scholarly journals Preparation of Magnetic CuFe2O4@Ag@ZIF-8 Nanocomposites with Highly Catalytic Activity Based on Cellulose Nanocrystals

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 124 ◽  
Author(s):  
Sufeng Zhang ◽  
Yongshe Xu ◽  
Dongyan Zhao ◽  
Wenqiang Chen ◽  
Hao Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Cellulose Nanocrystals ◽  
Environmental Chemistry ◽  
Magnetic Core ◽  
In Situ Reduction ◽  
Ag Nps ◽  
N2 Adsorption ◽  
Ag Catalyst ◽  
Adsorption Desorption

A facile approach was successfully developed for synthesis of cellulose nanocrystals (CNC)-supported magnetic CuFe2O4@Ag@ZIF-8 nanospheres which consist of a paramagnetic CuFe2O4@Ag core and porous ZIF-8 shell. The CuFe2O4 nanoparticles (NPs) were first prepared in the presence of CNC and dispersant. Ag NPs were then deposited on the CuFe2O4/CNC composites via an in situ reduction directed by dopamine polymerization (PDA). The CuFe2O4/CNC@Ag@ZIF-8 nanocomposite was characterized by TEM, FTIR, XRD, N2 adsorption-desorption isotherms, VSM, and XPS. Catalytic studies showed that the CuFe2O4/CNC@Ag@ZIF-8 catalyst had much higher catalytic activity than CuFe2O4@Ag catalyst with the rate constant of 0.64 min−1. Because of the integration of ZIF-8 with CuFe2O4/CNC@Ag that combines the advantaged of each component, the nanocomposites were demonstrated to have an enhanced catalytic activity in heterogeneous catalysis. Therefore, these results demonstrate a new method for the fabrication of CNC-supported magnetic core-shell catalysts, which display great potential for application in biocatalysis and environmental chemistry.

Au-on-Ag nanostructure for in-situ SERS monitoring of catalytic reactions

2022 ◽  
Author(s):  
Shuyue He ◽  
Di Wu ◽  
Siwei Chen ◽  
Kai Liu ◽  
Eui-Hyeok Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Thermal Evaporation ◽  
Reduction Process ◽  
Ag Nps ◽  
Au Nps ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Raman Probe

Abstract Dual-functionality Au-on-Ag nanostructures (AOA) were fabricated on a silicon substrate by first immobilizing citrate-reduced Ag nanoparticles (Ag NPs, ~43 nm in diameter), followed by depositing ~7 nm Au nanofilms (Au NFs) via thermal evaporation. Au NFs were introduced for their catalytic activity in concave-convex nano-configuration. Ag NPs underneath were used for their significant enhancement factor (EF) in surface-enhanced Raman scattering (SERS)-based measurements of analytes of interest. Rhodamine 6G (R6G) was utilized as the Raman-probe to evaluate the SERS sensitivity of AOA. The SERS EF of AOA is ~37 times than that of Au NPs. Using reduction of 4-nitrothiophenol (4-NTP) by sodium borohydride (NaBH4) as a model reaction, we demonstrated the robust catalytic activity of AOA as well as its capacity to continuously monitor via SERS the disappearance of reactant 4-NTP, emergence and disappearance of intermediate 4, 4’-DMAB, and the appearance of product 4-ATP throughout the reduction process in real-time and in situ.

Catalytic Activity of Dehydrogenation of Methanol to MF over Cu/MCM-41 and Cu-ZnO/MCM-41 Prepared by Impregnation and Grinding

2011 ◽  
Vol 396-398 ◽  
pp. 730-733
Author(s):  
Guo Ru Li ◽  
Gong Li ◽  
Shu Xi Zhou ◽  
Hui Juan Tong
Keyword(s):  
Catalytic Activity ◽  
Atmospheric Pressure ◽  
Molecular Sieves ◽  
Conversion Rate ◽  
Methyl Formate ◽  
Methanol Conversion ◽  
N2 Adsorption ◽  
Flow Microreactor ◽  
Adsorption Desorption ◽  
Mcm 41

Abstract. Using MCM-41 molecular sieves as the support, Cu-ZnO/MCM-41 and Cu/MCM-41 catalysts were prepared by impregnation and grinding. The catalysts were characterized by XRD, N2 adsorption-desorption and TPR methods. The catalytic activity of the dehydrogenation of methanol to methyl formate (MF) was evaluated using the flow microreactor under atmospheric pressure. According to the results, the catalyst prepared by impregnation had a better selectivity for the MF, but a lower methanol conversion rate. However, the product's selectivity could be improved by adding ZnO additive while the methanol conversion rate was reduced. For Cu/MCM-41 prepared by impregnation and grinding, the methanol conversion rate was 20.18% and 24.13% respectively at 250°C and the MF selectivity was 73.75% and 67.35% respectively. Likewise for Cu-ZnO/MCM-41 prepared by impregnation and grinding, the methanol conversion rate was 15.28% and 18.83% respectively at 250°C and the MF selectivity was 81.31% and 75.32% respectively.

