阅读说明：本技术 锌镉硫-铋掺杂埃洛石复合光催化剂及其制备方法 (Zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst and preparation method thereof ) 是由 刘孝恒 张敏 于 2019-08-16 设计创作，主要内容包括：本发明公开了一种锌镉硫-铋掺杂埃洛石复合光催化剂及其制备方法。所述的锌镉硫-铋掺杂埃洛石复合光催化剂中,埃洛石为纳米管结构,锌镉硫分散的生长在铋掺杂埃洛石表面。本发明采用一步溶剂热法制得改性铋掺杂埃洛石,与锌镉硫超声复合形成复合光催化剂。本发明的锌镉硫-铋掺杂埃洛石复合光催化剂分散性好且活性位点多,用于光催化降解10mg/L罗丹明B,表现出优异的催化性能,在60min内降解率达到85％以上。(The invention discloses a zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst and a preparation method thereof. In the zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst, the halloysite is in a nanotube structure, and zinc-cadmium-sulfur is dispersedly grown on the surface of the bismuth doped halloysite. The invention adopts a one-step solvothermal method to prepare modified bismuth-doped halloysite, and the modified bismuth-doped halloysite and zinc-cadmium-sulfur are ultrasonically compounded to form the composite photocatalyst. The zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst has good dispersibility and multiple active sites, is used for photocatalytic degradation of 10mg/L rhodamine B, shows excellent catalytic performance, and has a degradation rate of over 85 percent within 60 min.)

1. the preparation method of the zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst is characterized by comprising the following steps of:

Step 1, uniformly dispersing halloysite in a saturated aluminum trichloride solution, adding an ethylene glycol solution of bismuth nitrate pentahydrate, stirring and mixing uniformly, carrying out solvothermal reaction at 160-180 ℃, naturally cooling after the reaction is finished, centrifuging, washing, and drying to obtain bismuth-doped halloysite;

And 2, ultrasonically dispersing bismuth-doped halloysite in water, adding cadmium acetate dihydrate and zinc acetate dihydrate, ultrasonically stirring, adding thioacetamide, ultrasonically stirring for reaction, centrifuging, washing and drying to obtain the zinc-cadmium-sulfur-bismuth-doped halloysite composite photocatalyst.

2. the method according to claim 1, wherein in step 1, the molar ratio of bismuth nitrate pentahydrate to halloysite is 1: 5.

3. The method according to claim 1, wherein in step 1, the halloysite is ultrasonically dispersed in a saturated aluminum trichloride solution and then stirred until the mixture is uniformly mixed.

4. the process according to claim 1, wherein in the step 1, the stirring and mixing time is 0.5 hours or more, and the solvothermal reaction time is 24 hours or more.

5. The preparation method according to claim 1, wherein in the step 1, the centrifugation rate is 9000r/min, and the drying temperature is 60-80 ℃.

6. The method according to claim 1, wherein in step 2, the molar ratio of the cadmium acetate dihydrate, the zinc acetate dihydrate and the thioacetamide is 1:4: 5.

7. the method of claim 1, wherein in step 2, the ratio of bismuth-doped halloysite to thioacetamide is 100mg:1 mmol.

8. the preparation method according to claim 1, wherein in the step 2, the ultrasonic stirring reaction time is more than 2h, the centrifugal rate is 9000r/min, and the drying temperature is 60-80 ℃.

9. The zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst in photocatalytic degradation of organic dyes according to claim 9.

Technical Field

The invention relates to a zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst and a preparation method thereof, belonging to the technical field of nano material preparation.

Background

the photocatalysis technology utilizes the unique light and electricity conversion characteristics of the material to convert solar energy into chemical energy, obtains energy substances including hydrogen, hydrocarbon and the like, and removes pollutants, bacteria and the like. However, the application of the existing photocatalyst is limited by the factors of low light utilization rate, high recombination rate of photo-generated electrons, few surface active sites and the like. The photocatalytic performance of the photocatalyst can be improved by modifying the photocatalyst, and the modification method comprises noble metal doping, semiconductor compounding, defect or heteroatom introduction, photosensitizer addition and the like.

halloysite is a natural clay silicate mineral and has the advantages of large specific surface area, abundant reserves, good thermal stability, uniform structure and the like. The halloysite has a chemical composition similar to that of kaolin and has a chemical formula of Al₂Si₂O₅(OH)₄·nH₂O (n ═ 0, 2), a tubular structure formed by the spatial misfit dislocations between aluminum oxy octahedra and silicon oxy tetrahedra. The inner surface of the halloysite micron tube is Al-OH and presents electronegativity, and the outer surface is O-Si-O groups and presents electropositivity. Thus, halloysite enables the vast majority of metal particles or ions (Pt, Fe)³⁺，Ag⁺etc.), metal compound (Fe)₃O₄CdS, CuO, etc.) and high molecular polymers (polyaniline, polythiophene, etc.) are uniformly loaded on the halloysite. Siva Kumar-Krishan et al functionalize the Surface of halloysite nanotubes for enzyme immobilization and biosensing by silver nanoparticle modification [ Siva Kumar-Krishan, et al (2016). ] A Surface functionalized halloysite nanoparticles isolated with silver nanoparticles for enzyme immobilization and biosensing.]. Xing, W.N. CdS-halloysite composites prepared by hydrothermal method are used for degrading tetracycline and have high-efficiency photocatalytic activity [ Xing, W.N., et al. (2012) ] "Preparation high photocatalytic activity of CdS/Halloyite Nanotubes (HNTs) with hydrothermal method" Applied Surface Science,259,698-704.]. The Halloysite @ Polyaniline (HNT @ PANI) core-shell nano composite nanotube prepared by in-situ polymerization of Zhou, T.Z. and the like has high-efficiency Cr (VI) Adsorption Reduction effect [ Zhou, T.Z., et al (2017) ] "Effective Adsorption/Reduction of Cr (VI) Oxyanison by Halloysite @ Polyaniline" ACS appl]. Yin, L.X. Zn prepared by hydrothermal method_0.2Cd_0.8The degradation rate of 10mg/L RhB of S microspheres in 60min is only 50% [ Yin, L.X., et al (2019). ] of' structural 3D structural Zn_0.2Cd_0.8Smicrospheres for the improved visible-light-drivenphotocatalytic performance."InternationalJournal of Hydrogen Energy,doi:10.1016]. The modification modes all use natural silicate as a carrier, and halloysite is not used as a photocatalystParticipate in the photocatalytic reaction, and simultaneously prepare single zinc-cadmium-sulfur nanocrystalline with agglomeration phenomenon.

