Method for Preparing Molybdenum Doped Titanium Dioxide Thin Film by Sol-Gel

Abstract

The present invention discloses a method for preparing molybdenum doped titanium dioxide thin film by sol-gel, comprising following steps: preparing a mixed solution containing tetrabutyl titanate, adding a thickener to obtain solution I, preparing solution II containing ammonium molybdate solution, dropwise adding solution II into solution I and obtaining a titanium dioxide sol; dipping the titanium dioxide sol on the surface of a glass ball and oven drying, repeating such for several times, removing a solvent by vacuum drying, carrying out high-temperature calcination, keeping warm and obtaining molybdenum doped titanium dioxide thin film. The molybdenum doped titanium dioxide thin film prepared by the present invention has higher specific surface area, and the catalyst after modeling deposition has better transmissivity and porosity, large reaction contact area, high light efficiency and good photocatalytic effect.

Claims

1. A method for preparing molybdenum doped titanium dioxide thin film by sol-gel, characterized in that the method comprises following steps: (1) preparing a mixed solution by mixing tetrabutyl titanate, acetylacetone and anhydrous ethanol, stirring and mixing the mixed solution evenly; (2) adding a thickener into the mixed solution obtained in step (1), stirring to complete dissolution under 20-50° C. and obtaining a solution I; (3) mixing ammonium molybdate solution, deionized water and anhydrous ethanol, adjusting pH value to 4-6 by nitric acid, stirring sufficiently and mixing evenly, and obtaining a solution II; (4) dropwise adding the solution II obtained in step (3) into the solution I obtained in step (2) under vigorous stirring to hydrolyze the tetrabutyl titanate completely, after the completion, continually stirring for 2 hours and obtaining a faint yellow, uniform and transparent titanium dioxide sol; (5) immersing a glass ball into the titanium dioxide sol obtained in step (4) completely, loading the titanium dioxide sol on the glass ball surface by dipping coating method, oven drying in an air dry oven, immersing into the titanium dioxide sol again, oven drying again, repeating such for several times, taking multiple dipped and dried titanium dioxide sol, placing into a vacuum drying oven for completely drying, and evaporating a solvent completely; (6) placing the titanium dioxide sot obtained in step (5) in a muffle furnace and carrying out high-temperature calcination, taking out after cooling completely, and obtaining molybdenum doped titanium dioxide thin film.

2. The method tor preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that in step (1), the volume ratio of the tetrabutyl titanate, the acetylacetone and the anhydrous ethanol is 1:0.1-0.3:4-8.

3. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that the mixed solution is stirred for 0.5-1 hour by a magnetic stirrer under room temperature for stirring and mixing the mixed solution evenly in step (1).

4. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that the thickener in step (2) is one of polyethylene glycol and polyvinyl alcohol.

5. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that the thickener in step (2) is one of polyethylene glycol.

6. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that the dosage of the thickener in step (2) is 1-3 mL for each 10 mL tetrabutyl titanate.

7. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that in step 3, the concentration of the ammonium molybdate solution is 0.1 g/mL, and the mass concentration of the nitric acid is 65 wt %.

8. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that the dropwise adding speed in step (4) is 30-50 drops per minute.

9. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that the diameter of the glass ball in step (5) is 3-5 mm.

10. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that in step (5), the oven drying temperature for each time is 80° C., the oven drying time is 10 min, and the repeated times are 5-7; the drying temperature is 80° C. and drying time is 8-12 h.

11. The method for preparing molybdenum doped titanium dioxide thin film by sol-gel according to claim 1, characterized in that, a temperature of the high-temperature calcination in the step (6) is 300-600° C. and time for high-temperature calcination time is 3-6 hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention is further described with reference embodiments.

Embodiment 1

[0034] Preparation of 1% (n(Mo):n(Ti)=1%) molybdenum doped titanium dioxide thin film, and this embodiment comprises following steps:

[0035] (1) preparing a mixed solution by mixing 30 mL tetrabutyl titanate, 5 mL acetylacetone and 90 mL anhydrous ethanol, stirring and mixing the mixed solution evenly, and the stirring time is 0.5 hour;

[0036] (2) adding 5 mL thickener polyethylene glycol (PEG 200) into above stirred mixed solution, and stirring under 20-50° C. for complete dissolution and obtaining a solution I;

[0037] (3) mixing 1.55 mL and 0.1 g/mL ammonium molybdate solution, 6.2 mL deionized water and 45 mL anhydrous ethanol, adjusting pH value to 4-6 by dropwise adding nitric acid with concentration of 65%, stirring sufficiently and mixing evenly, and obtaining a solution II;

[0038] (4) dropwise adding the solution II into the solution I obtained in step (2 at a speed of 30-50 drops per minute under vigorous stirring to hydrolyze the tetrabutyl titanate completely, continually stirring for 2 hours and obtaining faint yellow, uniform and transparent titanium dioxide sol;

