阅读说明：本技术 一种卵状碳包裹单晶二氧化钛微球的制备方法及其应用 (Preparation method and application of ovoid carbon-coated single-crystal titanium dioxide microspheres ) 是由 杨化桂 宋宁宁 杨晓华 刘鹏飞 侯宇 袁海洋 于 2019-11-29 设计创作，主要内容包括：本发明公开了一种卵状碳包裹单晶二氧化钛微球的制备方法及其应用。本发明采用一步水热法合成无定型碳包裹二氧化钛单晶微球。微球尺寸为1～1.5微米,其中外壳碳层为无定型结构、内核二氧化钛为锐钛矿单晶结构。该方法操作简便,工艺设备简单,原料易得,制备成本较低,反应周期短,可重复性高。这种材料应用在光催化降解有机污染物方面有着突出的性能。这种新型卵状碳包裹二氧化钛单晶在环境科学以及太阳能转换领域有着非常重要的用途。(The invention discloses a preparation method and application of an ovoid carbon-coated single-crystal titanium dioxide microsphere. The invention adopts a one-step hydrothermal method to synthesize amorphous carbon-coated titanium dioxide single crystal microspheres. The size of the microsphere is 1-1.5 microns, wherein the shell carbon layer is of an amorphous structure, and the core titanium dioxide is of an anatase single crystal structure. The method has the advantages of simple operation, simple process equipment, easily obtained raw materials, lower preparation cost, short reaction period and high repeatability. The material has outstanding performance in the aspect of photocatalytic degradation of organic pollutants. The novel ovoid carbon-coated titanium dioxide single crystal has very important application in the fields of environmental science and solar energy conversion.)

1. The ovoid carbon-coated titanium dioxide single-crystal microspheres are characterized in that the size of the microspheres is 1-1.5 microns, wherein a shell carbon layer is of an amorphous structure, and a core titanium dioxide is of an anatase phase.

2. A preparation method of an ovoid carbon-coated titanium dioxide single-crystal microsphere is characterized by comprising the following steps:

(1) deionized water (20-60 mL) and ascorbic acid (0.12-0.56g) are added into a polytetrafluoroethylene lining of a reaction kettle, and then a prepared titanium tetrafluoride solution (with the concentration of 30-53 mM) is added. Then, dropwise adding an HF solution (0.4-1.2 mL), uniformly stirring, and then placing the polytetrafluoroethylene lining into a high-temperature high-pressure reaction kettle. Reacting in an oven at the temperature of 150-220 ℃ for 3.5-48 hours, and taking out;

(2) and (5) after the reaction kettle is cooled to room temperature, sucking supernatant liquid and discarding. And centrifuging and collecting the lower-layer precipitate, washing with deionized water for 3 times, and then washing with absolute ethyl alcohol for 1 time. And after washing, putting the precipitate into an oven, and drying for 12 hours in vacuum at the temperature of 60-80 ℃ to obtain the carbon-coated single crystal titanium dioxide material which is black powder.

3. The use of the ovoid carbon-coated titanium dioxide monocrystallme spheres of claim 1, wherein the ovoid microspheres are used to photocatalytically degrade organic contaminants.

4. The use according to claim 3, characterized in that the method of application is as follows: under simulated sunlight, the carbon-coated titanium dioxide single crystal microspheres have photocatalytic degradation performance on methylene blue (10-30 mg/L).

Technical Field

The invention belongs to a carbon-coated titanium dioxide single crystal nano material with a core-shell structure, which is prepared by a one-step hydrothermal method, has excellent performance in the aspect of photocatalytic degradation of organic matters, and has potential application performance in other energy development and environmental protection fields.

Background

TiO₂Semiconductors are considered one of the best photocatalytic materials due to their long-term thermodynamic stability, strong oxidizing power and relative non-toxicity. In addition, phase-pure rutile and anatase TiO₂Polycrystalline materials with a band gap greater than 3eV result in a light absorption range limited to the ultraviolet region of the solar spectrum, which is such that in TiO₂The utilization rate of sunlight is low, and the application scenes of the material are limited. Over the last decades, much research has been done to improve TiO₂In an attempt to utilize a wider spectral range of sunlight. Carbon material and TiO₂The compounding is an effective method for improving the visible light absorption, and the carbon material has excellent conductivity, good chemical stability and good photoresponse. The combination of carbon materials with other materials can improve the conductivity and stability of the composite system, and has unique structure and low toxicity, excellent optical, thermal, electrochemical and mechanical properties. Wherein, TiO₂The composite system of the carbon-based material can integrate advantages, so that the composite material has higher stability, enhanced conductivity and optimized catalysis. TiO modified based on carbon material₂Has been widely described in the literature (e.g., graphene-TiO)₂Nanotube, carbon quantum dot/TiO₂Composite), however, the carbon layer encapsulates the TiO₂Single crystal structures have been rarely reported. Hair brushIn the Ming, a carbon-coated titanium dioxide single crystal nano material is designed, the material has a high-efficiency stable photocatalyst responding to visible light, and the material has good degradation capability on degradation of organic pollutants under simulated sunlight.

