BISMUTH-TITANIUM OXIDE NANOWIRE MATERIAL USED FOR PHOTOCATALYSIS, AND PREPARATION METHOD

Abstract

The present invention relates to bismuth-titanium oxide composite nanowires used for photocatalysis and a preparation method, belonging to the field of inorganic nanomaterials. The preparation of the bismuth-titanium oxide composite nanowires is: polyvinylpyrrolidone (PVP) and bismuth nitrate are added to N-N dimethylformamide (DMF), tetrabutyl titanate and acetylacetone are added after magnetic stirring has been performed for a period of time, continual stirring is performed for more than six hours, and a transparent, stable solution is obtained. Electrospinning is performed on the solution in an electrospinning generation device under certain conditions, and the obtained electrospinning precursor nano fibres are air-fired in a muffle furnace to remove organic matter. After being cooled to room temperature, the electrospinning precursor nano fibres are placed in a tube furnace to be reduced and sintered in a hydrogen atmosphere. The method is energy-saving and environmentally friendly, the conditions are easy to control, costs are low, and large-scale industrial production is easy. The obtained bismuth-titanium oxide nanowires exhibit good degradation activity on methyl orange under illumination, where the methyl orange degradation rate is reaching more than 95% in a reaction lasting for 20 minutes. The obtained bismuth-titanium oxide nanowires have wide application prospects in relation to sewage treatment.

Claims

1. A bismuth-titanium oxide nanowire material used for photo catalysis, comprising a microstructure of a 200 nm-diameter porous linear structure, wherein a composition of the bismuth-titanium oxide nanowire material comprises a metal bismuth of JCPDS No. 44-1246 and a titanium oxide having a rutile structure of JCPDS No. 21-1272.

2. A method for preparing a bismuth-titanium oxide nanowire material according to claim 1, comprising: (1) adding polyvinylpyrrolidone (PVP) and bismuth nitrate to N-N dimethylformamide (DMF), adding tetrabutyl titanate and acetylacetone after magnetic stirring, continuing the magnetic stirring for more than six hours, and obtaining a transparent and stable sol solution; (2) electrospinning the transparent and stable sol solution obtained in Step (1) in an electrospinning generation device to obtain electrospinning precursor nanofibres; (3) air-firing the electrospinning precursor nanofibres obtained in Step (2) in a muffle furnace at a ramping rate of 5 C./min to remove organic matter; and (4) after cooling to room temperature, reducing and sintering the electrospinning precursor nanofibres obtained in Step (3) in a tube furnace in a hydrogen atmosphere.

3. The method for preparing a bismuth-titanium oxide nanowire material according to claim 2, wherein conditions for a process of electrospinning in Step (2) comprise an ambient temperature of about 20 C. or greater, a humidity of about 85% RH or less, a spinning voltage of about 8 KV to about 25 KV, a needle diameter of about 0.6 mm to about 1.2 mm, and a distance between the needle and a receptor of about 15cm to about 25 cm.

4. The method for preparing a bismuth-titanium oxide nanowire material according to claim 2, wherein during a baking process of air-firing in the muffle furnace in Step (3), a temperature thereof is raised stepwisely, wherein the temperature is raised from a room temperature to 200 C. at a ramping rate of 5 C./min and then raised to 600 C. for 2 hours at a ramping rate of 10 C./min, and finally naturally cooled to the room temperature.

5. The method for preparing a bismuth-titanium oxide nanowire material according to claim 2, wherein during a baking process of reducing and sintering in the tube furnace in Step (4), the baking process of reducing and sintering occurs in a hydrogen atmosphere, and a temperature thereof is raised from a room temperature to 200 C. at a ramping rate of 5 C./min and then raised to 600 C. for 2 hours at a ramping rate of 10 C./min, and finally naturally cooled to the room temperature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0018] FIG. 1 is an XRD pattern of prepared bismuth-titanium oxide nanowires.

[0019] FIG. 2 is an SEM image of prepared bismuth-titanium oxide nanowires.

[0020] FIG. 3 is a TEM image of prepared bismuth-titanium oxide nanowires.

[0021] FIG. 4 shows a photocatalytic effect of prepared bismuth-titanium oxide nanowires on degradation of methyl orange.

DESCRIPTION OF THE EMBODIMENTS

[0022] The present invention will be further described with reference to examples. The production techniques of the present invention are readily practiced by those skilled in the art. The present examples are carried out under the premise of the technical solution of the present invention, and detailed implementations and processes are given; however, the scope of the present invention is not limited to the following examples. The experimental methods in the examples for which no specific conditions are given are generally performed in accordance with conventional conditions or in accordance with the conditions recommended by the manufacturer.

Example 1

[0023] 0.6 g of polyvinylpyrrolidone (PVP) and 4 g of bismuth nitrate were respectively weighed by an electronic balance and added to a beaker where 8 g N-N dimethylformamide (DMF) had already added, and magnetically stirred for 30 minutes. Then, 4 g of tetrabutyl titanate and 0.4 g of acetylacetone were added and stirred continuously for 6 hours so as to obtain a transparent and stable sol solution.

[0024] The sol solution was transferred to and electrospun in an electrospinning generation device. During the electrospinning process, the ambient temperature was controlled to be at 35 C., the humidity was controlled to be about 80% RH, the voltage was controlled to be 15 KV, the needle diameter was controlled to be 0.9 mm, and the reception distance was controlled to be about 15 cm. After the electrospinning process was completed, electrospinning precursor nanofibres were obtained.

[0025] The obtained nanofibres were collected to a crucible by forceps/tweezers and transferred to a muffle furnace. The obtained nano fibres were heated from room temperature to 200 C. at a ramping rate of 5 C./min and then to 600 C. for 2 hours at a ramping rate of 10 C./min and finally naturally cooled to room temperature.

[0026] The sintered nanowires were transferred to a tube furnace, and hydrogen was introduced. The sintered nanowires were heated from room temperature to 200 C. at a ramping rate of 5 C./min and then to 600 C. for 2 hours at a ramping rate of 10 C./min and finally naturally cooled to room temperature.

Photocatalytic Performance Test of the Material

[0027] 0.2 g of bismuth-titanium oxide nanomaterial was accurately weighed, added to 500 ml of a methyl orange (MO) solution (40 mg/L), and then ultrasonically dispersed. The resultant suspension was stirred in the dark for 1 hour to allow the material to reach adsorption equilibrium. After equilibrium was reached, 3 ml of the suspension was removed, and the remaining suspension was poured into a 500 ml quartz tube, and then placed into a photocatalytic reactor. Under illumination with a 500 W high-pressure mercury lamp, for every 5 min, 3 ml of the suspension was removed and transferred to a centrifuge tube, and the total reaction time was 55 min. After the reaction, the samples taken were separated by centrifugation, and the absorbency of the supernatant at about 465 nm was determined by a UV-visible spectrophotometer. Such absorbencies reflected the concentration of the remaining methyl orange after each degradation period, thereby reflecting the degradation effect of the bismuth-titanium oxide photocatalyst prepared through the present method on methyl orange.

[0028] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.