scholarly journals Oxidative Desulfurization of Dibenzothiophene Using Dawson Type Heteropoly Compounds/Tantalum as Catalyst

2018 ◽  
Vol 16 (1) ◽  
pp. 105 ◽  
Author(s):  
Risfidian Mohadi ◽  
Lusi Teresia ◽  
Najma Annuria Fithri ◽  
Aldes Lesbani ◽  
Nurlisa Hidayati
Keyword(s):  
Catalytic Activity ◽  
Vibration Spectrum ◽  
Oxidative Desulfurization ◽  
Heteropoly Compounds ◽  
Atmospheric Conditions ◽  
N2 Adsorption ◽  
Fresh Catalyst ◽  
Wet Impregnation ◽  
Percent Conversion ◽  
Adsorption Desorption

Catalyst (NH4)6[b-P2W18O62]/Ta has been synthesized by simple wet impregnation at 30-40 °C under atmospheric conditions using Dawson type polyoxometalate (NH4)6[b-P2W18O62] and tantalum. The catalyst was characterized by FTIR spectrophotometer, XRD, SEM, and N2 adsorption desorption methods. FTIR spectrum of (NH4)6[b-P2W18O62]/Ta showed that Dawson type polyoxometalate (NH4)6[b-P2W18O62] and Ta was successfully impregnated which was indicated by vibration spectrum at wavenumber of 900-1100 cm-1 for polyoxometalate and 550 cm-1 for Ta. The surface area of the (NH4)6[b-P2W18O62]/Ta after impregnation was higher than (NH4)6[b-P2W18O62]•nH2O and its morphology was found to be uniform. The catalytic activity of (NH4)6[b-P2W18O62]/Ta toward desulfurization of dibenzothiophene was three times higher than the original catalyst of (NH4)6[b-P2W18O62]•nH2O without impregnation. The catalytic regeneration test of catalyst (NH4)6[b-P2W18O62]/Ta showed that the catalytic activity for first regeneration of catalyst has similar catalytic activity with the fresh catalyst without loss of catalytic activity indicated by almost similar percent conversion.

The Application of Mesoporous ZSM-5 Zeolite in the ULSD Catalysts

2020 ◽  
Vol 4 (4) ◽  
pp. 1-3
Author(s):  
Liu L
Keyword(s):  
Catalytic Performance ◽  
Nitrogen Compounds ◽  
In Situ Ftir ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
X Ray ◽  
Acidic Sites ◽  
Adsorption Desorption ◽  
Al2o3 Catalyst

The mesoporous ZSM-5 zeolite containing MoCoP/Al2O3 catalyst (C12-ZSM5) with the mixture of Al2O3 and mesoporous ZSM- 5 zeolite as carrier was synthesized. The catalytic performance of C12-ZSM5 catalyst was evaluated by the hydrodesulfurization (HDS) of different diesel feedstock. The carriers and catalysts were characterized by N2 adsorption-desorption, pyridine-FTIR, X-ray diffraction (XRD) and CO in-situ FTIR (CO-FTIR) techniques. Results showed that mesoporous ZSM-5 can improve the acidity of the catalyst and increase the number of MoCoS active phases. The C12-ZSM5 catalyst had low HDS and HDN activity, because the acidic sites of mesoporous ZSM-5 were easily occupied by nitrogen compounds. The HDS activity of C12-ZSM5 catalyst was fully exploited by using graded packing technology, the sulfur content of product oil was 5.9 ng/μL. The relative HDS activity of C12-ZSM5 catalyst is 1.47 times that of FHUDS-8 catalyst.

In situ reduction of well-dispersed nickel nanoparticles on hierarchical nickel silicate hollow nanofibers as a highly efficient transition metal catalyst

RSC Advances ◽  
2016 ◽  
Vol 6 (39) ◽  
pp. 32580-32585 ◽  
Author(s):  
Yang Yang ◽  
Renxi Jin ◽  
Shuo Zhao ◽  
Jihong Liu ◽  
Yunfeng Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Nickel Nanoparticles ◽  
Metal Catalyst ◽  
Ni Nanoparticles ◽  
In Situ Reduction ◽  
Hollow Nanofibers ◽  
Transition Metal Catalyst ◽  
Nickel Silicate

Ni nanoparticles were immobilized on the hierarchically double-shell nickel silicate hollow nanofibers, the composites exhibited an excellent catalytic activity.

