阅读说明：本技术 一种Co-N双掺杂生物质多孔碳球的析氧反应催化剂及制法 (Oxygen evolution reaction catalyst of Co-N double-doped biomass porous carbon spheres and preparation method thereof ) 是由 蒋焯文 于 2020-11-18 设计创作，主要内容包括：本发明涉及锌-空气电池领域,且公开了一种Co-N双掺杂生物质多孔碳球的析氧反应催化剂,以木质素微球作为生物质碳源,偕胺肟官能团作为氮源,碳化得到N掺杂多孔碳球,具有丰富的介孔结构和超高的比表面积,Co~(2+)热还原形成Co纳米粒子,高度分散在N掺杂多孔碳球的基体中,减少了Co纳米粒子的团聚和聚集,分散均匀的Co纳米粒子更好地与相邻的活性氮结构形成Co-N_x活性位点,作为析氧反应的活性催化中心,在多孔碳球基体和高度分散的Co-N_x催化活性中心的协同作用下,使析氧反应催化剂表现出高度的析氧起始电位和析氧半波电位,具有优异的析氧反应催化活性。(The invention relates to the field of zinc-air batteries, and discloses an oxygen evolution reaction catalyst of a Co-N double-doped biomass porous carbon sphere, wherein a lignin microsphere is used as a biomass carbon source, an amidoxime functional group is used as a nitrogen source, and the N-doped porous carbon sphere is obtained by carbonization, has a rich mesoporous structure and an ultrahigh specific surface area, and is Co 2+ Co nano particles are formed by thermal reduction and are highly dispersed in a matrix of the N-doped porous carbon spheres, the agglomeration and aggregation of the Co nano particles are reduced, and the uniformly dispersed Co nano particles and an adjacent active nitrogen structure form Co-N better x Active sites as active catalytic centers for oxygen evolution reactions in porous carbon sphere matrices and highly dispersed Co-N x Under the synergistic action of the catalytic active centers, the oxygen evolution reaction catalyst shows high oxygen evolution initial potential and oxygen evolutionOxygen half-wave potential, and has excellent catalytic activity of oxygen evolution reaction.)

1. A Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst is characterized in that: the preparation method of the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst comprises the following steps:

(1) preparing lignin spherical porous beads by an inverse suspension polymerization technology;

(2) adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding aqueous solution of hydrogen peroxide and ferrous sulfate at 50-70 ℃, and stirring for reaction for 2-4h to prepare acrylonitrile modified lignin microspheres;

(3) adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, uniformly stirring, heating to 60-80 ℃, adding acrylonitrile modified lignin microspheres, and stirring for reaction for 3-8 hours to obtain amidoxime lignin microspheres;

(4) adding deionized water, a cobalt source and amidoximated lignin microspheres into a conical flask, stirring at a constant speed for 24-48h, and performing an adsorption process to obtain Co modified lignin microspheres;

(5) and (3) putting the Co modified lignin microspheres into an atmosphere furnace for carbonization to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

2. The catalyst for the oxygen evolution reaction of the Co-N double-doped biomass porous carbon spheres as claimed in claim 1, wherein: the mass ratio of the lignin spherical porous beads, the acrylonitrile, the hydrogen peroxide and the ferrous sulfate in the step (2) is 100:80-160:2-3.5: 220-400.

3. The catalyst for the oxygen evolution reaction of the Co-N double-doped biomass porous carbon spheres as claimed in claim 1, wherein: the mass ratio of the hydroxylamine hydrochloride, the sodium carbonate and the acrylonitrile modified lignin microspheres in the step (3) is 15-30:8-15: 100.

4. The catalyst for the oxygen evolution reaction of the Co-N double-doped biomass porous carbon spheres as claimed in claim 1, wherein: the cobalt source in the step (4) is any one of cobalt chloride, cobalt sulfate, cobalt nitrate or cobalt acetate, and the mass ratio of the cobalt source to the amidoxime lignin microspheres is 30-80: 100.

5. The catalyst for the oxygen evolution reaction of the Co-N double-doped biomass porous carbon spheres as claimed in claim 1, wherein: the carbonization process in the step (5) is a nitrogen atmosphere, the carbonization temperature is 750-850 ℃, and the carbonization time is 2-3 h.

Technical Field

The invention relates to the field of zinc-air batteries, in particular to a Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst and a preparation method thereof.

Background

The zinc-air battery has the characteristics of small volume, light weight, large charge capacity, wide working temperature range, environmental protection, no pollution and the like, is considered to be an ideal power source for equipping electric automobiles and the like, and is one of the most promising energy conversion devices, wherein the discharging process of the zinc-air battery corresponds to an Oxygen Reduction Reaction (ORR), and the charging process corresponds to an Oxygen Evolution Reaction (OER), but the oxygen evolution reaction is slow in dynamics, and generally needs to be driven to be carried out by adding a high-efficiency catalyst, and the catalyst is mainly an expensive platinum-based noble metal catalyst, so that the development of the oxygen evolution reaction catalyst with high catalytic activity and low cost becomes a research hotspot.

The porous carbon material has rich mesoporous structure,The porous carbon material has the advantages of ultrahigh specific surface area, good electrochemical property, low price and easy obtainment, and has wide research and application in the electrochemical fields of super capacitors, fuel cells, lithium ion batteries and the like, and Co-N is introduced into the porous carbon material at present_x、Ni-N_xThe catalytic active sites of the equal oxygen evolution reaction can enable the porous carbon material to show good oxygen evolution activity, and the method is an effective strategy for developing a novel non-noble metal oxygen evolution catalyst.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst and a preparation method thereof, and the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst is rich in Co-N_xOxygen evolution catalytic sites and excellent oxygen evolution activity.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: an oxygen evolution reaction catalyst of Co-N double-doped biomass porous carbon spheres comprises the following components: the preparation method of the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst comprises the following steps:

(1) the lignin spherical porous beads are prepared by the reversed phase suspension polymerization technology.

(2) Adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding aqueous solution of hydrogen peroxide and ferrous sulfate at 50-70 ℃, stirring for reaction for 2-4h, centrifugally washing by using deionized water and ethanol, and drying to obtain the acrylonitrile modified lignin microspheres.

(3) Adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, uniformly stirring, heating to 60-80 ℃, adding acrylonitrile modified lignin microspheres, stirring for reaction for 3-8h, centrifugally washing by using deionized water and ethanol, and drying to obtain the amidoxime lignin microspheres.

(4) And adding deionized water, a cobalt source and the amidoximated lignin microspheres into a conical flask, stirring at a constant speed for 24-48h, performing an adsorption process, and performing vacuum drying to remove water to obtain the Co modified lignin microspheres.

(5) And (3) putting the Co modified lignin microspheres into an atmosphere furnace for carbonization to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

Preferably, the mass ratio of the lignin spherical porous beads, the acrylonitrile, the hydrogen peroxide and the ferrous sulfate in the step (2) is 100:80-160:2-3.5: 220-400.

Preferably, the mass ratio of the hydroxylamine hydrochloride, the sodium carbonate and the acrylonitrile modified lignin microspheres in the step (3) is 15-30:8-15: 100.

Preferably, the cobalt source in the step (4) is any one of cobalt chloride, cobalt sulfate, cobalt nitrate or cobalt acetate, and the mass ratio of the cobalt source to the amidoximated lignin microspheres is 30-80: 100.

Preferably, the carbonization process in the step (5) is a nitrogen atmosphere, the carbonization temperature is 750-850 ℃, and the carbonization time is 2-3 h.

(III) advantageous technical effects

Compared with the prior art, the invention has the following chemical mechanism and beneficial technical effects:

the oxygen evolution reaction catalyst of the Co-N double-doped biomass porous carbon sphere is prepared from Fe²⁺/H₂O₂In the initiation system, the alkenyl of acrylonitrile reacts with lignin microspheres to obtain acrylonitrile modified lignin microspheres, so that a large amount of cyano functional groups are introduced into the matrix of the lignin microspheres, and then the cyano groups and hydroxylamine hydrochloride undergo amidoximation reaction to obtain lignin microspheres containing rich amidoxime functional groups, wherein the amidoxime functional groups are Co pairs²⁺The ions have strong complexation adsorption and chelation coordination effects, so that Co is adsorbed²⁺Uniformly adsorbing into the matrix of lignin microspheres to make Co²⁺The height is distributed in the lignin microspheres.

