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Carbon supported core-shell structure nano metal catalyst as well as preparation method and application thereof

A core-shell structure, nano-metal technology, applied in the direction of metal/metal oxide/metal hydroxide catalysts, chemical instruments and methods, preparation of hydroxyl compounds, etc., can solve the problem of easy oxidation and deactivation of catalysts, conversion rate and selectivity one after another , equipment requirements and other issues, to achieve good catalytic hydrogenation performance, improve chemical stability, improve the effect of structural stability

Inactive Publication Date: 2015-02-18
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Nano-transition metal catalysts are easily oxidized in air and difficult to preserve in air. In Journal of Molecular Catalysis A:Chemical, 280 (2008) 52-60, Kamal Kouachi et al. prepared cobalt-based different carrier catalysts by impregnation method. It is clearly stated in the literature of hydrocitral that this type of catalyst is easily oxidized and deactivated, so hydrogen must be used for pre-reduction before the hydrogenation reaction starts, thus resulting in a complex operation process and increased requirements for equipment; in Applied Catalysis A: General, 232 (2002) 147-158, Evandro Luís Linhari Rodrigues et al. use impregnation method to SiO 2 Prepare Co / SiO as a carrier 2 Catalyst, due to the property that Co is easily oxidized in the air, can only be used for meteorological hydrogenation, and it needs to be reduced with a large amount of high-pressure hydrogen, which increases the cost of the catalyst
Co / Al was synthesized by Chie Ando et al. in Applied Catalysis A: General, 185 (1999) L181–L183 2 o 3 Catalyst, and hydrogenation reaction to a variety of unsaturated aldehydes with different structures. It can be seen from the results that the conversion rate and selectivity of the reaction fluctuate one after another, and the ideal effect cannot be achieved at the same time.

Method used

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  • Carbon supported core-shell structure nano metal catalyst as well as preparation method and application thereof
  • Carbon supported core-shell structure nano metal catalyst as well as preparation method and application thereof
  • Carbon supported core-shell structure nano metal catalyst as well as preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] 0.006mol (CH 3 COO) 2 Co 4H 2 O, 0.006mol (CH 3 COO) 2 Zn·2H2 O, 0.003mol Al(NO 3 ) 3 9H 2 O was dissolved in 30ml deionized water as solution A. Another 0.024mol NaOH, 0.0075mol CH 3 COONa was dissolved in 30ml deionized water as solution B. Slowly pour solution A and solution B into the colloid mill (4000rpm), fully stir and mix for 3 minutes, centrifuge the slurry and wash it 3 times to make it neutral, fully disperse the slurry in 60ml deionized water, transfer to 80ml poly Crystallized at 140°C for 8 hours in a vinyl fluoride reactor, then centrifuged and washed to obtain CoZnAl-LDH. The obtained CoZnAl-LDH slurry and 0.00225mol β-cyclodextrin were dispersed in 100ml deionized water at 80°C and stirred until all the water evaporated to obtain a CoZnAl-LDH / β-cyclodextrin complex.

[0022] The CoZnAl-LDH / β-cyclodextrin complex prepared above was placed in a tube atmosphere furnace under N 2 Under the atmosphere (60mL / min), the temperature was raised to 200...

Embodiment 2

[0025] 0.009mol (CH 3 COO) 2 Co 4H 2 O, 0.003mol (CH 3 COO) 2 Zn·2H 2 O, 0.003mol Al(NO 3 ) 3 9H 2 O was dissolved in 30ml deionized water as solution A. Another 0.02mol NaOH, 0.005mol CH 3 COONa was dissolved in 30ml deionized water as solution B. Slowly pour solution A and solution B into the colloid mill (4000rpm), fully stir and mix for 3 minutes, centrifuge the slurry and wash it 3 times to make it neutral, fully disperse the slurry in 60ml deionized water, transfer to 80ml poly Crystallized at 170°C for 6 hours in a vinyl fluoride reactor, then centrifuged and washed to obtain CoZnAl-LDH. The obtained CoZnAl-LDH slurry and 0.00225mol β-cyclodextrin were dispersed in 100ml deionized water at 80°C and stirred until all the water evaporated to obtain a CoZnAl-LDH / β-cyclodextrin complex.

[0026] The CoZnAl-LDH / β-cyclodextrin complex prepared above was placed in a tube atmosphere furnace under N 2 Under the atmosphere (80mL / min), the temperature was raised to 250...

Embodiment 3

[0029] 0.003mol (CH 3 COO) 2 Co 4H 2 O, 0.009mol (CH 3 COO) 2 Zn·2H 2 O, 0.003mol Al(NO 3 ) 3 9H 2 O was dissolved in 30ml deionized water as solution A. Another 0.024mol NaOH, 0.005mol CH 3 COONa was dissolved in 30ml deionized water as solution B. Slowly pour solution A and solution B into the colloid mill (4000rpm), fully stir and mix for 6 minutes, centrifuge the slurry and wash it 3 times to make it neutral, fully disperse the slurry in 60ml deionized water, transfer to 80ml poly Crystallized at 150°C for 10 hours in a vinyl fluoride reactor, then centrifuged and washed to obtain CoZnAl-LDH. The obtained CoZnAl-LDH slurry and 0.0015mol β-cyclodextrin were dispersed in 100ml deionized water at 80°C and stirred until all the water evaporated to obtain a CoZnAl-LDH / β-cyclodextrin complex.

[0030] The CoZnAl-LDH / β-cyclodextrin complex prepared above was placed in a tube atmosphere furnace under N 2 Under the atmosphere (100mL / min), the temperature was raised to 3...

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Abstract

The invention provides a carbon supported core-shell structure nano metal catalyst as well as a preparation method and application thereof. The carbon supported metal catalyst with the core-shell structure is obtained by compounding layered double-metal hydroxides containing cobalt and nickel and beta-cyclodextrin and self-reducing the compound in situ at a high temperature by means of the reducibility of generating carbon at the high temperature of the beta-cyclodextrin; the carbon supported metal catalyst with the core-shell structure can be expressed as M / ZnO-Al2O3 / C; and the core of the carbon supported metal catalyst is formed by nano metal M (M is Co or Ni), and the shell of the catalyst is formed by ZnO and little amorphous Al2O3; amorphous carbon serves as the catalyst carrier; the grain sizes of the core-shell structure nanoparticles are distributed in the range of 15-40 nm; and the specific surface area of the catalyst is 150-350 m<2> / g. The carbon supported metal catalyst is applied to hydrogenation reaction of citronellal and shows excellent activity; and the carbon supported metal catalyst has high selectivity for the product citronellal.

Description

technical field [0001] The invention relates to the technical field of catalyst preparation, in particular to a preparation method of a carbon-loaded core-shell structure nano-metal catalyst. The catalyst is used for the selective catalytic hydrogenation of citronellal. technical background [0002] Layered double hydroxides (LDHs), whose molecular formula is [M 2+ (1-x) m 3+ x (OH) 2 ] x+ (A x / n ) n- .mH 2 O, is an anionic clay material with a typical layered structure. Due to its composition M 2+ ,M 3+ As well as the size controllability, it has important applications in the field of catalysis. Using LDHs as substrates to prepare highly dispersed catalysts combined with other materials has been widely used in various organic catalysis fields. With the development of science and technology, carbon materials have touched all walks of life. Since carbon materials have high specific surface area and good thermal and mechanical properties, loading catalysts on carb...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/80C07C33/025C07C29/141
Inventor 杨兰蒋中山李峰范国利
Owner BEIJING UNIV OF CHEM TECH
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