阅读说明：本技术 一种负载型钯镍双金属纳米合金催化材料及其制备方法 (Supported palladium-nickel bimetallic nano-alloy catalytic material and preparation method thereof ) 是由 张泽武 史皓峻 杨云峰 于 2019-01-16 设计创作，主要内容包括：本发明公开了一种负载型钯镍双金属纳米合金催化材料,所述材料的载体为蛋黄-蛋壳型复合物,其中载体的内核为磁性纳米铁颗粒,载体的外壳为经4,4′-二氨基联苯和均三羟基苯交联碳化后得到的氮掺杂碳多面体,所述催化材料的活性负载物为钯镍双金属纳米合金。该催化材料具有较高的催化反应活性和稳定性,在生物制药、化学工业、汽车尾气处理、污水处理等领域有较大的应用前景。(The invention discloses a supported palladium-nickel bimetallic nano-alloy catalytic material, wherein a carrier of the material is a yolk-eggshell type compound, an inner core of the carrier is magnetic nano-iron particles, an outer shell of the carrier is a nitrogen-doped carbon polyhedron obtained by crosslinking and carbonizing 4, 4' -diaminobiphenyl and trihydroxy benzene, and an active load of the catalytic material is palladium-nickel bimetallic nano-alloy. The catalytic material has high catalytic reaction activity and stability, and has wide application prospect in the fields of biological pharmacy, chemical industry, automobile exhaust treatment, sewage treatment and the like.)

1. A supported palladium-nickel bimetallic nano-alloy catalytic material is characterized in that a carrier of the catalytic material is a yolk-eggshell type compound, wherein the inner core of the carrier is magnetic nano-iron particles, the shell of the carrier is a nitrogen-doped carbon polyhedron, and an active load is palladium-nickel bimetallic nano-alloy particles.

2. The supported palladium-nickel bimetallic nano-alloy catalytic material as claimed in claim 1, wherein the nitrogen-doped carbon polyhedron is obtained by high-temperature carbonization of a covalent organic framework polymer formed by crosslinking 4, 4' -diaminobiphenyl and trihydroxy benzene.

3. The supported palladium-nickel bimetallic nano-alloy catalytic material as claimed in claim 1, wherein the size of the magnetic nano-iron particles is 10-50 nm, the thickness of the nitrogen-doped carbon polyhedron is 30-100 nm, and the size of the palladium-nickel bimetallic nano-alloy particles is 1-10 nm.

4. A preparation method of a supported palladium-nickel bimetallic nano-alloy catalytic material is characterized by comprising the following steps:

a) preparing 0.2-0.8% of ferric chloride aqueous solution at room temperature, adding 0.002-0.01% of potassium dihydrogen phosphate aqueous solution according to the mass ratio of 0.005: 1-0.05: 1 of potassium dihydrogen phosphate to ferric chloride, stirring for reaction for 30-60 min, transferring into a reaction kettle, reacting for 36-72 h at 80-120 ℃, centrifugally separating, washing precipitate with 100-500 times of deionized water based on the mass of ferric chloride, and vacuum drying for 8-12 h at 70-100 ℃ to obtain Fe₂O₃A nanoparticle;

b) preparing a hydrochloric acid solution with the mass fraction of 0.1-0.4% at room temperature, adding 4, 4 '-diaminobiphenyl according to the mass ratio of 0.001: 1-0.004: 1 of the 4, 4' -diaminobiphenyl to the hydrochloric acid solution, adding a sodium nitrite solution with the mass fraction of 0.5-1.0% according to the mass ratio of 0.2: 1-0.4: 1 of the sodium nitrite solution to the hydrochloric acid solution, uniformly mixing and stirring at 0-4 ℃, and adjusting the pH of the mixed solution to 6-8 by using an inorganic alkaline water solution with the mass fraction of 10-50% to obtain an aminobiphenyl mixed solution;

c) preparing 0.5-5% sodium carbonate aqueous solution at room temperature according to the weight percentage of Fe₂O₃Adding the Fe prepared in the step a) into the nano particles and sodium carbonate at a mass ratio of 0.2: 1-1: 1₂O₃Nanoparticles of trihydroxybenzene and Fe₂O₃Adding trihydroxy benzene into the nano particles according to the mass ratio of 0.2: 1-1: 1, mixing and stirring for 30-60 min at 0-4 ℃ to obtain trihydroxy benzene mixed solution, adding the aminobiphenyl mixed solution prepared in the step b) into the trihydroxy benzene mixed solution according to the mass ratio of 1: 1-5: 1 of aminobiphenyl mixed solution and trihydroxy benzene mixed solution, stirring and reacting for 10-15 h at 0-4 ℃, performing centrifugal separation, and sequentially using 100-500 times of Fe₂O₃Washing and precipitating with deionized water and ethanol with the mass of nano particles, and drying in vacuum at 60-80 ℃ for 10-12 h to obtain Fe₂O₃-a covalent organic framework polymer core-shell complex;

