Background technology
Along with the enhancing of mankind's environmental consciousness and environmental protection legislation demands are increasingly strict, the pollution problem in chemical industry has become public social concern.People wish to adopt nontoxic raw material, produce and eco-friendly product.The research of the catalyzer of present degradable organic pollutant is just becoming the focus of people's concern, and it is stated in realization in object and plays a part key.
At present, Photocatalitic Technique of Semiconductor is subject to the common concern of various countries' environment and energy research person.The development of photocatalysis oxidation technique brings new development potentiality to the process of environmental pollutant and reply energy dilemma, becomes most active research field in waste water, waste-gas cleaning process and hydrogen producing technology.But TiO
2restriction by energy gap (Eg=3.2eV) can only absorb account for sunlight less than 5% UV-light (λ <387nm), very low to solar energy utilization ratio.Therefore, development research is the key problem in technology improving solar energy utilization ratio and solve current problem compared with the novel visible catalyst of low energy gap width.But α-Fe
2o
3energy gap is narrow, stable performance, nontoxic, cheap, the response of good photoelectrochemistry is all shown to UV-light and visible ray, sunlight utilising efficiency is high, be widely used in degraded environmental pollutant, waste gas and the field such as photolysis water hydrogen, oxygen, be the very promising visible light catalyst of one, become a study hotspot in photocatalysis field in recent years.As the α-Fe of semi-conductor
2o
3with TiO
2compare, its band gap (being generally about 2.2eV) compares TiO
2band gap (3.2eV) is narrow, and the wavelength (maximum excitation wavelength 560nm) of its photoresponse is than TiO
2uV district absorbing wavelength (380nm) long, therefore α-Fe
2o
3the utilization ratio of sun power is increased, there is in visible region very strong light absorpting ability, the solar energy of about 30% can be absorbed.
The method preparing ferric oxide conventional has roasting method, the precipitator method, sol-gel method, hydrolysis method and hydrothermal method.Wherein first three methods all needs the calcining through comparatively high temps, and synthesized powder reuniting is serious, gained powder dispersibility difference and the particle not well-regulated pattern of tool.Only have latter two method, namely hydrolysis method and hydrothermal method can realize the control synthesis of ferric oxide particles pattern.Hydrolysis method is obtained monodispersed particle easily, but the production cycle is long, productive rate is low, and energy consumption is high.And the nanometer α-Fe of water heat transfer
2o
3particle purity is very high, not containing other impurity; Simultaneously hydrothermal synthesis method raw material is easy to get, product grain good crystalline, good dispersity, morphology controllable advantage of lower cost, output is high.So hydrothermal synthesis method is a kind of very important synthesis of nano α-Fe
2o
3the method of particle.
At present, granule-morphology is only had to be spherical both at home and abroad, octahedra, spindle body, the α-Fe of ellipsoidal particle
2o
3the report of nano-powder synthesis, there is not yet disc-shaped α-Fe
2o
3the report of nano-powder.
Summary of the invention
The object of the present invention is to provide a kind of disc-shaped α-Fe
2o
3photocatalyst and its preparation method and application, this preparation method's technique is simple, easy to operate, obtained disc-shaped α-Fe
2o
3photocatalyst has good photocatalytic activity, can be applied to degradation of organic substances under ultraviolet light.
For achieving the above object, the technical solution used in the present invention is:
A kind of disc-shaped α-Fe
2o
3the preparation method of photocatalyst, comprises the following steps:
Step 1: by FeCl
36H
2o is soluble in water, stirs, and obtains solution A; By NH
4vO
3be dissolved in the water of 80 ~ 95 DEG C, stir, obtain solution B; Be that solution B joins in solution A by 1:1 according to the mol ratio of Fe element and V element, stir, obtain mixed solution;
Step 2: the pH value regulating mixed solution is 10 ~ 12;
Step 3: put into hydrothermal reaction kettle by have adjusted the mixed solution after pH value, sealing hydrothermal reaction kettle;
Step 4: hydrothermal reaction kettle is put into heating installation, from room temperature to 210 ~ 230 DEG C, then at 210 ~ 230 DEG C of insulation 15 ~ 17h, then naturally cools to room temperature;
Step 5: the precipitation generated in hydrothermal reaction kettle taken out, washing, drying, obtain disc-shaped α-Fe
2o
3photocatalyst.
FeCl in described solution A
36H
2the concentration of O is 0.08 ~ 0.12mol/L, NH in solution B
4vO
3concentration be 0.08 ~ 0.12mol/L.
