阅读说明：本技术 一种二维层状氯氧铋-Fe掺杂改性的光催化材料的制备方法与应用 (Preparation method and application of two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material ) 是由 陈小卫 奚新国 许琦 姜瑞雨 陈俊 徐风广 于 2020-06-23 设计创作，主要内容包括：本发明公开了一种二维层状氯氧铋-Fe掺杂改性的光催化材料的制备方法与应用。采用新颖的熔融盐(NaNO<Sub>3</Sub>和KNO<Sub>3</Sub>)法制备了纯BiOCl及Fe掺杂改性的BiOCl。首先称取一定质量比的NaNO<Sub>3</Sub>和KNO<Sub>3</Sub>混磨,然后向混合盐中加入Bi(NO<Sub>3</Sub>)<Sub>3</Sub>·5H<Sub>2</Sub>O、KCl和Fe(NO<Sub>3</Sub>)<Sub>3</Sub>·9(H<Sub>2</Sub>O),混磨均匀。再将混混磨粉末置于氧化铝坩埚中,进行热处理,最后得到Fe掺杂改性的BiOCl。本发明成本低、效率高、环境友好、安全便利,过程简单等优点,所得的Fe掺杂改性的BiOCl材料是典型层-层结构具有较多的表面活性区域,具有可见光响应,光催化性能稳定,因此在制备新型光催化剂上具有重大的潜在应用价值。(The invention discloses a preparation method and application of a two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material. Using novel molten salts (NaNO) 3 And KNO 3 ) The method prepares pure BiOCl and Fe-doped modified BiOCl. Firstly, weighing NaNO with a certain mass ratio 3 And KNO 3 Mixing and grinding, then adding Bi (NO) into the mixed salt 3 ) 3 •5H 2 O, KCl and Fe (NO) 3 ) 3 •9(H 2 O), and uniformly mixing and grinding. And then placing the mixed powder into an alumina crucible for heat treatment to obtain the Fe-doped modified BiOCl. The invention has the advantages of low cost, high efficiency, environmental protection, safety and convenience, and simple processThe obtained Fe-doped modified BiOCl material has the advantages of a typical layer-layer structure, more surface active areas, visible light response and stable photocatalytic performance, and therefore has great potential application value in preparation of novel photocatalysts.)

1. A preparation method of a two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material is characterized by comprising the following steps of:

step 1, mixing the raw materials in a mass ratio of 1:1 weighing raw material NaNO₃And KNO₃Mixing, placing in a mortar, and adding Bi (NO) into the mixed molten salt₃)₃•5H₂O, 1.0000g KCl and Fe (NO)₃)₃•9(H₂O), fully grinding for 3h to obtain mixed powder, wherein the Fe (NO) is₃)₃•9(H₂O) and Bi (NO)₃)₃•5H₂The molar ratio of O is a value x, wherein x is 0-0.20; the content of Fe doping is changed by changing Fe (NO)₃)₃•9(H₂O)/ Bi (NO₃)₃•5H₂The mol ratio of O realizes the doping of Fe in a BiOCl bulk phase, and the doping can be marked as xFe-BOC (x = 0-0.20);

step 2, placing the mixed powder into an alumina crucible, synthesizing for 3 hours in a muffle furnace at 400 ℃, and naturally cooling to ambient temperature to obtain a semi-finished product;

and 3, taking out the semi-finished product, repeatedly carrying out centrifugal washing, and then placing the washed sample powder in an oven for drying.

2. The preparation method of the two-dimensional layered bismuth oxychloride-Fe-doped modified photocatalytic material as claimed in claim 1, wherein the raw material NaNO used in step 1 is₃、KNO₃、Bi(NO₃)₃•5H₂O、KCl、Fe(NO₃)₃•9(H₂O) are all analytically pure, x is 0.05.

3. The preparation method of the two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material as claimed in claim 1, wherein the heating rate of the muffle furnace synthesis in step 2 is kept at 5-10 ℃/min.

4. The preparation method of the two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material as claimed in claim 1, wherein the centrifugation speed in step 3 is 4000 r/min.

5. The preparation method of the two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material as claimed in claim 1, wherein the specific steps of washing and drying in step 3 are as follows: and (3) washing the semi-finished product with an absolute ethyl alcohol water solution with the volume ratio of 1:1 for 5-10 times, and drying in an oven environment at 80 ℃.

6. The application of the two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material disclosed by claim 1 in degradation of RhB solution.

Technical Field

The invention relates to the technical field of photocatalysis, in particular to a preparation method and application of a two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material.

