Method for preparing novel carbon-nitrogen nonmetal photocatalyst by utilizing p/n junction principle
阅读说明：本技术 一种利用p/n结原理制备新型碳氮非金属光催化剂的方法 (Method for preparing novel carbon-nitrogen nonmetal photocatalyst by utilizing p/n junction principle ) 是由 赵刚 徐锡金 邢钰鹏 马文萱 王小珂 郝树华 程艳玲 于 2019-08-16 设计创作，主要内容包括：本发明属于纳米能源材料技术领域,具体涉及一种利用p/n结原理制备新型碳氮非金属光催化剂的方法。本发明包括以下步骤：(1)将胺类原料和溶剂加热,得到第一产物；(2)将第一产物在惰性气体保护下,升温,加热,得到p型CN光催化剂；(3)将胺类原料混合卤素铵盐与溶剂加热,得到第二产物；(4)将第二产物在惰性气体保护氛围,升温,加热,得到n型CN光催化剂；(5)将p型CN光催化剂和研磨混合,再置于瓷舟内放入管式炉中,惰性气体保护氛围,升温,淬火,得到本发明的光催化剂。本发明利用p/n结原理制备新型碳氮非金属光催化剂,原材料环保,具有对环境无毒、所需条件低、产量高的特点,不需要昂贵的仪器设备。(The invention belongs to the technical field of nano energy materials, and particularly relates to a method for preparing a novel carbon-nitrogen nonmetal photocatalyst by utilizing a p/n junction principle. The invention comprises the following steps: (1) heating an amine raw material and a solvent to obtain a first product; (2) heating and heating the first product under the protection of inert gas to obtain a p-type CN photocatalyst; (3) mixing an amine raw material with halogen ammonium salt and a solvent, and heating to obtain a second product; (4) heating and heating the second product in an inert gas protective atmosphere to obtain an n-type CN photocatalyst; (5) and grinding and mixing the p-type CN photocatalyst, placing the mixture into a porcelain boat, placing the porcelain boat into a tube furnace, and heating and quenching the porcelain boat under the protection of inert gas to obtain the photocatalyst. The invention utilizes the p/n junction principle to prepare the novel carbon-nitrogen non-metal photocatalyst, has the characteristics of environment-friendly raw materials, no toxicity to the environment, low required conditions and high yield, and does not need expensive instruments and equipment.)
1. A method for preparing a novel carbon-nitrogen nonmetal photocatalyst by utilizing a p/n junction principle comprises the following steps:
(1) putting an amine raw material and a solvent into a container, and heating to obtain a first product;
(2) placing the first product in a porcelain boat and then in a tube furnace, heating the porcelain boat under the protection of inert gas to obtain a p-type CN photocatalyst;
(3) putting the amine raw material mixed with halogen ammonium salt and a solvent into a container, and heating to obtain a second product;
(4) placing the second product in a porcelain boat and then in a tube furnace, and heating the porcelain boat under the protection of inert gas to obtain an n-type CN photocatalyst;
(5) and grinding and mixing the p-type CN photocatalyst, placing the mixture into a porcelain boat, placing the porcelain boat into a tube furnace, protecting the atmosphere by inert gas, heating and quenching to obtain the non-metal p-CN/n-CN photocatalyst with the pn junction.
2. The method for preparing the novel carbon nitrogen non-metal photocatalyst by using the p/n junction principle as claimed in claim 1, comprising the following steps:
(1) placing an amine raw material and a solvent in a container, and heating for 6-24 hours at 100-180 ℃ to obtain a first product; the weight volume ratio of the amine raw material to the solvent is (1-10) g: (15-25) ml;
(2) placing the first product obtained in the step (1) in a porcelain boat, then putting the porcelain boat into a tube furnace, heating the porcelain boat to 500-650 ℃ at a heating rate of 1-6 ℃/min under the protection of inert gas, and heating the porcelain boat for 1-4 hours to obtain a p-type CN photocatalyst;
(3) putting the amine raw material mixed with halogen ammonium salt and a solvent into a container, and heating for 1-6 h at 100-180 ℃ to obtain a second product;
the weight volume ratio of the amine raw material to the solvent is as follows: (1-10) g: (15-25) ml;
(1) in the step (3), the solvent is at least one of deionized water or an organic solvent;
(4) placing the second product in a porcelain boat and then in a tube furnace, heating to 500-650 ℃ at a heating rate of 1-6 ℃/min under the protection of inert gas, and heating for 1-4 h to obtain an n-type CN photocatalyst;
(5) grinding and mixing the p-type CN photocatalyst obtained in the step (2) and the n-type CN photocatalyst obtained in the step (4) according to the mass ratio of 1:1, placing the mixture into a porcelain boat, placing the porcelain boat into a tubular furnace, raising the temperature to 500-650 ℃ at the temperature rise rate of 1-6 ℃/min under the protection of inert gas, and quenching for 0.5-1 h to obtain the non-metal p-CN/n-CN photocatalyst with the pn junction.