According to the oxygen evolution reaction catalyst of the Co-N double-doped biomass porous carbon spheres, in the high-temperature carbonization process, the cheap and easily-obtained lignin microspheres are used as a biomass carbon source, the amidoxime functional groups are used as a nitrogen source, the carbonization is carried out to obtain the N-doped porous carbon spheres, the N-doped porous carbon spheres have rich mesoporous structures and ultrahigh specific surface areas, the N doping mainly adopts graphite nitrogen, pyridine nitrogen and pyrrole nitrogen structures, the electrochemical properties of the porous carbon spheres can be adjusted, the conductivity is improved, the transfer of electrons in the oxygen evolution reaction process is promoted, and the amidoxime functional groups are adsorbedCo of (A)²⁺Thermal reduction to form Co nanoparticles due to Co²⁺Is uniformly adsorbed into the matrix of the lignin microspheres, so that the Co nano particles subjected to thermal reduction are highly dispersed in the matrix of the N-doped porous carbon spheres, the agglomeration and aggregation of the Co nano particles are reduced, and the uniformly dispersed Co nano particles and an adjacent active nitrogen structure form Co-N better_xActive sites as active catalytic centers for oxygen evolution reactions in porous carbon sphere matrices and highly dispersed Co-N_xUnder the synergistic action of the catalytic active center, the oxygen evolution reaction catalyst shows high oxygen evolution initial potential and oxygen evolution half-wave potential, and has excellent catalytic activity of the oxygen evolution reaction.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: a Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst is prepared by the following steps:

(1) the lignin spherical porous beads are prepared by the reversed phase suspension polymerization technology.

(2) Adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding aqueous solution of hydrogen peroxide and ferrous sulfate at 50-70 ℃, stirring for reaction for 2-4h, centrifugally washing by using deionized water and ethanol, and drying to obtain the acrylonitrile modified lignin microspheres, wherein the mass ratio of the lignin spherical porous beads to the acrylonitrile to the hydrogen peroxide to the ferrous sulfate is 100:80-160:2-3.5: 220-400.

(3) Adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, uniformly stirring, heating to 60-80 ℃, adding acrylonitrile modified lignin microspheres, wherein the mass ratio of the hydroxylamine hydrochloride to the sodium carbonate to the acrylonitrile modified lignin microspheres is 15-30:8-15:100, stirring for reaction for 3-8h, centrifugally washing with the deionized water and ethanol, and drying to obtain the amidoxime lignin microspheres.

(4) Adding deionized water, a cobalt source and the amidoximated lignin microspheres in a mass ratio of 30-80:100 into a conical flask, wherein the cobalt source is any one of cobalt chloride, cobalt sulfate, cobalt nitrate or cobalt acetate, stirring at a constant speed for 24-48h, performing an adsorption process, and performing vacuum drying to remove moisture to obtain the Co modified lignin microspheres.

(5) And (3) placing the Co modified lignin microspheres in an atmosphere furnace, and carbonizing at the temperature of 750-850 ℃ for 2-3h in the nitrogen atmosphere to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

Example 1

(1) The lignin spherical porous beads are prepared by the reversed phase suspension polymerization technology.

(2) Adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding aqueous solution of hydrogen peroxide and ferrous sulfate at 50 ℃, stirring for reaction for 2 hours, centrifugally washing by using deionized water and ethanol, and drying to obtain the acrylonitrile modified lignin microspheres, wherein the mass ratio of the lignin spherical porous beads to the acrylonitrile to the hydrogen peroxide to the ferrous sulfate is 100:80:2: 220.