Required time that stirs in described step 1 is 20 ~ 30min.
Regulate the pH value of mixed solution in described step 2 by NaOH solution, the concentration of NaOH solution is 3 ~ 5mol/L.
In described step 3, the compactedness of hydrothermal reaction kettle is 60% ~ 70%.
In described step 4 with the time of 40 ~ 45min from room temperature to 210 ~ 230 DEG C.
Washing in described step 5, for using water and dehydrated alcohol washing precipitation respectively, is neutral to elutant.
Drying in described step 5 be by washing after be deposited in 60 ~ 70 DEG C at dry 10 ~ 12h.
Described disc-shaped α-Fe
2o
3disc-shaped α-the Fe that the preparation method of photocatalyst obtains
2o
3photocatalyst, its pattern is disc-shaped, and crystal formation is water chestnut square structure.
Described disc-shaped α-Fe
2o
3disc-shaped α-the Fe that the preparation method of photocatalyst obtains
2o
3the application of photocatalyst degradation of organic substances under ultraviolet light.
Relative to prior art, beneficial effect of the present invention is:
Disc-shaped α-Fe provided by the invention
2o
3the preparation method of photocatalyst, with Iron(III) chloride hexahydrate (FeCl
36H
2and ammonium meta-vanadate (NH O)
4vO
3) be raw material, be under the alkaline environment of 10 ~ 12 in pH value, adopt hydrothermal method to prepare disc-shaped α-Fe
2o
3photocatalyst.The method technique is simple, easy to operate, reaction conditions is gentle, preparation cycle is short, production efficiency is high, and in preparation process α-Fe
2o
3do not reunite, the controlled range of its particle diameter is wider.And the pH value of mixed solution can affect obtained α-Fe in the present invention
2o
3the photocatalytic activity of photocatalyst, therefore, it is possible to regulate and control the pH value of mixed solution thus regulate and control obtained α-Fe
2o
3the photocatalytic activity of photocatalyst, has the advantage of target product structure and morphology controllable.
α-the Fe that the present invention obtains
2o
3photocatalyst is disc-shaped pattern, uniform particle sizes, and its diameter is about 800nm, and its crystal formation is water chestnut square structure, and obtained α-Fe
2o
3photocatalyst shows good photocatalytic activity under UV-irradiation, can under ultraviolet light degradation of organic substances aspect application.
Embodiment
Below in conjunction with specific embodiments and the drawings, preparation method of the present invention is described in further detail.
Embodiment 1:
Step 1: by FeCl
36H
2o is dissolved in deionized water, stirring 30min to stirring, obtaining solution A, FeCl in solution A
36H
2the concentration of O is 0.08mol/L; By NH
4vO
3be dissolved in the deionized water of 80 DEG C, stir 30min to stirring, obtaining solution B, NH in solution B
4vO
3concentration be 0.08mol/L; Be that solution B dropwise joins in solution A by 1:1 according to the mol ratio of Fe and V, stir 30min to stirring, obtaining mixed solution;
Step 2: regulate the pH value of mixed solution to be 10 by the NaOH solution that concentration is 4mol/L;
Step 3: will have adjusted the mixed solution after pH value and put into the polytetrafluoroethyltank tank of hydrothermal reaction kettle, the packing ratio controlling hydrothermal reaction kettle is 70%, then seals hydrothermal reaction kettle;
Step 4: hydrothermal reaction kettle is put into high temperature oven, with time of 45min from room temperature to 220 DEG C, then at 220 DEG C of insulation 16h, then naturally cools to room temperature;
Step 5: the precipitation that generates in hydrothermal reaction kettle is taken out, with the washing precipitation 3 times respectively of deionized water and dehydrated alcohol, to elutant in neutral, then by after washing be deposited in 60 DEG C at dry 12h, obtain disc-shaped α-Fe
2o
3photocatalyst.
