Nickel monatomic catalyst and preparation method and application thereof

A catalyst and atomic technology, applied in the direction of catalyst activation/preparation, chemical instruments and methods, physical/chemical process catalysts, etc. Low atomic load and other issues, to achieve the effect of low cost, weakened surface tension, and high loading rate

Pending Publication Date: 2022-07-01
SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

High temperature treatment may lead to weakened or even dislocated metal-organic / inorganic molecular coordination, making metal ions tend to aggregate into clusters or nanoparticles during annealing, resulting in a significant reduction in the loading of metal single atoms
Therefore, the loading of metal single atoms in carbon-based supported catalysts synthesized by the conventional “bottom-up” strategy is usually relatively low (less than 2 wt%), which will limit their practical applications.

Method used

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  • Nickel monatomic catalyst and preparation method and application thereof
  • Nickel monatomic catalyst and preparation method and application thereof
  • Nickel monatomic catalyst and preparation method and application thereof

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preparation example Construction

[0040] One aspect of the present invention provides a method for preparing a nickel single-atom catalyst, comprising the following steps:

[0041] Provide chitosan sol, sodium silicate aqueous solution and nickel salt aqueous solution respectively; mix sodium silicate aqueous solution and chitosan sol, adjust pH value to 5-7, add nickel salt aqueous solution to prepare reaction system; The reaction system was oscillated with frequency to obtain nickel-chitosan-sodium silicate composite hydrogel; the nickel-chitosan-sodium silicate composite hydrogel was coagulated by supercritical fluid with temperature > 243.1 °C and pressure > 6.39 kPa The glue is dried and carbonized;

[0042] Wherein, the chitosan sol is prepared by dissolving chitosan in an acetic acid aqueous solution to obtain an acid aqueous solution, and the acid aqueous solution is one or more of an acetic acid aqueous solution, a citric acid aqueous solution and an aqueous hydrochloric acid solution.

[0043] By us...

Embodiment 1

[0073] 10 mL of sodium silicate solution (Na 2 O and SiO 2 The ratio of the amount of substances is 1:1, SiO 2 Concentration 100mg / mL) was added to 40mL of chitosan sol with a concentration of 50mg / mL (solvent: acetic acid aqueous solution with a mass percentage of 1%), adjusted pH to 6.5 after thorough mixing, and then added 3.16mL of freshly prepared nickel nitrate Solution (50mg / L, with Ni 2+ The reaction system was immediately oscillated at a frequency of 50 Hz with a vortex mixer, and the ternary system was ultra-fast co-gelated within 2 s to obtain a homogeneous nickel-chitosan-sodium silicate composite hydrogel; temperature and The nickel-chitosan-sodium silicate composite hydrogel was simultaneously dried and carbonized for 4 h with ethanol supercritical fluid at 300 °C and 10 kPa, respectively, to obtain a nickel single-atom catalyst with a nickel single-atom loading of 5.3%. As 5.3% Ni-C-Si.

Embodiment 2

[0075] 10 mL of sodium silicate solution (Na 2 O and SiO 2 The ratio of the amount of substances is 1:1, SiO 2 Concentration 100mg / mL) was added to 40mL of chitosan sol with a concentration of 50mg / L (solvent: acetic acid aqueous solution with a mass percentage of 1%), adjusted pH to 6.5 after thorough mixing, and then added 6.67mL of freshly prepared nickel nitrate Solution (50mg / L, with Ni 2+ The reaction system was immediately oscillated at a frequency of 50 Hz with a vortex mixer, and the system ultra-fast co-gelation within 2 s to obtain a homogeneous nickel-chitosan-sodium silicate composite hydrogel, denoted as 10% Ni -CS-Si; The nickel-chitosan-sodium silicate composite hydrogel was dried and carbonized for 4 h by using ethanol supercritical fluid with temperature and pressure of 300 °C and 10 kPa, respectively, to obtain a nickel single atom loading of 10.7%. Nickel single-atom catalyst, denoted as 10.7% Ni-C-Si.

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Abstract

The invention relates to the technical field of nano catalytic materials, in particular to a nickel monatomic catalyst and a preparation method and application thereof. According to the preparation method, chitosan sol is adopted to provide a carbon source, a sodium silicate aqueous solution is adopted to provide a silicon source, the chitosan sol and the sodium silicate aqueous solution are mixed with a nickel salt aqueous solution within a proper pH range, and nickel-chitosan-sodium silicate ternary composite hydrogel with high nickel dispersion is rapidly formed under the supramolecular complexing action of the three components; the temperature is 243.1 DEG C, and the pressure is gt; and carrying out synchronous drying and carbonization treatment on the supercritical fluid with the pressure of 6.39 kPa to prepare the nickel monatomic catalyst. The preparation method is simple to operate, prevents excessive degradation of a pore network structure of the hydrogel, can furthest avoid the problem that metal atoms are easy to agglomerate due to high-temperature carbonization treatment in a conventional technology, effectively improves the loading capacity of nickel monatomic on a carbon-based carrier, and endows the nickel monatomic catalyst with excellent catalytic performance.

Description

technical field [0001] The invention relates to the technical field of nano-catalyst materials, in particular to a nickel single-atom catalyst and a preparation method and application thereof. Background technique [0002] Single-atom catalysts (SACs) are a new type of catalytic materials that have emerged in recent years. SACs are usually formed by the uniform distribution of single metal atoms on a support. Compared with traditional supported catalysts, SACs have nearly 100% atomic utilization, high activity, good selectivity, excellent catalytic performance in various reactions, and greatly reduce the cost of noble metal catalysts. At present, a variety of SACs have been used in environmental, biological and other catalytic fields. [0003] As an inexpensive metal, nickel is widely used in a variety of new chemical reactions, such as photocatalytic reactions, CO 2 Reduction, water splitting for hydrogen analysis, etc., have the advantages of green environmental protecti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/224B01J23/755B01J37/08C02F1/30C02F101/34C02F101/38
CPCB01J27/224B01J23/755B01J37/08B01J35/004C02F1/30C02F2101/34C02F2101/38
Inventor 乔涵索红日刘崇炫胡世文唐港
Owner SOUTH UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA
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