3. The method for preparing a novel carbon-nitrogen non-metal photocatalyst by using the p/n junction principle as claimed in claim 1, wherein (1) and (3) said amine raw material is at least one of melamine, urea and polyethylene diamine.
4. The method for preparing a novel carbon-nitrogen non-metal photocatalyst by using the p/n junction principle as claimed in claim 1, wherein in (1) and (3), the solvent is at least one of deionized water, ethanol and tetrahydrofuran.
5. The method for preparing a novel carbon nitrogen non-metal photocatalyst by using the p/n junction principle as claimed in claim 1, wherein in (3), the halogen ammonium salt is at least one of ammonium fluoride, ammonium chloride and ammonium iodide.
6. The method for preparing the novel carbon nitrogen non-metal photocatalyst by using the p/n junction principle as claimed in claim 1, wherein the inert gas is at least one of argon and nitrogen.
7. The method for preparing a novel carbon-nitrogen non-metal photocatalyst by using the p/n junction principle as claimed in claim 1, wherein the obtained product is added into a photocatalytic performance tester to test the photocatalytic performance, and the performance is as follows: the yield of hydrogen production is 17028.82 mu molh-1g-1The total water splitting result was achieved without adding any sacrificial agent and noble metal in the water, and the average hydrogen production and average oxygen production were 270.9. mu. molh, respectively-1g-1And 115.21. mu. molh-1g-1。
Technical Field
The invention belongs to the technical field of preparation of nano energy materials, and particularly relates to a method for preparing a novel carbon-nitrogen nonmetal photocatalyst by utilizing a p/n junction principle.
Background
Two-dimensional (2D) graphene-based carbon-nitrogen photocatalysts (g to CxNy) have recently received extensive research attention due to their good visible light responsiveness, and have advantages of large specific surface area, no toxicity, low price, and the like. However, in the non-metal and fully hydrolyzed fields, the effect of the CN photocatalyst has hardly any major breakthrough in the past decades.
The present inventors searched a large number of patent documents and journal documents before studying the present invention. The search results indicated that all CN photocatalysts were n-type structures due to their different carbon to nitrogen ratios (d.j.martin, k.qiu, s.a.shevlin, a.d.handoko, x.chen, z.guoandj.tang, angelw.chem.int.ed.2014, 53,9240; b) x.h.li, j.s.zhang, x.f.chen, a.fischer, a.thomas, m.antonetti, and x.c.wang, chem.mater.2011,23,4344; c) liu, t.wang, h.b.zhang, x.g.meng, d.hao, k.chang, p.li, t.kakoandj.h.ye, angelw.chem.int.ed.2015, 54,13561.).
In general, most researchers use p-type metal-based materials and n-type CN to compound and obtain photocatalysts, and this idea comes from the pn junction principle of silicon-based solar cells. This structure can greatly improve the efficiency of the photocatalyst. For example, ZnO/g to C3N4Composite materials with pure g-C3N4In contrast, the photocatalyst has good photocatalytic activity (j.x.sun, y.p.yuan, l.g.qiu, x.jiang, a.j.xie, y.h.shen, j.f.zhu, dalton trans.2012,41,6756). However, the above-mentioned composite photocatalysts are not nonmetal photocatalysts, and many metal-based materials are expensive and toxic.
Therefore, aiming at the defects, a p-type nonmetal CN photocatalyst needs to be designed and then compounded with a common n-type nonmetal CN photocatalyst, so that a novel nonmetal p-CN/n-CN photocatalyst structure with a pn junction is invented.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for preparing a novel carbon-nitrogen nonmetal photocatalyst by utilizing a p/n junction principle, which has no toxicity to the environment, low required conditions, high yield and no need of expensive instruments and equipment;
the method for preparing the novel carbon-nitrogen non-metal photocatalyst by utilizing the p/n junction principle solves the technical problems by the following technical scheme:
a method for preparing a novel carbon-nitrogen nonmetal photocatalyst by utilizing a p/n junction principle comprises the following steps:
(1) putting an amine raw material and a solvent into a container, and heating to obtain a first product;
(2) placing the first product in a porcelain boat and then in a tube furnace, heating the porcelain boat under the protection of inert gas to obtain a p-type CN photocatalyst;
(3) putting the amine raw material mixed with halogen ammonium salt and a solvent into a container, and heating to obtain a second product;
(4) placing the second product in a porcelain boat and then in a tube furnace, and heating the porcelain boat under the protection of inert gas to obtain an n-type CN photocatalyst;
(5) and grinding and mixing the p-type CN photocatalyst, placing the mixture into a porcelain boat, placing the porcelain boat into a tube furnace, protecting the atmosphere by inert gas, heating and quenching to obtain the non-metal p-CN/n-CN photocatalyst with the pn junction.