Embodiment 2:
Step 1: by FeCl
36H
2o is dissolved in deionized water, stirring 30min to stirring, obtaining solution A, FeCl in solution A
36H
2the concentration of O is 0.08mol/L; By NH
4vO
3be dissolved in the deionized water of 85 DEG C, stir 30min to stirring, obtaining solution B, NH in solution B
4vO
3concentration be 0.08mol/L; Be that solution B dropwise joins in solution A by 1:1 according to the mol ratio of Fe and V, stir 30min to stirring, obtaining mixed solution;
Step 2: regulate the pH value of mixed solution to be 12 by the NaOH solution that concentration is 4mol/L;
Step 3: will have adjusted the mixed solution after pH value and put into the polytetrafluoroethyltank tank of hydrothermal reaction kettle, the packing ratio controlling hydrothermal reaction kettle is 65%, then seals hydrothermal reaction kettle;
Step 4: hydrothermal reaction kettle is put into high temperature oven, with time of 45min from room temperature to 220 DEG C, then at 220 DEG C of insulation 16h, then naturally cools to room temperature;
Step 5: the precipitation that generates in hydrothermal reaction kettle is taken out, with the washing precipitation 3 times respectively of deionized water and dehydrated alcohol, to elutant in neutral, then by after washing be deposited in 70 DEG C at dry 10h, obtain disc-shaped α-Fe
2o
3photocatalyst.
Fig. 1 is disc-shaped α-Fe prepared by the present invention
2o
3the SEM figure of photocatalyst, as can be seen from the figure its pattern is disc-shaped, uniform particle sizes, and its diameter is about 800nm.
Fig. 2 is the disc-shaped α-Fe that the present invention is prepared at various ph values
2o
3the XRD spectra of photocatalyst, disc-shaped α-Fe when wherein a is embodiment 1 obtained pH=10
2o
3the XRD figure of photocatalyst; Disc-shaped α-Fe when b is embodiment 2 obtained pH=12
2o
3the XRD figure of photocatalyst.As can be seen from Figure 2, the disc-shaped α-Fe prepared under different pH value
2o
3the diffraction peak of photocatalyst is all consistent with PDF card (JCPDS No.33-0664), is the α-Fe of water chestnut square structure
2o
3.
Embodiment 3:
Step 1: by FeCl
36H
2o is dissolved in deionized water, stirring 30min to stirring, obtaining solution A, FeCl in solution A
36H
2the concentration of O is 0.08mol/L; By NH
4vO
3be dissolved in the deionized water of 90 DEG C, stir 30min to stirring, obtaining solution B, NH in solution B
4vO
3concentration be 0.08mol/L; Be that solution B dropwise joins in solution A by 1:1 according to the mol ratio of Fe and V, stir 30min to stirring, obtaining mixed solution;
Step 2: regulate the pH value of mixed solution to be 10 by the NaOH solution that concentration is 4mol/L;
Step 3: will have adjusted the mixed solution after pH value and put into the polytetrafluoroethyltank tank of hydrothermal reaction kettle, the packing ratio controlling hydrothermal reaction kettle is 60%, then seals hydrothermal reaction kettle;
Step 4: hydrothermal reaction kettle is put into high temperature oven, with time of 45min from room temperature to 220 DEG C, then at 220 DEG C of insulation 16h, then naturally cools to room temperature;
Step 5: the precipitation that generates in hydrothermal reaction kettle is taken out, with the washing precipitation 3 times respectively of deionized water and dehydrated alcohol, to elutant in neutral, then by after washing be deposited in 65 DEG C at dry 11h, obtain disc-shaped α-Fe
2o
3photocatalyst.
Embodiment 4:
Step 1: by FeCl
36H
2o is dissolved in deionized water, stirring 30min to stirring, obtaining solution A, FeCl in solution A
36H
2the concentration of O is 0.08mol/L; By NH
4vO
3be dissolved in the deionized water of 95 DEG C, stir 30min to stirring, obtaining solution B, NH in solution B
4vO
3concentration be 0.08mol/L; Be that solution B dropwise joins in solution A by 1:1 according to the mol ratio of Fe and V, stir 30min to stirring, obtaining mixed solution;
Step 2: regulate the pH value of mixed solution to be 12 by the NaOH solution that concentration is 4mol/L;
Step 3: will have adjusted the mixed solution after pH value and put into the polytetrafluoroethyltank tank of hydrothermal reaction kettle, the packing ratio controlling hydrothermal reaction kettle is 65%, then seals hydrothermal reaction kettle;
Step 4: hydrothermal reaction kettle is put into high temperature oven, with time of 45min from room temperature to 220 DEG C, then at 220 DEG C of insulation 16h, then naturally cools to room temperature;
Step 5: the precipitation that generates in hydrothermal reaction kettle is taken out, with the washing precipitation 3 times respectively of deionized water and dehydrated alcohol, to elutant in neutral, then by after washing be deposited in 70 DEG C at dry 10h, obtain disc-shaped α-Fe
2o
3photocatalyst.
