阅读说明：本技术 一种Z-Scheme AgBr/Ag8W4O16光催化剂的合成方法 (Z-Scheme AgBr/Ag8W4O16Method for synthesizing photocatalyst ) 是由 刘孝恒 殷鸿飞 于 2019-08-16 设计创作，主要内容包括：本发明公开了一步合成可见光响应的直接Z-Scheme AgBr/Ag_8W_4O_(16)光催化剂的方法。该光催化剂在微观上为纳米颗粒和微米棒构成的复合结构,在光催化降解罗丹明B方面表现出良好的催化活性。(The invention discloses a direct Z-Scheme AgBr/Ag for one-step synthesis of visible light response 8 W 4 O 16 a method of photocatalyst. The photocatalyst is a composite structure formed by nano particles and micron rods on the microcosmic aspect, and shows good catalytic activity in the aspect of photocatalytic degradation of rhodamine B.)

1.Z-Scheme AgBr/Ag₈W₄O₁₆The photocatalyst is characterized in that the AgBr/Ag₈W₄O₁₆The composite material is prepared from AgBr and Ag₈W₄O₁₆Prepared by a one-step method at room temperature according to the mass ratio of 5-30%.

2.Z-Scheme AgBr/Ag₈W₄O₁₆the method for synthesizing the photocatalyst is characterized by comprising the following steps of:

Firstly, adding cetyl trimethyl ammonium bromide into a sodium tungstate solution, and magnetically stirring for 2 hours to form a mixed solution in which tungstate ions and bromide ions coexist;

Secondly, dissolving silver nitrate in water with the same volume as the sodium tungstate solution in the first step;

Step three, dropwise adding the solution obtained in the step two into the solution obtained in the step one, and magnetically stirring for 6 hours at room temperature in a dark condition;

fourthly, centrifugally washing and drying the sample obtained in the third step to prepare AgBr/Ag₈W₄O₁₆a composite material.

3. The method of claim 2, wherein in the first step, the concentration of sodium tungstate is 10mM, and the concentration of cetyltrimethylammonium bromide is 15% to 54% of the concentration of sodium tungstate.

4. The method of claim 2, wherein in the second step, the concentration of the silver nitrate solution is 2 times the concentration of the sodium tungstate solution in the first step.

5. the method of claim 2, wherein in the fourth step, the rotation speed of the centrifuge is 9000r/min, the centrifugation time is 3min, and the oven temperature is 60 ℃.

Technical Field

the invention relates to Z-Scheme AgBr/Ag₈W₄O₁₆A synthesis method of a photocatalyst belongs to the field of nano material preparation.

Background

Environmental pollution and energy shortage are two major focus problems in the world at present, the photocatalysis technology is an ideal technology for solving the energy shortage and the environmental problem, solar energy is converted into chemical energy by utilizing a semiconductor photocatalysis material, beneficial products including hydrogen, hydrocarbon and the like are obtained, pollutants, bacteria and the like are removed, and the semiconductor photocatalysis technology is widely concerned. Silver tungstate (Ag)₂WO₄) Due to the fact that the forbidden band width of the ultraviolet light-emitting diode is large, the ultraviolet light-emitting diode has strong response to ultraviolet light and weak response to visible light, and the ultraviolet light only accounts for a very low proportion (-5%) in the solar spectrum, and the utilization of the ultraviolet light-emitting diode to the solar spectrum is greatly limited. To raise Ag₂WO₄The photocatalytic performance of (A) Ag/AgBr/Ag was prepared by ion exchange method using KBr as Br source by Shijie Li et al₂WO₄The photocatalyst is used for degrading RhB and tetracycline hydrochloride and shows purer Ag than pure Ag₂WO₄High-efficiency photocatalytic performance [ Shijie Li, et al. (2018) ]construction of a novel tertiary Ag/AgBr/Ag₂WO₄composite for efficient photocatalytic removal of Rhodamine B dye and tetracyclinehydrochloride antibiotic”Materials Letters 224:29-32.]. Jingking Li et al prepared Ag using NaCl, KBr, KI as halogen sources₂WO₄the/AgX (X ═ Cl, Br, I) photocatalyst is used for methyl orange degradation and shows a better than pure Ag₂WO₄High photocatalytic performance [ Jingjing Li, et al. (2015) ]simple formation of Ag₂WO₄/AgX(X＝Cl,Br,I)hybrid nanorods with enhanced visible-light-drivenphotoelectrochemical properties”Materials Research Bulletin 61:315-320]. As described above for Ag₂WO₄The photocatalytic performance is modified by a two-step ion exchange method, and the prepared Ag₂WO₄Are all alpha-Ag₂WO₄Therefore, there is a need to develop a method which is simple and can prepare a compound in comparison with alpha-Ag₂WO₄AgBr/Ag with higher performance₈W₄O₁₆The method of (1).

