PtNPs) size, the localization of PtNPs both on the grain’s internal and external surface and best thermal stability in the desired temperature range. Its capacity to adsorb and activate CO2 and H2 was evaluated in thermo-programmed desorption experiments (H2-TPD and CO2-TPD). Hydrogen is molecularly adsorbed, while CO2 is adsorbed both molecularly and dissociatively. The catalytic performance in the CO2 methanation process was evaluated by Temperature Programmed Reactions (TPRea, 2 °C/min, 30–350 °C), at atmospheric pressure. The best results were obtained at 350 °C, CO2:H2 molar ratio of 1:5.2 and GHSV ═ 1650 h−1. In these conditions CO2 conversion is almost 50% and CH4 selectivity is 36%, the rest of the converted CO2 being transformed in CO.

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