Preparation method and application of carbon quantum dot/titanium dioxide composite photocatalyst

Abstract

The invention relates to a preparation method of a carbon quantum dot/titanium dioxide composite photocatalyst. The preparation method comprises the following steps: S1, titanium alkoxide and anhydrous ethanol are taken, and are stirred uniformly to obtain a liquid A; S2, glacial acetic acid, distilled water and anhydrous ethanol are taken, and are stirred well to obtain a liquid B, the pH value of the liquid B is adjusted to 2-3, carbon quantum dots are added to the liquid B, and mixing is performed to uniformity in order to obtain a liquid B containing carbon quantum dots; S3, the liquid A is dropwise added to the liquid B containing carbon quantum dots at a certain temperature, and the obtained mixture is uniformly stirred and reacted to obtain a sol; and S4, the sol obtained in step 3is dried, then is taken out after the drying is completed, is ground, and is calcined to obtain the carbon quantum dot/titanium dioxide composite photocatalyst. The composite photocatalyst prepared inthe invention has the advantages of good effect and uniformity in compounding of the carbon quantum dots and titanium dioxide, and excellent photocatalytic performance.

Description

technical field [0001] The invention relates to the technical field of photocatalysts, in particular to a preparation method and application of a carbon quantum dot / titanium dioxide composite photocatalyst. Background technique [0002] Titanium dioxide has many unique advantages, including stable chemical properties, excellent photoelectrochemical properties, light corrosion resistance, non-toxic to organisms, rich sources, and is an efficient photocatalyst, so it is often used for the degradation of organic pollutants, air Purification, sterilization and demister. Because titanium dioxide has a wide band gap of 3.2ev, it can only absorb ultraviolet light with a short wavelength, so its solar energy utilization rate is very low, only 3% to 5%, and due to the recombination of electrons and holes generated by photoexcitation, The light quantum efficiency is low, which limits its application in semiconductor photocatalysts. [0003] Studies have found that carbon nanomateria...

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Problems solved by technology

[0004] The invention patent (application number 201810046615.6) discloses a method for preparing and degrading formaldehyde by iron-doped carbon quantum dots / titanium dioxide composite photocatalyst. The method is to prepare quantum dots and titanium dioxide separately, and then compound the two. Inhomogeneous, there are greater limitations in practical applications

Invention patent (application number 201710146818.8) discloses a composite photocatalytic system CQDs-KNbO 3 Its preparation method and application provide a composite photocatalytic system CQDs-KNbO with strong redox activity 3 , can achieve hydrogen production while degrading organic pollutants under visible light irradiation, and the degradation speed of this invention is relatively slow

The invention patent (application number 201610344339.2) discloses the preparation method of carbon quantum dots / bismuth molybdate nanosheet composite photocatalytic material, which is used to degrade the organic pollutant rhodamine B. It is placed under hydrothermal conditions to form composites with related carbon quantum dot precursors, which makes bismuth molybdate easy to reunite under high temperature and high pressure, and it is easy to cause the composite to be successfully composited only on the outer surface, which makes it only suitable for use in the laboratory. It is difficult to actually produce; in addition, the toxicity of bismuth molybdate is much greater than that of titanium dioxide

The invention patent (application number 201510214659.1) discloses a preparation method of nitrogen-doped carbon quantum dots / titanium dioxide composite material, which is used for photocatalytic methanol decomposition to produce hydrogen. Aging and compounding can also easily lead to uneven compounding

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