Energy-converting photocatalysis nanophase material and preparation method thereof

Abstract

The invention discloses an energy-converting photocatalysis nano material and a preparation method thereof. Firstly, 0.02-3.5 mol.L<-1> titanium tetrachloride is used as the raw material, and one or two oxides of the rare earth elements of Yb, Er, Ho and Tm are mixed with the titanium tetrachloride. The mixed rare earth oxides account for 0.01-20 percent of the total weight. The mixed solution is subject to hydrolysis for 20-480 minutes at a temperature of 20-90 DEG C. Then, the mixed solution is extracted by means of an organic extraction method with organic amine so as to remove the Cl<-> in the solution and obtain anatase type nanometer titanium dioxide gel containing rare earth elements, and the titanium dioxide gel is aged for 2-48 hours. Finally, the titanium dioxide gel undergoes hydrothermal crystallization at a temperature of 120-240 DEG C so as to obtain the nano energy-converting photocatalysis material. In the invention, through energy conversion, part of the visible light, which is absorbed by the anatase type titanium dioxide, is converted into ultraviolet energy to be absorbed, without reducing forbidden gap, thereby improving the utilization rate of the visible light by a titanium dioxide photocatalyst, being capable of realizing the industrialization production of titanium tetrachloride hydrolysis and avoiding particle aggregation possibly generated by high-temperature calcining.

Description

technical field [0001] The invention relates to a preparation method of anatase nano titanium dioxide with photocatalytic activity under visible light. Background technique [0002] Anatase-type titanium dioxide (TiO 2 ) has photocatalytic properties. When the particle size of nano-titanium dioxide is smaller than a certain critical size, the oxidation ability of photogenerated electrons and holes is greatly improved, and most organic substances can be oxidized. At the same time, titanium dioxide has the advantages of stable chemical properties, non-toxic and non-polluting, and is widely used in indoor air purification, harmless treatment of natural water bodies and industrial wastewater. [0003] During the preparation and use of anatase nano-titanium dioxide as a photocatalyst, there are two key technical issues: one is that the band gap of anatase titanium dioxide is 3.2 eV, and the wavelength of light that absorbs energy that matches the band gap is at In the ultraviol...

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Problems solved by technology

[0003] During the preparation and use of anatase nano-titanium dioxide as a photocatalyst, there are two key technical issues: one is that the band gap of anatase titanium dioxide is 3.2 eV, and the wavelength of light that absorbs energy that matches the band gap is at In the ultraviolet region (λ<387nm), the photocatalytic efficiency in natural light is reduced (the wavelength of sunlight is 460-500nm); the second is in the preparation of anatase nano-titanium dioxide method, if the higher cost of titanic acid is used In the sol-gel method with butyl fat as the raw material, the gel needs to be calcined at 500-600°C to complete the crystallization, and the aggregation of nanoparticles will inevitably occur; if the low-cost titanium tetrachloride hydrolysis method or titanium sulfate precipitation is used preparation method, it is necessary to repeatedly wash the amorphous titanium dioxide (orthotitanic acid sol) and then calcinate and crystallize it at 500-600°C. Very difficult to promote in industrial production

The above-mentioned published patent can certainly reduce the bandgap width of titanium dioxide by doping, so that the matching absorption band can be partially red-shifted to the visible light band, but its defect is that the reduction of the bandgap width will reduce the redox potential of titanium dioxide and weaken its oxidation. ability to decompose organic matter

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