d) according to Fe₂O₃The mass ratio of the covalent organic framework polymer core-shell compound to the deionized water is 0.01: 1-0.1: 1, and the Fe prepared in the step c) is added₂O₃-covalent organic framework polymer core-shell complexes dispersed in deionized water as palladium source with Fe₂O₃Adding a palladium source into the covalent organic framework polymer core-shell composite according to the mass ratio of 0.01: 1-0.1: 1, adding a nickel source into the covalent organic framework polymer core-shell composite according to the mass ratio of 0.2: 1-2: 1 of the nickel source and the palladium source, ultrasonically dispersing for 30-60 min, adjusting the pH of the solution to 10-14 by using a sodium hydroxide aqueous solution with the mass fraction of 0.1-1%, stirring and reacting for 2-8 h, centrifugally separating, precipitating and using 50-500 times of Fe₂O₃Washing the covalent organic framework polymer core-shell composite with deionized water, and drying the washed covalent organic framework polymer core-shell composite for 8 to 12 hours at the temperature of between 60 and 80 ℃ in vacuum to obtain Fe₂O₃-a covalent organic framework polymer/Pd-Ni alloy composite;

e) subjecting the Fe obtained in step d)₂O₃Placing the covalent organic framework polymer/Pd-Ni alloy composite material in a tubular furnace, introducing reducing gas, adjusting the gas flow to 0.2-3 m L/min, reducing for 2-6 h at 600-800 ℃, and cooling to room temperature to obtain the supported palladium-nickel bimetallic nano alloy catalytic material.

5. The method for preparing a supported palladium-nickel bimetallic nano-alloy catalytic material as claimed in claim 4, wherein the inorganic base in step b) is one of sodium hydroxide, sodium carbonate and sodium bicarbonate.

6. The method for preparing a supported palladium-nickel bimetallic nano-alloy catalytic material as claimed in claim 4, wherein the palladium source in step d) is one of palladium chloride and palladium acetate, and the nickel source is one of nickel nitrate, nickel acetate and nickel chloride.

7. The preparation method of the supported palladium-nickel bimetallic nano-alloy catalytic material as claimed in claim 4, wherein the reducing gas in the step e) is a hydrogen-helium mixed gas with a volume ratio of 1: 5-1: 10.

The technical field is as follows:

the invention relates to a supported palladium-nickel bimetallic nano-alloy catalytic material and a preparation method thereof, belonging to the field of heterogeneous catalytic materials.

Technical background:

the nano noble metal catalytic material shows high catalytic activity in reactions such as selective reduction of nitro compounds, CO oxidation and the like, and is widely concerned by people. Particularly, some cheap non-noble metals are added into noble metal nano particles to form the bimetallic nano alloy catalytic material, so that the catalytic activity of the catalytic material can be further improved, and the cost of the catalytic material is reduced.

Chinese patent application No. 201711377594.8 discloses a method for preparing a platinum-nickel alloy catalyst, which comprises reacting carbon-supported metallic nickel nanoparticles with chloroplatinic acid to obtain the platinum-nickel alloy catalyst. The chinese patent with application number 201610601513.7 discloses a preparation method of a carbon quantum dot/graphene-supported PtM alloy catalyst, wherein M is one of Fe, Co, Ni, Cu, Mn or Sn, the catalytic material exhibits better catalytic performance, and has better catalytic activity and economic value compared with the conventional single noble metal catalytic material. Therefore, the preparation and performance exploration of the noble metal-non-noble metal bimetallic alloy catalytic material are subjects with important research significance. However, the above catalytic materials still have the problems of small specific surface area, non-uniform pore channels, difficult recovery, low catalytic activity, poor stability, etc.

The invention content is as follows:

the technical problem is as follows: the invention aims to provide a supported palladium-nickel bimetallic nano-alloy catalytic material and a preparation method thereof.

The technical scheme is as follows:

a supported palladium-nickel bimetallic nano-alloy catalytic material is characterized in that a carrier of the catalytic material is a yolk-eggshell type compound, wherein the inner core of the carrier is magnetic nano-iron particles, the shell of the carrier is a nitrogen-doped carbon polyhedron, and an active load is palladium-nickel bimetallic nano-alloy particles.

The nitrogen-doped carbon polyhedron is obtained by high-temperature carbonization of a covalent organic framework polymer formed by crosslinking 4, 4' -diaminobiphenyl and trihydroxy benzene. The size of the magnetic nano-iron particles is 10-50 nm, the thickness of the nitrogen-doped carbon polyhedron is 30-100 nm, and the size of the palladium-nickel bimetallic nano-alloy particles is 1-10 nm.

