阅读说明：本技术 一种基于双致孔剂合成的多级孔氮掺杂碳催化剂的普适性制备方法及其应用 (Universal preparation method and application of hierarchical pore nitrogen-doped carbon catalyst based on double-pore-foaming agent synthesis ) 是由 高书燕 王新宇 田苗 陈野 于 2019-11-13 设计创作，主要内容包括：本发明公开了一种基于双致孔剂合成的多级孔氮掺杂碳催化剂的普适性制备方法及其应用。将生物质壳聚糖、乙二胺四乙酸二钠钴盐和分子筛SBA-15用水混合后烘干得到物料A；将物料A在惰性气体保护下由室温经过60min升温至300℃保持60min,再以10℃/min的升温速率升温至800℃保持120min,自然降温至室温得到物料B；将物料B加入酸性溶液浸泡12h,再用高纯水洗涤至滤液为中性,于40-60℃干燥12h得到目标产物多级孔氮掺杂碳催化剂。本发明制得的多级孔氮掺杂碳催化剂的比表面积为661-925m2/g,且含有大量的微孔和介孔,将其作为阴极材料应用到电芬顿体系中,能够高效降解有机污染物,且在使用的过程中不会造成二次污染,对环境友好。(The invention discloses a universal preparation method and application of a hierarchical pore nitrogen-doped carbon catalyst based on double pore-foaming agent synthesis. Mixing the biomass chitosan, ethylene diamine tetraacetic acid disodium cobalt salt and a molecular sieve SBA-15 with water, and drying to obtain a material A; heating the material A from room temperature to 300 ℃ for 60min under the protection of inert gas, then heating to 800 ℃ at the heating rate of 10 ℃/min for 120min, and naturally cooling to room temperature to obtain a material B; and adding the material B into an acid solution, soaking for 12h, washing with high-purity water until the filtrate is neutral, and drying at 40-60 ℃ for 12h to obtain the target product, namely the hierarchical porous nitrogen-doped carbon catalyst. The specific surface area of the multi-level pore nitrogen-doped carbon catalyst prepared by the invention is 661-925m2/g, and the catalyst contains a large number of micropores and mesopores, and the catalyst can be used as a cathode material to be applied to an electro-Fenton system, can efficiently degrade organic pollutants, does not cause secondary pollution in the using process, and is environment-friendly.)

1. A universal preparation method of a hierarchical pore nitrogen-doped carbon catalyst based on double pore-foaming agent synthesis is characterized by comprising the following specific steps:

step S1: mixing the biomass chitosan, ethylene diamine tetraacetic acid disodium cobalt salt (EDTA-2 Na-Co) and molecular sieve SBA-15 with water, stirring for 2 hours by using a magnetic stirrer, fully mixing uniformly, and drying to obtain a material A;

step S2: transferring the material A obtained in the step S1 to a nickel boat, placing the nickel boat in a tube furnace, raising the temperature from room temperature to 300 ℃ for 60min after 60min under the protection of inert gas, raising the temperature to 800 ℃ at a heating rate of 10 ℃/min for 120min, and naturally cooling to room temperature to obtain a material B;

step S3: will step withTransferring the material B obtained in the step S2 to a container, adding an acid solution to soak for 12h, washing with high-purity water until the filtrate is neutral, and drying at 40-60 ℃ for 12h to obtain the target product, namely the hierarchical porous nitrogen-doped carbon catalyst, wherein the specific surface area of the hierarchical porous nitrogen-doped carbon catalyst is 661-925m ²And/g, and contains a large number of micropores and mesopores.

2. The universal preparation method of the hierarchical pore nitrogen-doped carbon catalyst based on double-pore-foaming agent synthesis, according to claim 1, is characterized in that: the feeding mass ratio of the biomass chitosan, the ethylene diamine tetraacetic acid disodium cobalt salt and the molecular sieve SBA-15 is 1:0.5-3.5: 0.5-3.5.

3. The universal preparation method of the hierarchical pore nitrogen-doped carbon catalyst based on double-pore-foaming agent synthesis, according to claim 1, is characterized in that: the feeding mass ratio of the biomass chitosan to the ethylene diamine tetraacetic acid disodium cobalt salt to the molecular sieve SBA-15 is 1:2.5: 2.5.

4. The universal preparation method of the hierarchical pore nitrogen-doped carbon catalyst based on double-pore-foaming agent synthesis, according to claim 1, is characterized in that: the inert gas is one or more of nitrogen or argon.

5. The universal preparation method of the hierarchical pore nitrogen-doped carbon catalyst based on double-pore-foaming agent synthesis, according to claim 1, is characterized in that: the acid solution is a 10wt% hydrofluoric acid solution.