[0039] (5) immersing 3-5 mm glass ball into the above sol completely, loading the sol on the surface of the glass ball by dipping coating method, drying for 10 min in the air dry oven under 80° C., immersing dried glass ball into above sol, taking out and drying for 10 min in the air dry oven under 80° C. again, repeating such for 5-7 times, taking the obtained titanium dioxide sol down, placing in the air dry oven under 80° C. for completely drying for 8-12 hours and evaporating the solvent completely;

[0040] (6) placing the titanium dioxide sol obtained in step (5) in the muffle furnace, high-temperature calcining under 300-600° C. and keeping warm for 3-6 hours, taking out after cooling sufficiently, and obtaining 1% molybdenum doped titanium dioxide thin film.

Embodiment 2

[0041] Preparation of 2% (n(Mo):n(Ti)=2%) molybdenum doped titanium dioxide thin film, and this embodiment comprises following steps:

[0042] (1) preparing a mixed solution by mixing 30 mL tetrabutyl titanate, 5 mL acetylacetone and 90 mL anhydrous ethanol, stirring and mixing the mixed solution evenly, and the stirring time is 0.5 hour;

[0043] (2) adding 5 mL thickener polyethylene glycol (PEG200) into above stirred mixed solution, and stirring under 20-50° C. for completely dissolution, and obtaining a solution I;

[0044] (3) mixing 3.1 mL and 0.1 g/mL ammonium molybdate solution, 4.65 mL deionized water and 45 mL anhydrous ethanol, adjusting pH value to 4-6 by dropwise adding nitric add with concentration of 65%, stirring sufficiently and mixing evenly, and obtaining a solution II;

[0045] (4) dropwise adding the solution II into the solution I obtained in step (2) at a speed of 30-50 drops per minute under vigorous stirring to hydrolyze the tetrabutyl titanate completely, continually stirring for 2 hours and obtaining faint yellow, uniform and transparent titanium dioxide sol;

[0046] (5) immersing 3-5 mm glass ball into above sol completely, loading the sol on the surface of the glass ball by dipping coating method, drying for 10 min in the air dry oven under 80° C., immersing dried glass ball into above sol, taking out and drying for 10 min in the air dry oven under 80° C. again, repeating such for 5-7 times, placing the obtained titanium dioxide sol in the air dry oven under 80° C. for completely drying for 8-12 hours and evaporating the solvent completely;

[0047] (6) placing the titanium dioxide sol obtained in step (5) in the muffle furnace, high-temperature calcining under 300-600° C. and keeping warm for 3-6 hours, taking out after cooling sufficiently, and obtaining 2% molybdenum doped titanium dioxide thin film.

Embodiment 3

[0048] Preparation of 3% (n(Mo):n(Ti)=3%) molybdenum doped titanium dioxide thin film, and this embodiment comprises following steps:

[0049] (1) preparing a mixed solution by mixing 30 mL tetrabutyl titanate, 5 mL acetylacetone and 90 mL anhydrous ethanol, stirring and mixing the mixed solution evenly, and the stirring time is 0.5 hour;

[0050] (2) adding 5 mL thickener polyethylene glycol (PEG200) into above stirred mixed solution, and stirring under 20-50° C. for completely dissolution, and obtaining a solution I;

[0051] (3) mixing 4.65 mL, and 0.1 g/ml, ammonium molybdate solution, 3.1 ml deionized water and 45 mL anhydrous ethanol, adjusting pH value to 4-6 by dropwise adding nitric acid with concentration of 65%, stirring sufficiently and mixing evenly, and obtaining a solution II;

[0052] (4) dropwise adding the solution II into the solution I obtained in step (2) at a speed of 30-50 drops per minute under vigorous stirring to hydrolyze the tetrabutyl titanate completely, continually stirring for 2 hours and obtaining faint yellow, uniform and transparent titanium dioxide sol;

[0053] (5) immersing 3-5 mm glass ball into the above sol completely, loading the sol on the surface of the glass ball by dipping coating method, drying for 10 min in the air dry oven under 80° C., immersing dried glass bail into above sol, taking out and drying for 10 min in the air dry oven under 80° C. again, repeating such for 5-7 times, placing the obtained titanium dioxide sol in the air dry oven under 80° C. for completely drying for 8-12 hours and evaporating the solvent completely;

[0054] (6) placing the titanium dioxide sol obtained in step (5) in the muffle furnace, high-temperature calcining under 300-600° C. and keeping warm for 3-6 hours, taking out after cooling sufficiently, and obtaining 3% molybdenum doped titanium dioxide thin film.