disclosure of Invention

The invention aims to provide Z-Scheme AgBr/Ag₈W₄O₁₆a method for synthesizing a photocatalyst.

the technical solution for realizing the purpose of the invention is as follows: AgBr and Ag₈W₄O₁₆Constructing direct Z-Scheme AgBr/Ag according to the mass ratio of 5-30%₈W₄O₁₆The system photocatalyst realizes the space separation of photoproduction electrons and cavities, thereby improving the photocatalytic performance.

The Z-Scheme AgBr/Ag₈W₄O₁₆The synthesis method of the photocatalyst comprises the following steps:

firstly, adding cetyl trimethyl ammonium bromide into a sodium tungstate solution, and magnetically stirring for 2 hours to form a mixed solution in which tungstate ions and bromide ions coexist;

Secondly, dissolving silver nitrate in water with the same volume as the sodium tungstate solution in the first step;

Third stepstep two, dropwise adding the solution obtained in the step two into the solution obtained in the step one, and magnetically stirring for 6 hours at room temperature in a dark place; fourthly, centrifugally washing and drying the sample obtained in the third step to prepare AgBr/Ag₈W₄O₁₆A composite material.

Further, in the first step, the concentration of sodium tungstate is 10mM, and the concentration of cetyl trimethyl ammonium bromide is 15% -54% of the concentration of sodium tungstate.

Further, in the second step, the concentration of the silver nitrate solution is 2 times of that of the sodium tungstate solution in the first step.

Furthermore, in the fourth step, the rotating speed of the centrifuge is 9000r/min, the centrifugation time is 3min, and the temperature of the oven is 60 ℃.

compared with the prior art, the invention has the advantages that: (1) adopting one-step method to prepare AgBr/Ag₈W₄O₁₆The composite material has mild reaction conditions and simple operation; (2) the material is used for photocatalytic degradation of rhodamine B, and shows excellent catalytic performance.

drawings

FIG. 1 is a synthetic scheme of the present invention.

FIG. 2 is an XRD diffraction pattern of the materials prepared in examples 1-4 and comparative examples 1 and 2 of the present invention.

FIG. 3(a) is comparative example 1 of the present invention, (b) is example 1, (c) is example 2, (d) is example 3, (e) and (f) are transmission electron microscopy (d-f) images of the material prepared in example 4.

FIG. 4 is a graph of the concentration of RhB for photocatalytic degradation over time for materials prepared in examples 1-4 of the present invention, and comparative examples 1, 2.

FIG. 5 is a graph showing the photocatalytic rate of the materials prepared in examples 1 to 4 of the present invention and comparative examples 1 and 2 for the photocatalytic degradation of RhB.

Detailed Description

FIG. 1 is a synthetic flow chart of the present invention, wherein cetyltrimethylammonium bromide is added to a sodium tungstate solution, and the mixture is magnetically stirred for 2 hours to form a mixed solution in which tungstate ions and bromide ions coexist; silver nitrate was dissolved in an equal volume of water as the sodium tungstate solution. Adding silver nitrate solution dropwise into solution containing sixteen ingredientsstirring in sodium tungstate solution of alkyl trimethyl ammonium bromide at room temperature in dark place for 6h, centrifuging, washing and drying to obtain AgBr/Ag₈W₄O₁₆A composite material.

AgBr/Ag prepared by the invention₈W₄O₁₆The composite material has excellent photocatalytic performance as a photocatalyst, which is mainly attributed to AgBr and Ag₈W₄O₁₆The Z-scheme heterojunction is formed between the two layers, so that space separation of photon-generated electrons and holes is realized, and the carrier recombination efficiency is reduced, thereby greatly improving the photocatalytic performance.

AgBr/Ag of the invention₈W₄O₁₆The composite photocatalyst is prepared by the following steps:

Firstly, adding cetyl trimethyl ammonium bromide into a sodium tungstate solution, and magnetically stirring for 2 hours to form a mixed solution in which tungstate ions and bromide ions coexist;

Secondly, dissolving silver nitrate in water with the same volume as the sodium tungstate solution in the first step;

step three, dropwise adding the solution obtained in the step two into the solution obtained in the step one, and stirring for 6 hours at room temperature in a dark place;

Step four, centrifugally washing the sample obtained in the step three, and drying in a drying oven to obtain AgBr/Ag₈W₄O₁₆A composite material.