Disclosure of Invention

In view of the above problems, the present invention aims to provide a carbon-coated titanium dioxide single crystal nanomaterial with an egg-shaped structure, and a preparation method and an application thereof, wherein the preparation method is simple and has low cost. The prepared nano material has excellent photocatalytic degradation performance. The synthesis process does not need complex instruments, is simple to operate and is beneficial to large-scale production.

In order to achieve the purpose, the invention adopts the following technical scheme:

a carbon-coated titanium dioxide single crystal nano material with a core-shell structure is 1.0-1.5 microns in size, wherein a shell carbon layer is of an amorphous structure, and a core titanium dioxide is of an anatase phase single crystal structure.

A preparation method of a core-shell structure carbon-coated titanium dioxide single crystal nano material comprises the following steps:

(1) deionized water (20-60 mL) and ascorbic acid (0.12-0.56g) are added into a polytetrafluoroethylene lining of a reaction kettle, and then the prepared titanium tetrafluoride solution (with the concentration of 30-53 mM) is added into the reaction kettle. Then, adding an HF (0.4-1.2 mL) solution, uniformly stirring, placing the mixed solution in a high-temperature high-pressure reaction kettle, reacting at 150-220 ℃ for 3.5-48 hours, and taking out;

(2) and (4) after the reaction kettle is cooled to room temperature, sucking the supernatant liquid and discarding, collecting the lower precipitate and then carrying out centrifugal washing. Washing with deionized water for 3 times, and washing with anhydrous ethanol for 1 time. And after washing, putting the centrifugal tube filled with the precipitate into an oven, and drying for 12 hours in vacuum at the temperature of 60-80 ℃ to obtain the carbon-coated single crystal titanium dioxide material which is black powder, wherein the titanium dioxide is an anatase phase.

The carbon-coated titanium dioxide single crystal material is applied to photocatalytic degradation of organic matters.

The application method comprises the following steps: under simulated sunlight, the carbon-coated single crystal titanium dioxide single crystal microspheres have photocatalytic degradation performance on methylene blue (MB, 10-30 mg/L). The method comprises the steps of adding 10-30 mg of catalyst into 50-100 ml of dye, sampling the reaction solution once every five minutes under the illumination condition, measuring the change of the highest absorbance of methylene blue by using a UV-vis spectrometer, and testing results show that the concentration of the methylene blue in the solution is reduced by 55% under the simulated sunlight for 30 minutes.

The invention has the beneficial effects that:

(1) the method has the advantages that the method is simple, simple and convenient to operate, mild in condition, high in purity of target products, safe and nontoxic, and capable of being synthesized in large batch;

(2) the nano-sized carbon-coated titanium dioxide single crystal microsphere material is used for photocatalytic degradation of organic matters, and the result shows that the nano-sized carbon-coated titanium dioxide single crystal microsphere material has better photocatalytic degradation performance and better stability. The concentration of methylene blue in the solution decreased by 55% when irradiated under simulated sunlight for 30 minutes.

(3) In the preparation process, all reagents are commercial products and do not need further treatment;

(4) the synthetic method is simple, and the obtained material is easy to apply, is favorable for popularization and application in industrial production, and is used for sewage purification, pollutant photodegradation and the like.

Drawings

FIG. 1 is an electron photograph of an ovoid carbon-coated titanium dioxide single-crystal microsphere material prepared in example 1;

FIG. 2 is a graph of the performance of the ovoid carbon-coated titanium dioxide single-crystal microsphere material prepared in example 1 in photocatalytic degradation of methylene blue;

FIG. 3 is an X-ray diffraction pattern of the ovoid carbon-coated titanium dioxide single-crystal microsphere material prepared in example 1;

FIG. 4 is a transmission electron microscope image of the ovoid carbon-coated titanium dioxide single-crystal microsphere material prepared in example 1;

FIG. 5 is a scanning electron microscope image of the ovoid carbon-coated titanium dioxide single-crystal microsphere material prepared in example 1.

Detailed Description