(3) Adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, stirring uniformly, heating to 60 ℃, adding acrylonitrile modified lignin microspheres, wherein the mass ratio of the hydroxylamine hydrochloride to the sodium carbonate to the acrylonitrile modified lignin microspheres is 15:8:100, stirring for reaction for 3 hours, centrifugally washing by using the deionized water and ethanol, and drying to obtain the amidoxime lignin microspheres.

(4) Adding deionized water, cobalt chloride and amidoximated lignin microspheres in a mass ratio of 30:100 into a conical flask, stirring at a constant speed for 24 hours, performing an adsorption process, and performing vacuum drying to remove water to obtain the Co modified lignin microspheres.

(5) And (3) placing the Co modified lignin microspheres in an atmosphere furnace, and carbonizing for 2h at 750 ℃ in a nitrogen atmosphere to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

Example 2

(1) The lignin spherical porous beads are prepared by the reversed phase suspension polymerization technology.

(2) Adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding aqueous solution of hydrogen peroxide and ferrous sulfate at 70 ℃, stirring for reaction for 3 hours, centrifugally washing by using deionized water and ethanol, and drying to obtain the acrylonitrile modified lignin microspheres, wherein the mass ratio of the lignin spherical porous beads to the acrylonitrile to the hydrogen peroxide to the ferrous sulfate is 100:100:2.5: 280.

(3) Adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, stirring uniformly, heating to 80 ℃, adding acrylonitrile modified lignin microspheres, wherein the mass ratio of the hydroxylamine hydrochloride to the sodium carbonate to the acrylonitrile modified lignin microspheres is 22:12:100, stirring for reaction for 5 hours, centrifugally washing by using the deionized water and ethanol, and drying to obtain the amidoxime lignin microspheres.

(4) Adding deionized water, cobalt nitrate and amidoximated lignin microspheres in a mass ratio of 50:100 into a conical flask, stirring at a constant speed for 36 hours, performing an adsorption process, and performing vacuum drying to remove water to obtain the Co modified lignin microspheres.

(5) Placing the Co modified lignin microspheres in an atmosphere furnace, and carbonizing for 3h at 800 ℃ in a nitrogen atmosphere to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

Example 3

(1) The lignin spherical porous beads are prepared by the reversed phase suspension polymerization technology.

(2) Adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding an aqueous solution of hydrogen peroxide and ferrous sulfate at the temperature of 60 ℃, stirring for reaction for 3 hours, centrifugally washing by using deionized water and ethanol, and drying to obtain the acrylonitrile modified lignin microspheres.

(3) Adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, stirring uniformly, heating to 80 ℃, adding acrylonitrile modified lignin microspheres, wherein the mass ratio of the hydroxylamine hydrochloride to the sodium carbonate to the acrylonitrile modified lignin microspheres is 25:10:100, stirring for reaction for 5 hours, centrifugally washing by using the deionized water and ethanol, and drying to obtain the amidoxime lignin microspheres.

(4) Adding deionized water, cobalt acetate and amidoximated lignin microspheres in a mass ratio of 70:100 into a conical flask, stirring at a constant speed for 36 hours, performing an adsorption process, and performing vacuum drying to remove water to obtain the Co modified lignin microspheres.

(5) Placing the Co modified lignin microspheres in an atmosphere furnace, and carbonizing for 3h at 850 ℃ in a nitrogen atmosphere to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

Example 4

(1) The lignin spherical porous beads are prepared by the reversed phase suspension polymerization technology.

(2) Adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding aqueous solution of hydrogen peroxide and ferrous sulfate at 60 ℃, stirring for reaction for 4 hours, centrifugally washing by using deionized water and ethanol, and drying to obtain the acrylonitrile modified lignin microspheres.

(3) Adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, stirring uniformly, heating to 60 ℃, adding acrylonitrile modified lignin microspheres, wherein the mass ratio of the hydroxylamine hydrochloride to the sodium carbonate to the acrylonitrile modified lignin microspheres is 30:15:100, stirring for reacting for 8 hours, centrifugally washing by using the deionized water and ethanol, and drying to obtain the amidoxime lignin microspheres.