Embodiment 4

[0055] Preparation of 3.5% (n(Mo):n(Ti)=3.5%) molybdenum doped titanium dioxide thin film, and this embodiment comprises following steps:

[0056] (1) preparing a mixed solution by mixing 30 mL tetrabutyl titanate, 5 mL acetylacetone and 90 mL anhydrous ethanol, stirring and mixing the mixed solution evenly, and the stirring time is 0.5 hour;

[0057] (2) adding 5 mL thickener polyethylene glycol (PEG200) into above stirred mixed solution, and stirring under 20-50° C. for completely dissolution, and obtaining a solution I;

[0058] (3) mixing 5.4 mL and 0.1 g/mL ammonium molybdate solution, 2.35 mL deionized water and 45 mL anhydrous ethanol, adjusting pH value to 4-6 by dropwise adding nitric acid with concentration of 65%, stirring sufficiently and mixing evenly, and obtaining a solution II;

[0059] (4) dropwise adding the solution II into the solution I obtained in step (2) at a speed of 30-50 drops per minute under vigorous stirring to hydrolyze the tetrabutyl titanate completely, continually stirring for 2 hours and obtaining faint yellow, uniform and transparent titanium dioxide sol;

[0060] (5) immersing 3-5 mm glass ball into the above sol completely, loading the sol on the surface of the glass ball by dipping coating method, drying for 10 min in the air dry oven under 80° C., immersing dried glass ball into above sol, taking out and drying for 10 min in the air dry oven under 80° C. again, repeating such for 5-7 times, taking the obtained titanium dioxide sol down and placing in the air dry oven under 80° C. for completely drying for 8-12 hours and evaporating the solvent completely;

[0061] (6) placing the titanium dioxide sol obtained in step (5) in the muffle furnace, high-temperature calcining under 300-600° C. and keeping warm for 3-6 hours, taking out after cooling sufficiently, and obtaining 3.5% molybdenum doped titanium dioxide thin film.

Embodiment 5

[0062] Preparation of 5% (n(Mo):n(Ti)=5%) molybdenum doped titanium dioxide thin film, and this embodiment comprises following steps:

[0063] (1) preparing into a mixed solution by mixing 30 mL tetrabutyl titanate, 5 mL acetylacetone and 90 mL anhydrous ethanol, stirring and mixing the mixed solution evenly, and the stirring time is 0.5 hour;

[0064] (2) adding 5 mL thickener polyethylene glycol (PEG200) into above stirred mixed solution, and stirring under 20-50° C. for completely dissolution, and obtaining a solution I;

[0065] (3) mixing 7.75 mL and 0.1 g/mL ammonium molybdate solution, 45 mL anhydrous ethanol, adjusting pH value to 4-6 by dropwise adding nitric acid with concentration of 65%, stirring sufficiently and mixing evenly, and obtaining a solution II;

[0066] (4) dropwise adding the solution Il into the solution I obtained in step (2) at a speed of 30-50 drops per minute under vigorous stirring to hydrolyze the tetrabutyl titanate completely, continually stirring for 2 hours and obtaining faint yellow, uniform and transparent titanium dioxide sol;

[0067] (5) immersing 3-5 mm glass ball into the above sol completely, loading the sol on the surface of the glass ball by dipping coating method, drying for 10 min in the air dry oven under 80° C., immersing dried glass ball into above sol, taking out and drying for 10 min in the air dry oven under 80° C. again, repeating such for 5-7 times, taking the obtained titanium dioxide sol and placing in the air dry oven under 80° C. for completely drying for 8-12 hours and evaporating the solvent completely;

[0068] (6) placing the titanium dioxide sol obtained in step (5) in the muffle furnace, high-temperature calcining under 300-600° C. and keeping warm for 3-6 hours, taking out after cooling sufficiently, and obtaining 5% molybdenum doped titanium dioxide thin film.

Embodiment 6

[0069] Application of molybdenum doped titanium dioxide thin film in degrading volatile organic compounds (VOCs).

[0070] An experiment of photocatalytic degradation of toluene is carried out by simulating that main ingredients containing VOCs in the air are 78% nitrogen (N.sub.2) and 21% oxygen (O.sub.2), and toluene concentration is 10 ppm and placing the catalyst into the specially-made bushing type photocatalytic simulation testing apparatus, and the catalyst is molybdenum doped titanium dioxide thin film prepared in embodiment 2 under the condition that the relative humidity is 20-60%, operating temperature is 20-25° C., and simulative light source is 16 W and 254 nm. Results show that the degradation efficiency is higher than 94.6%, and the catalytic activity of 2% molybdenum doped titanium dioxide thin film is 1.48 times than that of pure titanium dioxide catalyst.

[0071] Above disclosure are some preferred embodiments to carry out the present invention, and they are merely some examples of the technical concept, and the present invention is not limited thereto. Any variations and equivalents made by those skilled in the art without departing from the spirit and scope of the technical proposal shall fall into the protection scope of the present invention.