Photocatalysis composite material of graphene coated titanium dioxide with twice growth

Abstract

The invention discloses a RGO / TiO2 (Reduced Graphene Dioxide / TiO2) photocatalysis composite material of graphene coated titanium dioxide with twice growth and belongs to the field of photocatalysis composite materials. Firstly, primary growth of TiO2 is regulated and controlled by adjusting the volume ratio of ethylene glycol to ethanol, types and concentrations of acids and hydrothermal reactiontime and temperatures, and thus unformed TiO2 is prepared; secondly, in secondary growth of TiO2, GO (Graphene Dioxide) is added to take a synergetic effect into play with the TiO2, and then GO is reduced into RGO. Under coating of the GO, the unfoamed TiO2 has a stable secondary growth environment and has the maximum contact area with graphene, the ultrahigh conductivity of the graphene is effectively utilized, hole compounding of TiO2 photoproduction electron pairs is greatly delayed, light absorption red shift is also resulted, and a light response area is widened to a visible light range.Meanwhile, pi-pi accumulation is allowed on a highly conjugated surface of graphene, so that the composite material has the characteristic that an aromatic compound is adsorbed preferably, and the properties of the material are greatly improved.

Description

technical field [0001] The content of the invention belongs to the field of photocatalytic composite materials, in particular to a graphene-wrapped TiO 2 Secondarily grown RGO / TiO 2 Photocatalytic composite material and its preparation method. Background technique [0002] Nanocrystalline titanium dioxide (TiO 2 ), due to its unique interface, high chemical stability, and photocatalytic properties, a large number of studies have applied it to the photocatalytic degradation of organic compounds in environmentally friendly materials. The redox chemistry of titanium dioxide makes it highly reactive with many other compounds. Even under light, TiO 2 It also has very good chemical stability, making it widely used as a photocatalyst. But TiO 2 The higher recombination rate of particle charge carriers leads to lower photocatalytic efficiency and activity. And titanium dioxide only absorbs light in the ultraviolet (UV) spectrum, limited to less than 10% of the solar spectrum....

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Problems solved by technology

[0005] The object of the present invention is to aim at existing graphene / TiO 2 TiO in composites 2 Mainly in the graphene sheet, agglomeration is easy to occur, and the surface area of ​​graphene is small, and the excellent electron mobility of graphene cannot be fully utilized, so that the problem of fast recombination of nano-titanium dioxide photogenerated electron-hole pairs cannot be effectively improved, and the active The problem of higher photocatalytic materials, a graphene-wrapped TiO 2 Secondarily grown RGO / TiO 2 Photocatalytic composite material, the composite material uses ethylene glycol as a structure-directing agent, changes the volume ratio of ethylene glycol to ethanol and the concentration of acid to regulate the TiO 2 growth, making it unstructured TiO in one growth 2 , and again hydrothermally cooperates with graphene oxide, that is, TiO 2 Surface hydrogen bonding removes different functional groups (such as -OH and -COOH groups) on the GO surface, while unshaped TiO 2 Also due to the secondary growth under its wrapping effect, it becomes a RGO / TiO with regular crystal shape, uniform dispersion in it, and maximized contact with its surface area. 2 Photocatalytic composite material, which greatly delays the recombination of photogenerated electron-hole pairs in titanium dioxide, and also regulates the 2 The bandgap width of the composite material is significantly improved and the photocatalytic activity of the composite is improved

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