6. The universal preparation method of the hierarchical pore nitrogen-doped carbon catalyst based on double-pore-foaming agent synthesis according to claim 1, which is characterized by comprising the following specific steps:

step S1: mixing 1g of biomass chitosan, 2.5g of EDTA-2Na-Co and 2.5g of molecular sieve SBA-15 with water, stirring for 2 hours by using a magnetic stirrer, fully mixing uniformly, and drying to obtain a material A;

step S2: transferring the material A obtained in the step S1 to a nickel boat, placing the nickel boat in a tube furnace, heating the material A to 300 ℃ from room temperature for 60min under the protection of nitrogen gas with the flow rate of 100mL/min, keeping the temperature for 60min, heating the material A to 800 ℃ at the heating rate of 10 ℃/min, keeping the temperature for 120min, and naturally cooling the material A to room temperature to obtain a material B;

step S3: and (4) transferring the material B obtained in the step S2 to a 100mL beaker, adding an acidic solution to soak for 12h, washing with high-purity water until the filtrate is neutral, and drying at 40 ℃ for 12h in a forced air drying oven to obtain the multi-stage pore nitrogen-doped carbon catalyst C, wherein the multi-stage pore nitrogen-doped carbon catalyst C is used as a cathode material of an electro-Fenton system and is used for degrading 50mL of 15mg/L malachite green solution, and the time for complete degradation is 60 min.

7. The hierarchical porous nitrogen-doped carbon catalyst prepared by the method according to any one of claims 1 to 6 is used as a cathode material in an electro-Fenton system for efficiently degrading organic pollutants in water.

Technical Field

The invention belongs to the technical field of synthesis of porous carbon materials, and particularly relates to a universal preparation method and application of a hierarchical pore nitrogen-doped carbon catalyst synthesized based on a double pore-foaming agent.

Background

Energy crisis and environmental pollution are two major problems of global nature, hinder the development of social aspects. With the development of science and technology, the quantity of artificially synthesized refractory organic matters is increased. Meanwhile, in the industrial production process, organic pollutants which have high biotoxicity and are extremely difficult to be degraded by microorganisms are also discharged into rivers, soil and other natural world, which seriously harms the living environment of people and animals and plants. Therefore, the treatment problem of refractory organic pollutants is receiving more and more attention.

The electro-Fenton process uses an oxygen reduction process to generate hydrogen peroxide in situ at the cathode, followed by H ₂O ₂With Fe ²⁺The Fenton reaction is carried out to generate a strong oxidant, namely OH, which can attack organic pollutants without selectivity to degrade the organic pollutants into carbon dioxide and water, thereby achieving the purposes of degrading the pollutants and purifying the water quality. Compared with other oxidation technologies, the electro-Fenton technology has the advantages of low cost, mild reaction conditions, high treatment speed, simple reaction device, thorough degradation, no secondary pollutants and the like, and is a novel, efficient and environment-friendly advanced electrochemical oxidation technology. In order to expose more active sites in the catalytic material and thus improve its catalytic performance, a templating agent is often added. Commonly used templating agents include hard and soft template porogens. The molecular sieve SBA-15 serving as a traditional hard template pore-foaming agent can construct a highly ordered, uniform and well-dispersed pore structure on the surface of a carbon material, but the preparation cost of the pore-foaming agent is high. In order to compensate for the above-mentioned drawbacks, researchers have also tried to prepare porous carbon materials using a soft template method. Among many soft template agents, disodium ethylene diamine tetraacetate cobalt salt is widely applied due to the characteristics of adjustable pore-forming size, more defect sites and low price, but the synthesized carbon material has poor orderliness and nonuniform distribution. Based on the above, the invention uses ethylenediamineThe disodium tetraethyl cobalt tetraacetate (EDTA-2 Na-Co) and the molecular sieve SBA-15 are combined to prepare the cathode material for the electro-Fenton system, which has the advantages of highly ordered pore structure, adjustable pore size and low cost.

Disclosure of Invention

The invention solves the technical problem of providing a universal preparation method and application of a hierarchical pore nitrogen-doped carbon catalyst synthesized based on double pore-forming agents, wherein the hierarchical pore nitrogen-doped carbon catalyst has an ordered pore structure and adjustable pore size, is low in cost and is environment-friendly.