Background

With the continuous progress of industrialization and urbanization, the pollution problem caused by waste gas, organic matter, polymers, biomass, etc. becomes more severe. Among them, some of the artificially synthesized organic pollutants have high toxicity despite their low concentration in the environment, and thus it is necessary to convert the pollutants into non-toxic (or low-toxic) substances without generating secondary pollution through an efficient and "green" treatment technique. Currently, several physical and chemical methods have been used to solve this problem. The physical treatment technology mainly comprises adsorption, ultrafiltration, flocculation and the like, and the chemical treatment technology mainly comprises ozone oxidation, ultraviolet irradiation, hydrogen peroxide oxidation, semiconductor photocatalytic degradation, supercritical water oxidation, Fenton process, sound wave degradation, electrochemical treatment, electron beam treatment process, solvated electron reduction, iron permeation reaction wall, enzyme treatment process and the like. The semiconductor photocatalysis technology can completely eliminate organic pollutants, and has the advantages of high reaction speed, low process cost, mild operation conditions and environmental friendliness, so that the semiconductor photocatalysis technology becomes one of the most effective and green methods for removing organic pollutants.

At present, the photocatalytic material is limited in industrial production and practical application due to the complex synthesis process, low visible light utilization rate, low organic mineralization rate and poor catalyst stability.

In recent years, bismuth oxychloride (BiOCl) -based photocatalytic materials attract attention of many researchers due to the characteristics of rich sources, no toxicity, stability, unique optical and electrical properties and the like. BiOCl is a typical ternary semiconductor compound of main groups v-vi-viiIn which the halogen Cl ion forms [ Cl₂]^2-Layer, bismuth and oxygen form [ Bi₂O₂]²⁺And (3) a layer. [ Cl ]₂]^2-Layer and [ Bi ]₂O₂]²⁺The layers alternate to form a tetragonal crystal structure ([001 ] in the c-axis direction]). However, the BiOCl has a large band gap value and cannot be excited by visible light, so that the full utilization of solar energy is limited, and the practical application is hindered.

Many methods have been used to improve the visible light absorption and photocatalytic performance of BiOCl, such as morphology control, crystal plane modulation, complex heterojunctions, and element doping. Wherein the elemental doping strategy maintains a unique static internal electric field and high separation of photoionized charges. It is worth noting that the element doping can form band gap states near the conduction band edge and the valence band edge, so that absorption of visible light to sub-band energy is induced, and photon-generated carrier recombination is inhibited. Many elements are used to dope bioactive carbon, such as manganese, zinc, iron, cobalt, Ce, W, Sn, etc. Especially, Fe has attracted more and more attention as a promising method. Since the size of Fe ions is similar to that of bismuth ions, Bi ions are easily substituted in the crystal structure. In addition, oxygen vacancies generated by Fe doping can improve the conductivity, improve the separation and migration of electron-hole pairs, and further improve the photocatalytic performance.

The melting method is widely applied to synthesis of micro-materials due to the advantages of low cost, high efficiency, environmental friendliness, safety, convenience and the like. Particularly, the exposed ions can be directly transported and participate in the reaction process, so that the reaction caused by dehydration of the hydrated ions is limited, and the reaction speed in the molten salt is greatly accelerated. The mass transfer rate in molten salts is higher than in liquid phase processes. This facilitates homogeneous synthesis of the material. And simultaneously, impurity atoms can enter into a lattice structure.

In conclusion, the molten salt method not only provides a remarkable way for improving the photocatalytic performance, but also opens up a new technical route for designing a large amount of doped photocatalysts. No NaNO is adopted in the BiOCl preparation₃-KNO₃As a molten salt, material synthesis has been reported, and no studies have been made on material modification.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a preparation method and application of a two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material₃And KNO₃The prepared Fe-doped BOC modified material has stronger catalytic degradation activity of sunlight response, in addition, the preparation process is simple, the energy consumption is low, the prepared material has high catalytic efficiency, and the application of the prepared material in the field of photocatalysis is widened.

In order to solve the problems of the prior art, the invention adopts the technical scheme that:

a preparation method of a two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material comprises the following steps:

step 1, mixing the raw materials in a mass ratio of 1:1 weighing raw material NaNO₃And KNO₃Mixing, placing in a mortar, and adding Bi (NO) into the mixed molten salt₃)₃•5H₂O, 1.0000g KCl and a mass Fe (NO) satisfying the molar ratio Bi/Fe =1/x₃)₃•9(H₂O), fully grinding for 3h to obtain mixed powder, wherein the Fe (NO) is₃)₃•9(H₂O) and Bi (NO)₃)₃•5H₂The molar ratio of O is a value x, wherein x is 0-0.20; the content of Fe doping is changed by changing Fe (NO)₃)₃•9(H₂O)/Bi(NO₃)₃•5H₂The mol ratio of O realizes the doping of Fe in a BiOCl bulk phase, and the doping can be marked as xFe-BOC (x = 0-0.20);

step 2, placing the mixed powder into an alumina crucible, synthesizing for 3 hours in a muffle furnace at 400 ℃, and naturally cooling to ambient temperature to obtain a semi-finished product;

and 3, taking out the semi-finished product, repeatedly centrifuging and washing, and drying in an oven to obtain a finished product.

As a modification, the source used in step 1NaNO material₃、KNO₃、Bi(NO₃)₃•5H₂O、KCl、Fe(NO₃)₃•9(H₂O) are all analytically pure, x is 0.05.

The improvement is that the temperature rise speed of the muffle furnace synthesis in the step 2 is kept at 5-10 ℃/min.

As a modification, the rate of centrifugation in step 3 was 4000 r/min.

As an improvement, the specific steps of washing and drying in the step 3 are as follows: and (3) washing the semi-finished product with an absolute ethyl alcohol water solution with the volume ratio of 1:1 for 5-10 times, and drying in an oven environment at 80 ℃.

The two-dimensional layered bismuth oxychloride-Fe doped modified photocatalytic material is applied to degradation of RhB solution.

The working principle is as follows: on one hand, the BiOCl nanosheet has a special energy band structure and certain visible light response capability; on the other hand, oxygen defect vacancies formed after metal Fe doping modification can facilitate the rapid separation of photo-generated electron-hole pairs, thereby improving the quantum yield, and further improving the photocatalytic degradation performance in the visible light response range.

Has the advantages that:

compared with the prior art, the preparation method of the two-dimensional layered bismuth oxychloride-Fe doped and modified photocatalytic material adopts novel molten salt (NaNO)₃And KNO₃) Pure BiOCl and metal (taking iron as an example) doping modified BiOCl thereof are prepared by the method. Firstly, weighing NaNO with a certain mass ratio₃And KNO₃Mixing and grinding, then adding Bi (NO) into the mixed salt₃)₃•5H₂O, KCl and a weight of Fe (NO)₃)₃•9(H₂O), and uniformly mixing and grinding. And then placing the mixed powder into an alumina crucible for heat treatment to obtain pure BiOCl-Fe doped and modified BiOCl.

The concrete advantages are as follows: the preparation method has the advantages of low cost, high efficiency, environmental friendliness, safety, convenience, simple process and the like, and the obtained Fe-doped modified BiOCl material has a typical layer-layer structure, more surface active regions, visible light response, stable photocatalytic performance and excellent degradation effect on RhB.

Drawings

FIG. 1 is an XRF pattern for a product of various embodiments of the present invention wherein (a) is BOC, xFe-BOC and (b) is BOC and 0.05 Fe-BOC;

FIG. 2 is an XPS spectrum of 0.05Fe-BOC of a sample obtained in example 3 of the present invention: (a) is a total map, (b) is a Bi 4f map, (c) is a Cl 2p map, (d) is a Fe2p map, and (e) is an O1 s map;

FIG. 3 is a SEM photograph and an EDS spectrum of example 3 of the present invention, wherein (a) is a SEM photograph of a sample BOC, (b) is a SEM photograph of 0.05Fe-BOC, (c) is an EDS spectrum of 0.05Fe-BOC, (d) is an EDS spectrum of Cl, (e) is an EDS spectrum of Bi, (f) is an EDS spectrum of O, and (g) is an EDS spectrum of Fe;

FIG. 4 is a UV-VIS absorption spectrum of BOC and Fe-BOC in example 3 of the present invention, wherein (a) is the UV-VIS absorption spectrum of BOC and Fe-BOC, and (b) is the converted UV-VIS bandgap spectrum;

FIG. 5 is a graph showing the effect of different proportions of Fe-BOC and BOC photocatalytic materials on simulated photocatalytic degradation of RhB solution in sunlight, wherein (a) is a concentration variation curve of Fe-BOC and BOC photocatalytic RhB dyes in different proportions under illumination, and (b) is a curve fitted according to kinetics of photocatalytic degradation of RhB;

FIG. 6 is a graph showing the effect of sunlight simulated photocatalytic degradation of RhB solution when the prepared 0.05Fe-BOC material is circulated for 5 times and the times are different;

FIG. 7 is a schematic view of the condensing apparatus of the present invention.

Detailed description of the preferred embodiment

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

(1) Preparing Fe body by molten salt methodAdding BiOCl, weighing 25g NaNO with the mass ratio of 1:1₃And KNO₃Mixed and milled, then 1.9403 g Bi (NO) is added to the mixed salt₃)₃•5H₂O, 1.0000g KCl and 0.0170 g Fe (NO)₃)₃•9(H₂O), mixing and grinding for 3 hours to obtain mixed powder;

(2) then putting the mixed and ground powder into an alumina crucible, annealing for 3h at 400 ℃, and naturally cooling to ambient temperature to obtain a semi-finished product;

(3) taking out the semi-finished product, repeatedly washing the semi-finished product by using a mixed solution of deionized water and absolute ethyl alcohol, and then putting the washed semi-finished product powder into an oven at 80 ℃ for drying overnight, (abbreviated as 0.01 Fe-BOC).