阅读说明：本技术 一种导电凹凸棒石/氧化钛/氮化碳量子点复合材料及其制备方法和在光催化脱硫中的应用 (Conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material, preparation method thereof and application thereof in photocatalytic desulfurization ) 是由 姚超 吴红叶 左士祥 严向玉 李霞章 刘文杰 吴凤芹 王灿 于 2019-11-22 设计创作，主要内容包括：本发明属于纳米材料制备领域,一种导电凹凸棒石/氧化钛/氮化碳量子点复合材料及其制备方法和在光催化脱硫中的应用。本发明采用导电凹凸棒石,在导电凹凸棒石在水热生长氧化钛,形成毛刷状复合材料,然后在在毛刷状凹凸棒石/氧化钛上复合氮化碳量子点,氮化碳量子点与氧化钛形成异质结,可以加速电子与空穴的分离,提高材料对可见光的响应,提高可见光的利用率。将得到的复合材料用于光催化脱硫,能达到显著的脱硫效果。(The invention belongs to the field of nano material preparation, and relates to a conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material, a preparation method thereof and application thereof in photocatalytic desulfurization. According to the invention, the conductive attapulgite is adopted, titanium oxide is hydrothermally grown on the conductive attapulgite to form a hairbrush-shaped composite material, then carbon nitride quantum dots are compounded on the hairbrush-shaped attapulgite/titanium oxide, and the carbon nitride quantum dots and the titanium oxide form a heterojunction, so that the separation of electrons and holes can be accelerated, the response of the material to visible light is improved, and the utilization rate of visible light is improved. The obtained composite material is used for photocatalytic desulfurization, and can achieve remarkable desulfurization effect.)

1. A conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material is characterized in that: the composite material is composed of conductive attapulgite, titanium oxide and carbon nitride quantum dots.

2. The conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material of claim 1, wherein: the conductive attapulgite refers to the attapulgite with antimony-doped tin oxide coated on the surface.

3. The preparation method of the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material according to claim 2, wherein the preparation steps of the composite material are as follows:

(1) preparing a stable colloidal solution of the carbon nitride quantum dots, and marking the solution as CN-QD;

(2) adding conductive attapulgite into a mixed solution of titanium salt and hydrochloric acid, ultrasonically mixing, transferring into a reaction kettle, carrying out hydrothermal reaction, cooling to room temperature, carrying out suction filtration, washing and drying to obtain brush-shaped conductive attapulgite/titanium oxide;

(3) dispersing the conductive attapulgite/titanium oxide and the colloidal solution of the carbon nitride quantum dots in the step (1) into deionized water, ultrasonically mixing, transferring to a reaction kettle, carrying out hydrothermal reaction, cooling to room temperature, carrying out suction filtration, washing and drying to obtain the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material.

4. The preparation method of the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material according to claim 3, wherein the preparation method comprises the following steps: the hydrothermal reaction condition of the step (2) is hydrothermal for 4-12h at 60-100 ℃.

5. The preparation method of the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material according to claim 3, wherein the preparation method comprises the following steps: the concentration of the hydrochloric acid in the step (2) is 2mol/L, and the titanium salt solution is a titanium tetrachloride solution with the concentration of 3-5 mol/L; the mass ratio of the conductive attapulgite to the titanium salt solution is 2-0.5: 1; the volume ratio of the titanium salt solution to the hydrochloric acid solution is 1: 30.

6. The preparation method of the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material according to claim 3, wherein the preparation method comprises the following steps: the hydrothermal reaction condition of the step (3) is that the hydrothermal reaction is carried out for 2-6h at the temperature of 60-80 ℃.

7. The preparation method of the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material according to claim 3, wherein the preparation method comprises the following steps: the preparation method of the colloidal solution of the carbon nitride quantum dots comprises the following steps:

(1) mixing and grinding a nitrogen precursor, sodium chloride and potassium chloride, and calcining for 3-5h at the temperature of 650-700 ℃ in a muffle furnace after grinding to obtain a carbon nitride intermediate;

(2) grinding the carbon nitride intermediate into powder, washing the carbon nitride intermediate by using dilute hydrochloric acid, and centrifugally collecting a solid, wherein the solid is marked as a solid I; and then dispersing the solid I into deionized water, and centrifuging at 6000-10000rpm to remove large carbon nitride particles, thereby finally obtaining the stable colloidal solution of the carbon nitride quantum dots.

8. The preparation method of the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material according to claim 3, wherein the preparation method comprises the following steps: the mass ratio of the CN-QD sol to the attapulgite/titanium oxide composite material is 1-3: 10.

9. The use of the electrically conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material according to any one of claims 1-8 as a catalyst in photocatalytic desulphurization.

Technical Field

The invention belongs to the field of nano material preparation, and relates to a hydrothermal method for preparing a conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material with conductive attapulgite as a carrier and application of the composite material in photocatalytic desulfurization.

Background

Sulfur oxides (SOx) discharged from fuel combustion easily cause acid rain and haze, which become serious environmental pollution problems, and thus removal of sulfur-containing organic compounds in oil products is urgently needed. The traditional hydrodesulfurization process has harsh technological conditions, needs high temperature and high pressure and consumes a large amount of hydrogen, and oxidative desulfurization becomes a research hotspot due to the advantages of mild reaction conditions, no consumption of a large amount of hydrogen, low investment and the like. The photocatalytic desulfurization is a novel desulfurization technology for catalytic oxidation desulfurization by adopting a semiconductor catalyst with optical activity, has the advantages of mild reaction conditions, low energy consumption, environmental friendliness and the like, and is concerned. The principle is as follows: the semiconductor catalyst can generate electrons and holes under the excitation of light, and then reacts with an oxidant to generate superoxide anions and hydroxyl free radicals with strong oxidizing property, so that thiophene sulfides are oxidized into corresponding sulfone or sulfoxide polar sulfur-containing substances, and finally the sulfur-containing substances are removed through extraction.