The invention adopts the following technical scheme for solving the technical problems, and the universal preparation method of the hierarchical pore nitrogen-doped carbon catalyst based on double pore-foaming agent synthesis is characterized by comprising the following specific processes:

step S1: mixing the biomass chitosan, ethylene diamine tetraacetic acid disodium cobalt salt (EDTA-2 Na-Co) and molecular sieve SBA-15 with water, stirring for 2 hours by using a magnetic stirrer, fully mixing uniformly, and drying to obtain a material A;

step S2: transferring the material A obtained in the step S1 to a nickel boat, placing the nickel boat in a tube furnace, raising the temperature from room temperature to 300 ℃ for 60min after 60min under the protection of inert gas, raising the temperature to 800 ℃ at a heating rate of 10 ℃/min for 120min, and naturally cooling to room temperature to obtain a material B;

step S3: transferring the material B obtained in the step S2 into a container, adding an acid solution to soak for 12h, washing with high-purity water until the filtrate is neutral, and drying at 40-60 ℃ for 12h to obtain the target product, namely the hierarchical porous nitrogen-doped carbon catalyst, wherein the specific surface area of the hierarchical porous nitrogen-doped carbon catalyst is 661-925m ²And/g, and contains a large number of micropores and mesopores.

Further preferably, the feeding mass ratio of the biomass chitosan, the ethylene diamine tetraacetic acid disodium cobalt salt and the molecular sieve SBA-15 is 1:0.5-3.5: 0.5-3.5.

Further preferably, the feeding mass ratio of the biomass chitosan, the ethylene diamine tetraacetic acid disodium cobalt salt and the molecular sieve SBA-15 is 1:2.5: 2.5.

Further preferably, the inert gas is one or more of nitrogen or argon.

More preferably, the acidic solution is a 10wt% hydrofluoric acid solution.

Further preferably, the universal preparation method of the hierarchical pore nitrogen-doped carbon catalyst based on double-pore-foaming agent synthesis is characterized by comprising the following specific steps:

step S1: mixing 1g of biomass chitosan, 2.5g of EDTA-2Na-Co and 2.5g of molecular sieve SBA-15 with water, stirring for 2 hours by using a magnetic stirrer, fully mixing uniformly, and drying to obtain a material A;

step S2: transferring the material A obtained in the step S1 to a nickel boat, placing the nickel boat in a tube furnace, heating the material A to 300 ℃ from room temperature for 60min under the protection of nitrogen gas with the flow rate of 100mL/min, keeping the temperature for 60min, heating the material A to 800 ℃ at the heating rate of 10 ℃/min, keeping the temperature for 120min, and naturally cooling the material A to room temperature to obtain a material B;

step S3: and (4) transferring the material B obtained in the step S2 to a 100mL beaker, adding an acidic solution to soak for 12h, washing with high-purity water until the filtrate is neutral, and drying at 40 ℃ for 12h in a forced air drying oven to obtain the multi-stage pore nitrogen-doped carbon catalyst C, wherein the multi-stage pore nitrogen-doped carbon catalyst C is used as a cathode material of an electro-Fenton system and is used for degrading 50mL of 15mg/L malachite green solution, and the time for complete degradation is 60 min.

The hierarchical pore nitrogen-doped carbon catalyst is used as a cathode material in an electro-Fenton system for efficiently degrading organic pollutants in a water body.

Compared with the prior art, the invention has the following beneficial effects:

1. the preparation method simultaneously introduces ethylene diamine tetraacetic acid disodium cobalt salt (EDTA-2 Na-Co) and the molecular sieve SBA-15 as template agents, wherein the molecular sieve SBA-15 solid is used as a pore-forming agent, and a highly ordered, uniform and well-dispersed pore structure can be manufactured on the surface of a carbon material; the ethylene diamine tetraacetic acid disodium cobalt salt (EDTA-2 Na-Co) solid is used as a pore-forming agent, so that a large number of micropores and mesopores can be generated in the carbon material, the specific surface area and pore volume of the carbon material are increased, more active sites are exposed, the catalytic degradation activity of the material is enhanced, and the preparation process of the multilevel pore nitrogen-doped carbon catalyst is simple and has strong universality;

2. the specific surface area of the hierarchical porous nitrogen-doped carbon catalyst prepared by the method is 661-925m ²The cathode material is used as a cathode material applied to an electro-Fenton system, can efficiently degrade organic pollutants, does not cause secondary pollution in the using process, and is environment-friendly.

Drawings

FIG. 1 is a field emission scanning electron micrograph of a multi-level pore nitrogen-doped carbon catalyst prepared according to example 4;

FIG. 2 is an X-ray diffraction pattern of the carbon catalysts prepared in examples 1-4;

FIG. 3 is a graph of nitrogen desorption and pore size distribution of the multi-level pore nitrogen-doped carbon catalyst prepared in example 4;

FIG. 4 is a Raman spectrum of the carbon catalysts prepared in examples 1-4;

fig. 5 is a graph showing the time period for degradation of malachite green by the carbon catalysts prepared in examples 1-6.

Detailed Description

The present invention is described in further detail below with reference to examples, but it should not be construed that the scope of the above subject matter of the present invention is limited to the following examples, and that all the technologies realized based on the above subject matter of the present invention belong to the scope of the present invention.