The specific preparation method of the catalytic material comprises the following steps:

a) preparing 0.2-0.8 wt% of ferric chloride aqueous solution at room temperature, adding 0.002-0.01 wt% of potassium dihydrogen phosphate aqueous solution according to the mass ratio of 0.005: 1-0.05: 1 of potassium dihydrogen phosphate to ferric chloride, stirring for reaction for 30-60 min, transferring to a reaction kettle, reacting for 36-72 h at 80-120 ℃, centrifugally separating, washing precipitate with 100-500 times of deionized water based on the mass of ferric chloride, and vacuum drying for 8-12 h at 70-100 ℃ to obtain Fe₂O₃A nanoparticle;

b) preparing a hydrochloric acid solution with the mass fraction of 0.1-0.4 wt% at room temperature, adding 4, 4 '-diaminobiphenyl according to the mass ratio of 0.001: 1-0.004: 1 of the 4, 4' -diaminobiphenyl to the hydrochloric acid solution, adding a sodium nitrite solution with the mass fraction of 0.5-1.0 wt% according to the mass ratio of 0.2: 1-0.4: 1 of the sodium nitrite solution to the hydrochloric acid solution, uniformly mixing and stirring at 0-4 ℃, and adjusting the pH of the mixed solution to 6-8 by using an inorganic alkaline water solution with the mass fraction of 10-50 wt% to obtain an aminobiphenyl mixed solution;

c) preparing 0.5-5 wt% of sodium carbonate aqueous solution at room temperature according to Fe₂O₃Adding the Fe prepared in the step a) into the nano particles and sodium carbonate at a mass ratio of 0.2: 1-1: 1₂O₃Nanoparticles of trihydroxybenzene and Fe₂O₃Adding trihydroxy benzene into the nano particles according to the mass ratio of 0.2: 1-1: 1, mixing and stirring for 30-60 min at 0-4 ℃ to obtain trihydroxy benzene mixed solution, adding the aminobiphenyl mixed solution prepared in the step b) into the trihydroxy benzene mixed solution according to the mass ratio of 1: 1-5: 1 of aminobiphenyl mixed solution and trihydroxy benzene mixed solution, stirring and reacting for 10-15 h at 0-4 ℃, performing centrifugal separation, and sequentially using 100-500 times of Fe₂O₃Washing and precipitating with deionized water and ethanol with the mass of nano particles, and drying in vacuum at 60-80 ℃ for 10-12 h to obtain Fe₂O₃-a covalent organic framework polymer core-shell complex;

d) according to Fe₂O₃The mass ratio of the covalent organic framework polymer core-shell compound to the deionized water is 0.01: 1-0.1: 1, and the Fe prepared in the step c) is added₂O₃-covalent organic framework polymer core-shell complexes dispersed in deionized water as palladium source with Fe₂O₃Adding a palladium source into the covalent organic framework polymer core-shell composite according to the mass ratio of 0.01: 1-0.1: 1, adding a nickel source into the covalent organic framework polymer core-shell composite according to the mass ratio of 0.2: 1-2: 1 of the nickel source and the palladium source, ultrasonically dispersing for 30-60 min, adjusting the pH of the solution to 10-14 by using a sodium hydroxide aqueous solution with the mass fraction of 0.1-1 wt%, stirring and reacting for 2-8 h, centrifugally separating, precipitating and using 50-500 times of Fe₂O₃-covalent organic frameworksWashing the polymer core-shell composite with deionized water, and vacuum drying at 60-80 ℃ for 8-12 h to obtain Fe₂O₃-a covalent organic framework polymer/Pd-Ni alloy composite;

e) subjecting the Fe obtained in step d)₂O₃Placing the covalent organic framework polymer/Pd-Ni alloy composite material in a tubular furnace, introducing reducing gas, adjusting the gas flow to 0.2-3 m L/min, reducing for 2-6 h at 600-800 ℃, and cooling to room temperature to obtain the supported palladium-nickel bimetallic nano alloy catalytic material.

The preparation method of the supported palladium-nickel bimetallic nano-alloy catalytic material is characterized in that the inorganic base in the step b) is one of sodium hydroxide, sodium carbonate and sodium bicarbonate. The palladium source in the step d) is one of palladium chloride and palladium acetate, and the nickel source is one of nickel nitrate, nickel acetate and nickel chloride. The reducing gas in the step e) is a hydrogen-helium mixed gas with the volume ratio of 1: 5-1: 10. The invention has the characteristics that:

(1) the catalytic material carrier is a yolk-eggshell type compound, and the nitrogen-doped carbon polyhedron of the shell of the carrier has a higher specific surface area, so that the adsorption effect of the catalyst on a reaction medium can be promoted; the magnetic iron particles in the carrier core have stronger magnetic response characteristics, and can be convenient for the recovery of the catalyst in liquid phase reaction.

(2) The active load of the catalytic material is palladium-nickel bimetallic nano-alloy particles, and the introduction of nickel can improve the chemical environment of the palladium particles, improve the catalytic activity of the catalyst and reduce the cost of the catalyst.

(3) Covalent organic framework polymer formed by crosslinking 4, 4' -diaminobiphenyl and trihydroxybenzene is used as a sacrificial template, and palladium-nickel alloy nanoparticles can be directionally anchored, so that the dispersibility of an active load on catalysis is improved.

The specific embodiment is as follows: