Preparation method of photo catalyst by transition metal halide molten salt and use thereof

Abstract

A preparation method of photo catalyst by transition metal halide molten salt and use thereof, wherein low-valence titanium complexes stable in air and water are used as a Ti source, transition metal halide is used as molten salt, mixing the Ti source and the molten salt as per a certain mole ratio and grinding, heating at air atmosphere until no lower than a fusion point of the molten salt, keeping the molten salt in a state of melting, maintaining the temperature, washing with water, and reduced TiO.sub.2−x rich in Ti.sup.3+ and Ov is obtained in one-step melting reaction. Deficiencies that multiple steps are involved for preparing conventional defect titanium dioxide or use of inflammable and explosive reducing gases or other dangerous reducing agents or oxidizing agents have been addressed; and the defect that the Ti source is liable to be dissolved in organic and other solvents is fully avoided.

Claims

1. A preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt, comprising: using low-valence complexes stable in air and water as a Ti source, using transition metal halide as molten salt, mixing the Ti source and the molten salt as per a mole ratio, grinding, heating in air atmosphere until no less than a fusion point of the molten salt, keeping the transition metal halide in a molten state; maintaining the temperature for 2-8 h, separating by washing with water, and a reduced TiO.sub.2−x photo catalyst with an excellent visible response capability is obtained.

2. The preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt according to claim 1, wherein the low-valence complexes stable in air and water are any one or combination of TiH.sub.2, TiO, Ti.sub.2O.sub.3 and TiCN, the transition metal halide is any one or combination of CuCl, CuBr, ZnBr.sub.2, FeCl.sub.3, CoCl.sub.2 and CoBr.sub.2.

3. The preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt according to claim 1, wherein the Ti source and the molten salt are mixed at a mole ratio of 1:1-1:8.

4. The preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt according to claim 1, wherein a preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt comprises following steps: step (1): weighing the Ti source and the transition metal halide, mixing and grinding fully in a mortar, transferring the same to a melting pot, putting into a muffle furnace, heating to 430-600° C. at a certain heating rate; step (2): maintaining the temperature for a certain period of time, turning off power supply, furnace cooling until reaching ambient temperature, taking out the melting pot, putting hot water in, treating by ultrasonic treatment or mixing; and step (3): filtering and washing a product, vacuum drying, and reduced TiO.sub.2−x is obtained.

5. The preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt according to claim 4, wherein the Ti source in the step (1) is TiO, a quantity weighed is 1 g; the transition metal halide is CuCl, a quantity weighed is 4 g; the mixing and grinding time is 10-30 minutes and the heating rate is 2-10° C./min;

6. The preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt according to claim 4, wherein in the step (2), time for maintaining the temperature is 2-8 h, and temperature of the hot water is 40-80° C.; in the step (2), treating by ultrasonic treatment or mixing comprises: treating by ultrasonic treatment for 10-30 minutes in an ultrasonic washing machine with a frequency of 25 kHz-130 kHz or mixing magnetically and dissolving for 10-30 minutes at a mixing rate of no less than 100 r/min; in the step (3), filtering and washing comprises: filtering the product in a common way or in vacuum, separating the product and aqueous solution of the molten salt, and washing for 3-6 times with distilled water during filtering; and in the step (3), a temperature for vacuum drying is 30-120° C. and time for vacuum drying is 2-12 h.

7. The preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt according to claim 1, wherein TiO is replaced with TiH.sub.2, Ti.sub.2O.sub.3 and TiCN, a mass of CuCl varies from 2 g to 8 g, and can be replaced with CuBr, ZnBr.sub.2, FeCl.sub.3, CoCl.sub.2, and CoBr.sub.2, and lowest temperature after heating shall be no lower than a fusion point of corresponding molten salt, no higher than a boiling point or decomposition temperature thereof; when CuCl is chosen as the molten salt, the lowest temperature after heating shall be no less than 426° C., and the highest temperature no higher than 1490° C.; when ZnBr.sub.2 is chosen as the molten salt, the lowest temperature after heating shall be no less than 395° C. and the highest temperature no higher than 650° C.; time for maintaining the temperature is 2-8 h, CuCl and CuBr shall be mixed and washed in hot water and other molten salts can be mixed in water of ambient temperature and have the molten salts dissolved or dissolution can be expedited under ultrasonic conditions.

8. The reduced titanium dioxide photo catalyst by transition metal halide molten salt obtained by the foregoing preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt as defined in claim 1.

9. Use of the reduced titanium dioxide photo catalyst by transition metal halide molten salt as defined in claim 8 in catalyzing and degrading organic pollutants in waste water and waste gases under sunlight, water treatment and disinfection, sterilization and treatment of indoor air.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings are incorporated in the specification and form a part of the specification, wherein embodiments of the present disclosure are given, and are used together with the specification for explaining principles of the present disclosure.

[0033] FIG. 1 is a flowchart diagram showing the preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt provided in an embodiment of the present invention.

[0034] FIG. 2 is an XRD pattern showing a product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source, CuCl as molten salt, wherein a mass ratio between TiH.sub.2 and CuCl is 1:4.

[0035] FIG. 3 is a TEM image of the product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source and CuCl as molten salt, wherein a mass ratio between TiH.sub.2 and CuCl is 1:4.

[0036] FIG. 4 is a diagram showing Ti 2p XPS results of the product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source and CuCl as molten salt, wherein a mass ratio between TiH.sub.2 and CuCl is 1:4.

[0037] FIG. 5 is a diagram showing O1s XPS results of the product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source and CuCl as molten salt, wherein a mass ratio between TiH.sub.2 and CuCl is 1:4.

[0038] FIG. 6 is an XRD pattern showing the product obtained by reacting 4 h at 500° C. using TiO as a Ti source and CuCl as molten salt, wherein a mass ratio between TiO and CuCl is 1:6.

[0039] FIG. 7 is a TEM image showing the product obtained by reacting 4 h at 500° C. using TiO as a Ti source and CuCl as molten salt, wherein a mass ratio of TiO and CuCl is 1:6.

[0040] FIG. 8 is an XRD pattern showing the product obtained by reacting 6 h at 550° C. using TiCN as a Ti source and ZnBr.sub.2 as molten salt, wherein a mass ratio of TiCN and ZnBr.sub.2 is 1:6.

[0041] FIG. 9 is an XRD pattern showing the product obtained by reacting 6 h at 550° C. using TiCN as a Ti source and ZnBr.sub.2 as molten salt, wherein a mass ratio of TiCN and ZnBr.sub.2 is 1:6.

[0042] FIG. 10 is an XRD pattern showing the product obtained by reacting 6 h at 700° C. using Ti.sub.2O.sub.3 as a Ti source and CoBr.sub.2 as molten salt, wherein a mass ratio between Ti.sub.2O.sub.3 and CoBr.sub.2 is 1:5.

[0043] FIG. 11 is a TEM image showing the product obtained by reacting 6 h at 700° C. using Ti.sub.2O.sub.3 as a Ti source and CoBr.sub.2 as molten salt, wherein a mass ratio of Ti.sub.2O.sub.3 and CoBr.sub.2 is 1:5.

[0044] FIG. 12 is a diagram showing comparison between photo catalyzing and degrading rhodamine B with the product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source and CuCl as molten salt with a mass ratio between TiH.sub.2 and CuCl 1:4 and with pure TiO.sub.2.

[0045] FIG. 13 is a diagram showing comparison between rhodamine B photo catalysis and degradation results by respectively the product obtained by reacting 6 h at 550° C. using TiCN as a Ti source and ZnBr.sub.2 as molten salt with a mass ratio between TiCN and ZnBr.sub.2 1:6 and with pure TiO.sub.2.

EMBODIMENTS

[0046] To make the purposes, features and advantages of the present invention more obvious, hereinafter a detailed description will be given to embodiments of the present invention in conjunction with accompanying drawings. In the following description, many specific details are set forth for full understanding of the present invention. However, the present invention can be realized in many other ways different from those described here, those of ordinary skill in the art can make modifications without departing from principles of the present invention, thus the present invention is not limited by the following specific embodiments. Targeting at problems existing in the prior art, the present invention provides a preparation method for reduced titanium dioxide photo catalyst by transition metal halide molten salt, hereinafter the present invention will be described in detail in conjunction with the accompanying drawings.

[0047] As shown in FIG. 1, a preparation method of reduced titanium dioxide photo catalyst by transition metal halide molten salt provided in the present invention, comprises the following steps:

[0048] S101: weighing TiO and CuCl respectively, mixing fully and grinding in a mortar, transferring the same to a melting pot, putting into a muffle furnace, heating at a certain heating rate to 430˜600° C.;

[0049] S102: maintaining the temperature for a certain period of time, shutting down power supply, furnace cooling until ambient temperature, taking out the melting pot, adding hot water for full ultrasonic or mixing treatment; and

[0050] S103: filtering and washing a product, vacuum drying the same and reduced TiO.sub.2−x is obtained.

[0051] Hereinafter the technical solutions in the present invention will be further described in conjunction with some embodiments.

[0052] Usually among methods for preparing TiO.sub.2 or doped TiO.sub.2 by molten salt, usually TiOSO.sub.4 or Ti(SO.sub.4).sub.2 are used as a Ti source, and alkali metal halide and phosphate such as composites of NaCl, KCl, Na.sub.2HPO.sub.4, and K.sub.2HPO.sub.4, are used as molten salt, pure TiO.sub.2 is obtained, or pure TiO.sub.2 is used as a Ti source, add other complexes in the molten salt to obtain doped TiO.sub.2. With the former method only pure TiO.sub.2 can be obtained, and the Ti source is liable to hydrolyze and during mixing and grinding influence of water shall be avoided. With the latter method, usually two-step reaction is required, that is, first of all prepare and obtain TiO.sub.2 and then conduct doping reaction in molten salt.

[0053] In the present invention, low-valence complexes such as TiH.sub.2, TiO, Ti.sub.2O.sub.3, and TiCN are used as a Ti source, any one or combination of transition metal halides such as CuCl (with a fusion point 426° C.), CuBr (492° C.), ZnBr.sub.2 (394° C.), FeCl.sub.3 (308° C.), CoCl.sub.2 (724° C.) and CoBr.sub.2 (678° C.) are used as molten salt, mix the Ti source and the molten salt as per a mole ratio of 1:1 to 1:8 and grind the same, heat at air atmosphere until no less than the fusion point of the molten salt, keep the transition metal halide in a state of melting, maintaining the temperature for 2-8 h, separate by washing with water, and reduced TiO.sub.2−x photo catalyst rich in Ti.sup.3+ and Ov with excellent visible light response capability can be obtained.

[0054] Typical Preparation Processes:

[0055] Weigh TiO 1 g and CuCl 4 g, mixing fully and grind in a mortar for 10-30 minutes, transfer to a melting pot, put the same into a muffle furnace, heat at a heating rate of 2-10° C./min until the temperature is 430-600° C., maintain the temperature or 2-8 h, shut down power supply, furnace cool until ambient temperature, take out the melting pot, put hot water at 40-80° C. for full ultrasonic or mixing treatment (in order to expedite dissolution of CuCl, as CuCl is not soluble in cold water), filter, wash, vacuum dry at ambient temperature for 2-12 h, and reduced TiO.sub.2−x is obtained.

[0056] In the foregoing preparation processes, TiO can be replaced with TiH.sub.2, Ti.sub.2O.sub.3, and TiCN, a mass of CuCl can vary from 2 g to 8 g, TiO can also be replaced with CuBr (492° C.), ZnBr.sub.2 (394° C.), FeCl.sub.3 (308° C.), CoCl.sub.2 (724° C.) and CoBr.sub.2 (678° C.), and the lowest temperature after heating shall be no lower than the fusion point of corresponding molten salts. Time for maintaining the temperature is 2-8 hours, CuCl and CuBr shall be washed with water and the others can be mixed at ambient temperature or treated by ultrasonic washing.

[0057] FIG. 2 is an XRD pattern showing a product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source, CuCl as molten salt, wherein a mass ratio between TiH.sub.2 and CuCl is 1:4.

[0058] FIG. 3 is a TEM image of the product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source and CuCl as molten salt, wherein a mass ratio between TiH.sub.2 and CuCl is 1:4.

[0059] FIG. 4 is a diagram showing Ti 2p XPS results of the product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source and CuCl as molten salt, wherein a mass ratio between TiH.sub.2 and CuCl is 1:4.

[0060] FIG. 5 is a diagram showing O1s XPS results of the product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source and CuCl as molten salt, wherein a mass ratio between TiH.sub.2 and CuCl is 1:4.

[0061] FIG. 6 is an XRD pattern showing the product obtained by reacting 4 h at 500° C. using TiO as a Ti source and CuCl as molten salt, wherein a mass ratio between TiO and CuCl is 1:6.

[0062] FIG. 7 is a TEM image showing the product obtained by reacting 4 h at 500° C. using TiO as a Ti source and CuCl as molten salt, wherein a mass ratio of TiO and CuCl is 1:6.

[0063] FIG. 8 is an XRD pattern showing the product obtained by reacting 6 h at 550° C. using TiCN as a Ti source and ZnBr.sub.2 as molten salt, wherein a mass ratio of TiCN and ZnBr.sub.2 is 1:6.

[0064] FIG. 9 is an XRD pattern showing the product obtained by reacting 6 h at 550° C. using TiCN as a Ti source and ZnBr.sub.2 as molten salt, wherein a mass ratio of TiCN and ZnBr.sub.2 is 1:6.

[0065] FIG. 10 is an XRD pattern showing the product obtained by reacting 6 h at 700° C. using Ti.sub.2O.sub.3 as a Ti source and CoBr.sub.2 as molten salt, wherein a mass ratio between Ti.sub.2O.sub.3 and CoBr.sub.2 is 1:5.

[0066] FIG. 11 is a TEM image showing the product obtained by reacting 6 h at 700° C. using Ti.sub.2O.sub.3 as a Ti source and CoBr.sub.2 as molten salt, wherein a mass ratio of Ti.sub.2O.sub.3 and CoBr.sub.2 is 1:5.

[0067] In the present invention, low-valence titanium complexes stable in air and water are used as Ti sources, transition metal halide given here is used as molten salt, upon one-step fusion reaction, reduced Ti.sub.2−x rich in Ti.sup.3+ and Ov can be obtained. In the present invention, problems that conventional defect titanium dioxide preparation involves multiple steps and inflammable and explosive reducing gases or other dangerous reducing agents or oxidants are used have been addressed; furthermore, the Ti source used is stable in air and water, and the defect that organic solvents and other Ti sources that are liable to hydrolyze has been solved, which is contributive to industrialization thereof. The product obtained in the present invention has excellent visible light response performance, can be used to photo catalyze and degrade organic pollutants in waste water and waste gases, has very good sterilization and disinfection functions and can be used in water treatment and sterilization and disinfection treatment for indoor air.

[0068] FIG. 12 is a diagram showing comparison between photo catalyzing and degrading rhodamine B with the product obtained by reacting 4 h at 450° C. using TiH.sub.2 as a Ti source and CuCl as molten salt with a mass ratio between TiH.sub.2 and CuCl 1:4 and with pure TiO.sub.2.

[0069] FIG. 13 is a diagram showing comparison between rhodamine B photo catalysis and degradation results by respectively the product obtained by reacting 6 h at 550° C. using TiCN as a Ti source and ZnBr.sub.2 as molten salt with a mass ratio between TiCN and ZnBr.sub.2 1:6 and with pure TiO.sub.2.

[0070] The foregoing are only some specific embodiments of the present invention, and the protection scope of the present invention is not limited to these disclosed here, any modification, equivalent replacement and improvement made by one skilled in the art in the technical range disclosed in the present invention within the spirit and principles of the present invention shall be covered in the protection scope of the present invention.