Disclosure of Invention

The invention aims to provide a zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst with excellent catalytic performance and a preparation method thereof.

the technical scheme for realizing the purpose of the invention is as follows:

The preparation method of the zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst comprises the following steps:

Step 1, uniformly dispersing halloysite in a saturated aluminum trichloride solution, adding an ethylene glycol solution of bismuth nitrate pentahydrate, stirring and mixing uniformly, carrying out solvothermal reaction at 160-180 ℃, naturally cooling after the reaction is finished, centrifuging, washing, and drying to obtain bismuth-doped halloysite;

And 2, ultrasonically dispersing bismuth-doped halloysite in water, adding cadmium acetate dihydrate and zinc acetate dihydrate, ultrasonically stirring, adding thioacetamide, ultrasonically stirring for reaction, centrifuging, washing and drying to obtain the zinc-cadmium-sulfur-bismuth-doped halloysite composite photocatalyst.

Preferably, in step 1, the molar ratio of bismuth nitrate pentahydrate to halloysite is 1: 5.

Preferably, in step 1, the halloysite is ultrasonically dispersed in a saturated aluminum trichloride solution and then stirred until the mixture is uniformly mixed.

preferably, in step 1, the stirring and mixing time is 0.5h or more, and the solvothermal reaction is 24h or more.

Preferably, in the step 1, the centrifugation rate is 9000r/min, and the drying temperature is 60-80 ℃.

Preferably, in step 2, the molar ratio of the cadmium acetate dihydrate, the zinc acetate dihydrate and the thioacetamide is 1:4: 5.

Preferably, in step 2, the ratio of bismuth-doped halloysite to thioacetamide is 100mg:1 mmol.

Preferably, in the step 2, the ultrasonic stirring reaction time is more than 2 hours, the centrifugal rate is 9000r/min, and the drying temperature is 60-80 ℃.

The zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst prepared by the preparation method disclosed by the invention has a nanotube structure on the micro scale, and zinc-cadmium-sulfur is dispersedly grown on the surface of bismuth doped halloysite.

compared with the prior art, the invention has the following advantages:

(1) Preparing modified bismuth-doped halloysite by adopting a one-step solvothermal method, and ultrasonically compounding the modified bismuth-doped halloysite with zinc, cadmium and sulfur to form a composite photocatalyst; (2) the halloysite raw material is rich in resources, low in price and easy to obtain, and the pretreatment mode is simple; (3) the zinc-cadmium-sulfur-bismuth doped halloysite composite photocatalyst is used for photocatalytic degradation of 10mg/L rhodamine B, shows excellent catalytic performance, and has a degradation rate of over 85% within 60 min.

drawings

FIG. 1 is a scheme of the synthesis scheme of the preparation process of the present invention.

Fig. 2 is an optical image of unmodified halloysite nanotubes (a) and bismuth-doped halloysite (B) prepared in example 1.

Fig. 3 is a schematic representation of the doping atom pattern of the bismuth-doped halloysite prepared in example 1.

FIG. 4 is a high resolution transmission electron microscope image of undoped halloysite nanotubes (A), bismuth-doped halloysite nanotubes (B), zinc cadmium sulfur-halloysite nanocomposites (C), zinc cadmium sulfur-bismuth-doped halloysite nanocomposites (D and E), zinc cadmium sulfur nanoparticles (F).

FIG. 5 is a transmission electron microscope image of zinc cadmium sulfide-bismuth doped halloysite prepared in comparative example 1(A) and comparative example 2 (B).

figure 6 is an XRD diffractogram of the materials prepared in example 1, example 2 and comparative example 1.

Fig. 7 is a graph of the catalytic performance of the zinc cadmium sulfide-bismuth doped halloysite prepared in example 2 and comparative example 1.

Detailed Description

The present invention will be described in more detail with reference to the following examples and the accompanying drawings.

FIG. 1 is a diagram showing the synthetic mechanism of the preparation method of the present invention, in which halloysite is dispersed in a saturated aluminum chloride solution after pretreatment; bismuth nitrate pentahydrate is dispersed in ethylene glycol. And mixing the solutions, transferring the mixed solution into a polytetrafluoroethylene reaction kettle, taking out the solution after solvothermal reaction, and centrifugally washing and drying the solution to obtain the bismuth-doped halloysite material. And dispersing Bi-doped halloysite in deionized water, sequentially adding cadmium acetate dihydrate, zinc acetate dihydrate and thioacetamide, ultrasonically stirring, centrifuging, washing and drying to obtain the zinc-cadmium-sulfur-bismuth-doped halloysite composite material.