Preferably, the method comprises:
(1) placing an amine raw material and a solvent in a container, and heating for 6-24 hours at 100-180 ℃ to obtain a first product; the weight volume ratio of the amine raw material to the solvent is (1-10) g: (15-25) ml;
(2) placing the first product obtained in the step (1) in a porcelain boat, then putting the porcelain boat into a tube furnace, heating the porcelain boat to 500-650 ℃ at a heating rate of 1-6 ℃/min under the protection of inert gas, and heating the porcelain boat for 1-4 hours to obtain a p-type CN photocatalyst;
(3) putting the amine raw material mixed with halogen ammonium salt and a solvent into a container, and heating for 1-6 h at 100-180 ℃ to obtain a second product;
the weight volume ratio of the amine raw material to the solvent is as follows: (1-10) g: (15-25) ml;
(1) in the step (3), the solvent is at least one of deionized water or an organic solvent;
(4) placing the second product in a porcelain boat and then in a tube furnace, heating to 500-650 ℃ at a heating rate of 1-6 ℃/min under the protection of inert gas, and heating for 1-4 h to obtain an n-type CN photocatalyst;
(5) grinding and mixing the p-type CN photocatalyst obtained in the step (2) and the n-type CN photocatalyst obtained in the step (4) according to the mass ratio of 1:1, placing the mixture into a porcelain boat, placing the porcelain boat into a tubular furnace, raising the temperature to 500-650 ℃ at the temperature rise rate of 1-6 ℃/min under the protection of inert gas, and quenching for 0.5-1 h to obtain the non-metal p-CN/n-CN photocatalyst with the pn junction.
(1) And (3) the amine raw material is at least one of melamine, urea and polyethylene diamine.
(1) And (3), the solvent is at least one of deionized water, ethanol and tetrahydrofuran.
(3) In the method, the halogen ammonium salt is at least one of ammonium fluoride, ammonium chloride and ammonium iodide as a solvent.
The inert gas is at least one of argon and nitrogen.
The product is added into a photocatalytic performance tester to test the photocatalytic performance, and the performance is as follows: the yield of hydrogen production is 17028.82 mu molh-1g-1The total water splitting result was achieved without adding any sacrificial agent and noble metal in the water, and the average hydrogen production and average oxygen production were 270.9. mu. molh, respectively-1g-1And 115.21. mu. molh-1g-1。
Compared with the prior proposal mentioned in the background technology, the experimental result in the invention shows that the nonmetal p-CN/n-CN photocatalyst of the novel nonmetal pn junction provided by the invention has good photocatalysis effect, and the novel nonmetal p-CN/n-CN photocatalyst has good photocatalysis effectThe yield of hydrogen production is 17028.82 mu molh-1g-1The catalytic performance of the photocatalyst is much better than that of other pure CN photocatalysts under the same experimental conditions. More importantly, the results of full water splitting were achieved without adding any sacrificial agent and noble metal to the water, with an average hydrogen production and an average oxygen production of 270.9. mu. molh, respectively-1g-1And 115.21. mu. molh-1g-1. Therefore, the novel CN photocatalyst with the p-n structure has wide application prospect.
The method has the advantages that the novel carbon-nitrogen nonmetal photocatalyst is prepared by utilizing the p/n junction principle, the equipment is simple, the raw materials are environment-friendly, the method has the characteristics of no toxicity to the environment, low required conditions and high yield, and expensive equipment is not needed.
Drawings
FIG. 1 is a scanning electron micrograph of a two-dimensional carbon nitrogen photocatalytic material prepared by the invention. Wherein a is a p-type semiconductor photocatalyst, b is an n-type, c is a p-n junction heterostructure CN photocatalyst, and d is a common carbon nitrogen photocatalyst;
FIG. 2 shows the photocatalytic performance of the two-dimensional carbon nitrogen photocatalytic material prepared by the present invention in water. Wherein a is the comparison of hydrogen production amount of CN photocatalysts with different structures, b is the comparison of hydrogen production efficiency of CN photocatalysts with different structures, c is the yield of hydrogen and oxygen prepared by hydrolyzing water by a p-n junction heterostructure CN photocatalyst under a 300w xenon lamp, and d is the efficiency of preparing hydrogen and oxygen by hydrolyzing water by a p-n junction heterostructure CN photocatalyst;
FIG. 3 is a diagram of the mechanism of hydrogen and oxygen generation for a p-n junction heterostructure CN photocatalyst prepared in accordance with the present invention;
FIG. 4 is a flow diagram of a process for preparing the catalyst of the present invention.
Detailed Description
The invention will be further described with reference to the accompanying drawings and specific embodiments so that those skilled in the art may better understand the invention, but the invention is not limited thereto.