Fig. 3 is the disc-shaped α-Fe that the present invention is prepared at various ph values
2o
3photocatalyst under ultraviolet light to the degradation rate curve of rhodamine B, the C/C of ordinate zou in Fig. 3
0for the ratio of the concentration after certain rhodamine B degraded and its starting point concentration in moment.Disc-shaped α-Fe when wherein a is embodiment 3 obtained pH=10
2o
3photocatalyst is to the degradation rate curve of rhodamine B, and after UV-irradiation 180min, the degradation rate of rhodamine B is 66%; Disc-shaped α-Fe when b is embodiment 4 obtained pH=12
2o
3photocatalyst is to the degradation rate curve of rhodamine B, and after UV-irradiation 180min, the degradation rate of rhodamine B is 70%; C is the spontaneous degradation curve of pure rhodamine B.As can be seen from Figure 3, under UV-irradiation, there is the disc-shaped α-Fe of water chestnut square structure
2o
3the photocatalytic activity of photocatalyst is also progressively increasing, wherein according to disc-shaped α-Fe prepared by embodiment 4 along with the increase of pH value
2o
3the degradation rate of photocatalyst to rhodamine B is the highest.Therefore the disc-shaped α-Fe that obtains of the present invention
2o
3photocatalyst can be applied to degradation of organic substances under ultraviolet light.
Embodiment 5:
Step 1: by FeCl
36H
2o is dissolved in deionized water, stirring 20min to stirring, obtaining solution A, FeCl in solution A
36H
2the concentration of O is 0.12mol/L; By NH
4vO
3be dissolved in the deionized water of 88 DEG C, stir 25min to stirring, obtaining solution B, NH in solution B
4vO
3concentration be 0.12mol/L; Be that solution B dropwise joins in solution A by 1:1 according to the mol ratio of Fe and V, stir 25min to stirring, obtaining mixed solution;
Step 2: regulate the pH value of mixed solution to be 11 by the NaOH solution that concentration is 3mol/L;
Step 3: will have adjusted the mixed solution after pH value and put into the polytetrafluoroethyltank tank of hydrothermal reaction kettle, the packing ratio controlling hydrothermal reaction kettle is 62%, then seals hydrothermal reaction kettle;
Step 4: hydrothermal reaction kettle is put into high temperature oven, with time of 40min from room temperature to 230 DEG C, then at 230 DEG C of insulation 15h, then naturally cools to room temperature;
Step 5: the precipitation that generates in hydrothermal reaction kettle is taken out, with the washing precipitation 3 times respectively of deionized water and dehydrated alcohol, to elutant in neutral, then by after washing be deposited in 62 DEG C at dry 11.5h, obtain disc-shaped α-Fe
2o
3photocatalyst.
Embodiment 6:
Step 1: by FeCl
36H
2o is dissolved in deionized water, stirring 25min to stirring, obtaining solution A, FeCl in solution A
36H
2the concentration of O is 0.10mol/L; By NH
4vO
3be dissolved in the deionized water of 92 DEG C, stir 20min to stirring, obtaining solution B, NH in solution B
4vO
3concentration be 0.10mol/L; Be that solution B dropwise joins in solution A by 1:1 according to the mol ratio of Fe and V, stir 20min to stirring, obtaining mixed solution;
Step 2: regulate the pH value of mixed solution to be 10.5 by the NaOH solution that concentration is 5mol/L;
Step 3: will have adjusted the mixed solution after pH value and put into the polytetrafluoroethyltank tank of hydrothermal reaction kettle, the packing ratio controlling hydrothermal reaction kettle is 68%, then seals hydrothermal reaction kettle;
Step 4: hydrothermal reaction kettle is put into high temperature oven, with time of 43min from room temperature to 210 DEG C, then at 210 DEG C of insulation 17h, then naturally cools to room temperature;
Step 5: the precipitation that generates in hydrothermal reaction kettle is taken out, with the washing precipitation 3 times respectively of deionized water and dehydrated alcohol, to elutant in neutral, then by after washing be deposited in 68 DEG C at dry 10.5h, obtain disc-shaped α-Fe
2o
3photocatalyst.
The foregoing is only one embodiment of the present invention, it not whole or unique embodiment, the conversion of those of ordinary skill in the art by reading specification sheets of the present invention to any equivalence that technical solution of the present invention is taked, is claim of the present invention and contains.