Titanium oxide (TiO)₂) It is attracting attention as an environmentally friendly semiconductor which is nontoxic and harmless, has high stability and excellent photosensitivity. But TiO 2₂Has a wide band gap of 3.0eV, and absorbs only ultraviolet rays constituting a small part of sunlight, and TiO₂The photo-generated charge carriers in (1) are easily recombined, which is to TiO₂Adversely affects the photoelectrochemical properties of the film. It is therefore necessary to modify it to increase its photoresponsive rangeAnd electron separation efficiency.

Therefore, how to further improve the photoresponse range and the electron separation efficiency of the titanium oxide is a problem which is urgently needed to be solved at present.

Disclosure of Invention

The invention provides a composite material for photo-generated cathode protection, namely a conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material.

The invention also provides a preparation method of the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material, which comprises the following steps:

firstly, synthesizing a brush-shaped conductive attapulgite/titanium oxide binary material by using a hydrothermal method by using conductive attapulgite as a carrier; and then loading the carbon nitride quantum dots on the one-dimensional titanium oxide rod to obtain the conductive electric attapulgite/titanium oxide/carbon nitride quantum dot composite material.

The method comprises the following specific steps:

1. weighing the nitrogen-rich precursor, sodium chloride and potassium chloride, mixing and grinding, then calcining for 3-5h in a muffle furnace at 650-700 ℃, and grinding the obtained carbon nitride intermediate into powder. Then washing the carbon nitride intermediate by using dilute hydrochloric acid, and centrifugally collecting a solid, wherein the solid is marked as a solid I; and then dispersing the solid I into deionized water, centrifuging at 6000-10000rpm to remove large carbon nitride particles, and finally obtaining a stable colloidal solution of the carbon nitride quantum dots, which is marked as CN-QD.

Wherein the nitrogen-rich precursor is one of melamine, dicyandiamide and urea, the molar ratio of sodium chloride to potassium chloride is 1:1, the molar ratio of the nitrogen-rich precursor to sodium chloride is 0.75:1, and the mass ratio of dilute hydrochloric acid to the carbon nitride intermediate is 10: 1, the mass ratio of deionized water to the solid I is 20:1, and the concentration of dilute hydrochloric acid is 1-2M.

2. Adding conductive attapulgite into a mixed solution of titanium salt and hydrochloric acid, performing ultrasonic treatment for 20-40min, transferring to a Teflon lining, performing hydrothermal treatment at 60-100 deg.C for 4-12h, cooling to room temperature, performing suction filtration, washing, and drying at 60-80 deg.C to obtain brush-shaped conductive attapulgite/titanium oxide.

Wherein the concentration of the hydrochloric acid is 2mol/L, the titanium salt solution is a titanium tetrachloride solution, the concentration is 3-5mol/L, and the mass ratio of the conductive attapulgite to the titanium salt solution is 2-0.5: 1, the volume ratio of the titanium salt solution to the hydrochloric acid solution is 1: 30.

The conductive attapulgite is prepared by coating Sb-doped tin oxide on the surface of attapulgite and has the function of guiding the generation of rod-shaped titanium oxide.

When the conventional attapulgite is used for loading titanium oxide, the titanium oxide can be loaded on the attapulgite only in the form of nano particles, and a plurality of free particles can form a heterojunction with subsequent carbon nitride quantum dots, so that the problems of low light utilization rate and high electron and hole recombination rate of the composite material can not be effectively solved.

3. Dispersing the colloidal solution of the conductive attapulgite/titanium oxide and the carbon nitride quantum dots into deionized water, carrying out ultrasonic treatment for 20-30 minutes, transferring the mixture to a Teflon lining, carrying out hydrothermal treatment for 2-6 hours at the temperature of 60-80 ℃, cooling to room temperature, carrying out suction filtration washing, and drying at the temperature of 60-80 ℃ to obtain the conductive attapulgite/titanium oxide/carbon nitride quantum dot composite material.

Wherein the mass ratio of the attapulgite/titanium oxide composite material to the deionized water is 1:20, and the mass ratio of the CN-QD sol to the attapulgite/titanium oxide composite material is 1-3: 10.

The invention has the beneficial effects that:

1. the conductive attapulgite is used as a carrier, the short rod-shaped titanium oxide is grown hydrothermally to form brush-shaped conductive attapulgite/titanium oxide, and the one-dimensional rod-shaped titanium oxide has larger specific surface area and excellent electron transport performance compared with titanium oxide particles, so that the photoelectrochemical performance can be greatly improved.

2. According to the invention, the carbon nitride quantum dots are compounded on the brush-shaped attapulgite/titanium oxide, and the one-dimensional rod-shaped titanium oxide has a larger specific surface area, so that a heterojunction can be formed with the carbon nitride quantum dots, the separation of electrons and holes can be accelerated, the response of the material to visible light is improved, and the utilization rate of the visible light is improved.

Drawings

FIG. 1 is a transmission electron micrograph of the material prepared in example 1;

FIG. 2 is a transmission electron micrograph of the material prepared in comparative example 4;

FIG. 3 is a graph showing the change of desulfurization degree with time in the use of the materials prepared in example 1 and comparative example 1, comparative example 2, comparative example 3, and comparative example 4;

FIG. 4 is a Uv-vis diagram for example 1 and comparative examples 1 and 2.

Detailed Description

The invention is further described below with reference to examples and comparative examples, but the scope of protection of the invention is not limited to the ranges referred to in the examples: