Method for constructing monatomic catalyst based on lignin/metal supramolecular assembly

A technology of lignin and catalyst, applied in the direction of physical/chemical process catalysts, chemical instruments and methods, catalyst activation/preparation, etc., can solve the problems of high raw material cost, poor universality, complex process, etc., achieve low cost and increase space The effect of distance and simple process

Active Publication Date: 2018-07-06
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method is not universally applicable
In summary, the existing methods for preparing metal single-atom catalysts all have disadvantages such as complex process, high raw material cost,

Method used

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  • Method for constructing monatomic catalyst based on lignin/metal supramolecular assembly
  • Method for constructing monatomic catalyst based on lignin/metal supramolecular assembly
  • Method for constructing monatomic catalyst based on lignin/metal supramolecular assembly

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Embodiment 1: the synthesis of metal single atom catalyst precursor

[0021] 1) Dissolve 8g of lignin in 1L of deionized water to form solution A. Zinc nitrate hexahydrate (11.90g, 40mmol Zn 2+ ) and cobalt nitrate hexahydrate (2.33g, 8mmol Co 2+ ) was dissolved in 0.5L deionized water to prepare solution B.

[0022] 2) Add solution B to solution A, mix quickly with mechanical stirring, the pH is natural (pH ~ 6.1), the mixture continues to stir for 1 hour, and then stands overnight at room temperature.

[0023] 3) Pour off the supernatant, centrifuge at 5,000×g for 10 minutes, and dry the precipitate at 80°C overnight to obtain a metallic cobalt single-atom catalyst precursor, named Co 1 Zn 5 -L.

[0024] 4) Similarly, by replacing metal cobalt with other metal ions, such as iron, nickel, copper, manganese, zirconium, molybdenum, etc., a lignin / metal supramolecular assembly was obtained, named M 1 Zn 5 -L(M represents a metal ion, such as Fe 3+ , Ni 2+ ,Cu 2+...

Embodiment 2

[0029] Embodiment 2: the synthesis of metal single atom catalyst

[0030] 1) Take 0.1g lignin / metal cobalt catalyst precursor Co 1 Zn 5 -L and 1g of dicyandiamide, thoroughly grind and mix.

[0031] 2) Put the ground powder into a porcelain boat and put it in a tube furnace with an argon flow rate of 75mL / min. The temperature was raised to 900°C / min, and then naturally cooled to room temperature after holding for 3 hours to obtain a nitrogen-doped carbon-supported cobalt single-atom catalyst.

[0032] 3) Similarly, the lignin / metal supramolecular assembly of lignin / metal supramolecular assembly M 1 Zn 5 -L(M represents a metal ion, such as Fe 3+ , Ni 2+ ,Cu 2+ ,Mn 2+ , Zr 2+ ,Mo 2+ ; L represents lignin), and 1g of dicyandiamide, fully ground and mixed. The mass ratio of metal precursor to dicyandiamide is 1:10, the temperature is programmed to 900°C, and sintered at high temperature to obtain a nitrogen-doped carbon-supported metal single-atom catalyst.

[0033] 4...

Embodiment 3

[0035] Example 3: Activity Evaluation of Metal Single Atom Catalysts

[0036] 1) Add 10mL of methanol, 1mmol of benzyl alcohol and 2.5mol% metal cobalt single-atom catalyst into a 100mL round bottom flask, and 0.25mmol of anisole as an internal standard.

[0037] 2) Replace the air in the round-bottomed flask with pure oxygen earlier, at 1bar O 2 (Oxygen balloon), react under the condition of 60 DEG C, take samples regularly, and analyze the reaction product by HPLC. The analysis conditions are: chromatographic column C18, column temperature 30°C, mobile phase 30% acetonitrile and 70% water (containing 0.05v% trifluoroacetic acid), flow rate 1mL / min, UV detector 254nm.

[0038] 3) The catalyst is replaced with other metal single-atom catalysts (such as iron, nickel, copper, manganese, zirconium, molybdenum, etc.) to catalyze the oxidative esterification of benzyl alcohol and methanol to prepare methyl benzoate, and the reaction system and product detection conditions remain u...

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Abstract

The invention relates to a method for constructing a monatomic catalyst based on lignin/metal supramolecular assembly and belongs to the technical fields of preparation method of a catalytic materialand application of lignin. The method mainly comprises the following steps: 1) mixing a lignin and metal ionic solution with a certain concentration uniformly and adjusting the pH to form lignin/metalsupramolecular assembly precipitate; 2) centrifuging and drying to obtain a catalyst precursor; and 3) mixing the precursor and a nitrogen source and performing program high-temperature sintering under the protection of inert gas to obtain the monatomic catalyst. Compared with the prior art, the method has distinct characteristics of low raw material cost (the lignin serves as a ligand and a carrier), simple process (pH regulation and control of the precursor and stripping without acid washing), metal dispersing uniformity (coordinated complexation and increment of defect site regulation andcontrol) and the like, and large-scale production of the monatomic catalyst is easily realized.

Description

technical field [0001] The patent of the invention belongs to the technical field of catalytic material preparation and lignin application, and specifically relates to a method for constructing a single-atom catalyst based on lignin / metal supramolecular assembly. Background technique [0002] Supported heterogeneous catalysts are of great significance for improving the recovery and stability of catalysts, reducing catalyst costs, and reducing environmental pollution. They are widely used in energy storage and conversion, organic synthesis, drug preparation, and environmental governance. Studies have shown that the active components of supported metal catalysts are mainly metals, and the active sites are concentrated on the atoms on the particle surface. Therefore, the synthesis of smaller sized particles is an effective approach to improve the activity and selectivity of metal catalysts. [0003] In recent years, metal single-atom catalysts have achieved the maximum utiliza...

Claims

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Application Information

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IPC IPC(8): B01J27/24B01J35/00B01J37/08
CPCB01J27/24B01J35/0046B01J35/006B01J37/082B01J37/086
Inventor 刘云周华
Owner BEIJING UNIV OF CHEM TECH
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