Pd/meso-CoO derived from in situ reduction of the one-step synthesized Pd/meso-Co3O4: high-performance catalysts for benzene combustion

2019 ◽  
Vol 43 (31) ◽  
pp. 12358-12368 ◽  
Author(s):  
Xingtian Zhao ◽  
Ran Zhang ◽  
Yuxi Liu ◽  
Jiguang Deng ◽  
Peng Xu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Performance ◽  
Oxygen Activation ◽  
In Situ Reduction ◽  
Templating Method ◽  
One Step ◽  
The One

The 0.93Pd/meso-CoO is prepared via in situ reduction of 0.85Pd/meso-Co3O4 derived from KIT-6-templating method. The excellent catalytic activity of 0.93Pd/meso-CoO is related to the formed Pd0 species and good oxygen activation ability.

Structure, Acid Properties and Catalysis Performance of MCM-22 “Family” Zeolites on the Alkylation of Benzene with Propylene

2012 ◽  
Vol 549 ◽  
pp. 283-286 ◽  
Author(s):  
Fei Zhao ◽  
Yu Zhang ◽  
Shu Dong Geng ◽  
Lian Fa Chen ◽  
Wei Wang
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Reaction Temperature ◽  
Dynamic Method ◽  
N2 Adsorption ◽  
Acid Properties ◽  
Low Reaction Temperature ◽  
Alkylation Of Benzene ◽  
Adsorption Desorption

MCM-22 “family” zeolites (MCM-22, MCM-49 and MCM-56) have been synthesized hydrothermally by dynamic method. All materials were characterized by different techniques, such as XRD, N2 adsorption-desorption and NH3-TPD. The catalyst performance of MCM-22 “family” zeolites have been studied on the alkylation of benzene with propylene in liquid phase. Result shows that MCM-22 “family” zeolites are excellent alkylation catalysts for the produce of cumene. Compared to MCM-22 and MCM-49, MCM-56 shows higher catalytic activity in a relatively low reaction temperature and higher monoalkylation selectivity in a relatively low benzene-to-propylene ratio.

PtCo Nanoparticles Supported on Carbon for Hydrolysis of Ammonia Borane

2016 ◽  
Vol 852 ◽  
pp. 252-256
Author(s):  
Wei Dong Qi ◽  
Li Xian Sun ◽  
Fen Xu ◽  
Yong Jin Zou ◽  
Hai Liang Chu
Keyword(s):  
Catalytic Activity ◽  
Reduction Method ◽  
Hydrogen Generation ◽  
Specific Area ◽  
Ammonia Borane ◽  
In Situ Reduction ◽  
Immersion Method ◽  
Good Catalytic Activity ◽  
Hydrolysis Of

Ammonia borane received extensive attention due to its hydrogen content as high as 19.6%. In present article we prepared the Pt-Co/C catalyst via ultrasonic immersion method and in situ reduction method. The catalyst was characterized by measuring the specific area. The influence of the catalyst on the properties of the hydrolysis of ammonia borane was tested, and the catalytic activity of the catalyst in cycle use was verified. Results shows that the catalytic activity of Pt0.5Co0.5/C is the highest, and the maximum hydrogen generation rate is 7229.613 mL/ (g ·min). It was verified that it remained good catalytic activity after cycle use for more than 10 times.

scholarly journals Synthesis, characterization and catalytic properties of SAPO-11 molecular sieve synthesized in hydrothermal media using di-isopropylamine as template

2014 ◽  
Vol 62 (3) ◽  
pp. 481-488 ◽  
Author(s):  
T. Chellappa ◽  
M. Jose Fonseca Costa ◽  
W.A. Nascimento ◽  
L. Ferreira De Lima ◽  
I. Almeida Bassan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieve ◽  
Catalytic Properties ◽  
Single Agent ◽  
Catalytic Performance ◽  
Organic Template ◽  
N2 Adsorption ◽  
Bet Analysis ◽  
High Crystallization ◽  
Adsorption Desorption

Abstract A microporous SAPO-11 Molecular sieve was successfully synthesized by the hydrothermal method, using a single agent, as an organic template: di-isopropylamine (DIPA). The obtained solid was calcined at 550◦C for three hours, after which the flow of nitrogen was exchanged for that of synthetic air and submitted for another ten hours of calcination, so as to remove the single agent: di-isopropylamine, which after the removal of the template could be observed by the high crystallization of the sample. Furthermore, the molecular sieve was characterized by XRD, SEM, TG-DTG and N2 adsorption desorption (BET analysis). The obtained catalyst proved to have a high potential catalytic activity and selectivity, through the obtained characterization results, exhibiting good hydrothermal stability. The catalytic performance of SAPO-11 was tested by the deactivation/regenerability of the coked sample, furthered by cracking of n-hexane reaction and high olefins selectivity was obtained.

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