(4) Adding deionized water, cobalt sulfate and amidoximated lignin microspheres in a mass ratio of 80:100 into a conical flask, stirring at a constant speed for 48 hours, performing an adsorption process, and performing vacuum drying to remove water to obtain the Co modified lignin microspheres.

(5) And (3) placing the Co modified lignin microspheres in an atmosphere furnace, and carbonizing for 2h at 850 ℃ in a nitrogen atmosphere to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

Comparative example 1

(1) The lignin spherical porous beads are prepared by the reversed phase suspension polymerization technology.

(2) Adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding aqueous solution of hydrogen peroxide and ferrous sulfate at 70 ℃, stirring for reaction for 4 hours, centrifugally washing by using deionized water and ethanol, and drying to obtain the acrylonitrile modified lignin microspheres, wherein the mass ratio of the lignin spherical porous beads to the acrylonitrile to the hydrogen peroxide to the ferrous sulfate is 100:50:1.5: 160.

(3) Adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, stirring uniformly, heating to 60 ℃, adding acrylonitrile modified lignin microspheres, wherein the mass ratio of the hydroxylamine hydrochloride to the sodium carbonate to the acrylonitrile modified lignin microspheres is 10:5:100, stirring for reacting for 8 hours, centrifugally washing by using the deionized water and ethanol, and drying to obtain the amidoxime lignin microspheres.

(4) Adding deionized water, cobalt nitrate and amidoximated lignin microspheres in a mass ratio of 15:100 into a conical flask, stirring at a constant speed for 48 hours, performing an adsorption process, and performing vacuum drying to remove water to obtain the Co modified lignin microspheres.

(5) And (3) placing the Co modified lignin microspheres in an atmosphere furnace, and carbonizing for 2h at 750 ℃ in a nitrogen atmosphere to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

Comparative example 2

(1) The lignin spherical porous beads are prepared by the reversed phase suspension polymerization technology.

(2) Adding deionized water and lignin spherical porous beads into a conical flask, adding acrylonitrile after uniform ultrasonic dispersion, adding aqueous solution of hydrogen peroxide and ferrous sulfate at 70 ℃, stirring for reaction for 3 hours, centrifugally washing by using deionized water and ethanol, and drying to obtain the acrylonitrile modified lignin microspheres, wherein the mass ratio of the lignin spherical porous beads to the acrylonitrile to the hydrogen peroxide to the ferrous sulfate is 100:200:4: 450.

(3) Adding deionized water, hydroxylamine hydrochloride and sodium carbonate into a conical flask, stirring uniformly, heating to 80 ℃, adding acrylonitrile modified lignin microspheres, wherein the mass ratio of the hydroxylamine hydrochloride to the sodium carbonate to the acrylonitrile modified lignin microspheres is 35:20:100, stirring for reaction for 3 hours, centrifugally washing by using the deionized water and ethanol, and drying to obtain the amidoxime lignin microspheres.

(4) Adding deionized water, cobalt chloride and amidoximated lignin microspheres in a mass ratio of 1:1 into a conical flask, stirring at a constant speed for 36 hours, performing an adsorption process, and performing vacuum drying to remove water to obtain the Co modified lignin microspheres.

(5) Placing the Co modified lignin microspheres in an atmosphere furnace, and carbonizing for 3h at 750 ℃ in a nitrogen atmosphere to obtain the Co-N double-doped biomass porous carbon sphere oxygen evolution reaction catalyst.

Preparing an oxygen evolution catalyst electrode material: dispersing the oxygen evolution reaction catalyst of the Co-N double-doped biomass porous carbon spheres in an isopropanol solvent, adding a Nafion solution, performing ultrasonic dispersion, coating the solution on a disc electrode, and drying to obtain the oxygen evolution catalyst electrode material.

And (3) electrochemical performance testing: the electrochemical performance and oxygen evolution activity of the oxygen evolution catalyst electrode material are tested in an Autolab PGSTAT302N electrochemical workstation by taking Ag/AgCl as a reference electrode, a Pt electrode as a counter electrode and 0.1mol/L KOH solution as electrolyte, and the test standard is GB/T18333.2-2015.