CN104549406A - Composite visible light catalyst of g-C3N4/bismuth-based oxide and preparation method and application of composite visible light catalyst - Google Patents

Abstract

The invention discloses a composite visible light catalyst of a g-C3N4/bismuth-based oxide and a preparation method and an application of the composite visible light catalyst. Carbon nitride in the composite light catalyst is graphite-phase carbon nitride; and the bismuth-based oxide is more than one of Bi2O2CO3, BiOBr, BiOCl, Bi2WO6, BiVO4 and BiOI. The components of the obtained composite catalyst are tight in contact, so that separation of photo electron-hole pairs is facilitated, and the photocatalytic efficiency is also improved; the composite catalyst has good degradation efficiency on organic pollutants represented by methyl orange under sunlight illumination; the preparation method disclosed by the invention has the characteristics of being simple in process, simple and convenient to operate, and cheap in raw materials; the prepared composite catalyst can be widely applied to waste water treatment, atmospheric purification and the like; and a new concept is provided for design of the novel composite visible light catalyst by the preparation method.

Description

A kind of g-C 3n 4/ bismuth system oxide composite visible light catalyst and preparation method thereof and application

Technical field

The invention belongs to technical field of function materials, be specifically related to a kind of g-C ₃n ₄/ bismuth system oxide composite visible light catalyst and preparation method thereof and application.

Background technology

The very promising environment remediation technology of one with the organic or inorganic pollutent in Photocatalitic Technique of Semiconductor processing environment.The success of this technology depends primarily on the development with visible light-responded semiconductor light-catalyst.At present, the non-metal semiconductive g-C of graphite-phase ₃n ₄the visible light-responded performance superior due to it and cause the extensive concern of people.G-C ₃n ₄energy gap be about 2.7 eV, obtained by the reaction of simple thermal polycondensation primarily of some precursors cheap and easy to get (as urea, trimeric cyanamide etc.).But pure g-C ₃n ₄lower photocatalytic activity is shown because its quantum yield is not high.The composite semiconductor building heterojunction structure effectively can suppress the compound of photo-generated carrier, thus improves the photocatalytic activity of semi-conductor, is a kind of efficient semiconductor Photocatalyst method.In recent years, g-C ₃n ₄/ TiO ₂, g-C ₃n ₄/ Co ₃o ₄composite semiconductor Deng heterojunction structure occurs in succession, effectively improves the visible light catalysis activity of semi-conductor.

Bismuth system oxide is widely studied application due to the laminate structure of its uniqueness, controlled microscopic appearance and good ultraviolet or visible light catalysis activity.Bi ₂o ₃as unit oxide compound the most basic in bismuth system oxide, it can derive various different bismuth system oxide, as Bi ₂o ₂cO ₃, BiOBr, BiOCl, Bi ₂wO ₆, BiVO ₄deng.The present invention is mainly with Bi ₂o ₃for bismuth source builds g-C ₃n ₄with the heterojunction structure of bismuth system oxide, be intended to improve the not high shortcoming of single catalyst photocatalytic activity.At present, the method building heterojunction structure, mainly by wherein a kind of monomer prepared being added in the precursor of another kind of monomer, forms matrix material subsequently.And the present invention is by directly mixing the precursor of two kinds of monomers, namely generates matrix material by brief heat treating, and only need change g-C ₃n ₄precursor can prepare different matrix materials, this for preparation g-C ₃n ₄the preparation of based composites provides new thinking.

Summary of the invention

The object of the present invention is to provide a kind of g-C ₃n ₄/ bismuth system oxide composite visible light catalyst and preparation method thereof and application.The present invention adopts original position technology of preparing, by dinectly bruning Bi ₂o ₃with different g-C ₃n ₄precursor power g-C ₃n ₄/ bismuth system oxide composite visible light catalyst.Obtained composite photo-catalyst has good visible light photocatalysis active, and stablizes resistance to photoetch.

The object of the invention is achieved through the following technical solutions:

A kind of g-C ₃n ₄/ bismuth system oxide composite visible light catalyst, described composite photo-catalyst is mainly by g-C ₃n ₄with the binary optical catalyzer of bismuth system oxide composition, because this special original position preparation means makes bismuth system oxide from g-C ₃n ₄body mutually in grow out, the contact thus in composite catalyst between two kinds of materials is more tight, g-C in composite catalyst ₃n ₄mass ratio be 40 wt%-80 wt%.

A kind of g-C ₃n ₄the preparation method of/bismuth system oxide composite visible light catalyst, comprises the following steps:

(1) Bi is prepared ₂o ₃powder: by 10 ~ 13 g Bi (NO ₃) ₃5H ₂o is dissolved in 30 ~ 40 ml HNO ₃in the aqueous solution, stirred at ambient temperature dissolves, dropwise add NaOH solution subsequently until pH=11 ~ 13 of solution, yellow suspension is moved in 80 ~ 100 DEG C of water-baths after stirring 1.5 ~ 2.5 h extremely neutral with deionized water wash, yellow mercury oxide is placed on 300 ~ 400 DEG C of calcining 2 ~ 4 h in retort furnace in 80 ~ 100 DEG C of oven dry and namely obtains Bi ₂o ₃powder; Described HNO ₃the concentration of the aqueous solution is 1 ~ 1.5 mol/L; The concentration of described NaOH solution is 10 ~ 12 mol/L;

(2) g-C ₃n ₄the preparation of/bismuth system oxide composite photo-catalyst: by the Bi described in step (1) ₂o ₃powder and g-C ₃n ₄precursor mixes, and is moved in semi-enclosed alumina crucible by mixture subsequently, is placed in the calcining of retort furnace blowing air and obtains g-C ₃n ₄/ bismuth system oxide composite photo-catalyst.

In aforesaid method, the temperature of step (1) described stirring is 25 ~ 35 DEG C, and stir speed (S.S.) is 15 ~ 25 r/min.

In aforesaid method, step (2) described g-C ₃n ₄precursor is more than one in trimeric cyanamide, Guanidinium hydrochloride, urea, thiocarbamide, Dicyanodiamide.

In aforesaid method, the calcining temperature described in step (2) is 500 ~ 650 DEG C, and calcination time is 2 ~ 3 h, and temperature rise rate is 3 ~ 10 DEG C/min.

In aforesaid method, step (2) described g-C ₃n ₄g-C in/bismuth system oxide composite photo-catalyst ₃n ₄mass ratio be 40 wt%-80 wt%.

A kind of g-C ₃n ₄/ bismuth system oxide composite visible light catalyst, the carbonitride in catalyzer is graphite phase carbon nitride, and bismuth system oxide is Bi ₂o ₂cO ₃, BiOBr, BiOCl, Bi ₂wO ₆, BiVO ₄, more than one in BiOI.

A kind of g-C ₃n ₄/ bismuth system oxide composite visible light catalyst can be widely used in waste water treatment.Waste water in described waste water treatment is methyl orange dye waste water.

The present invention and g-C of the prior art ₃n ₄preparation method (the g-C prepared of base composite photocatalyst ₃n ₄other semi-conductor of upper attachment) existence difference in essence, the present invention adopts Bi ₂o ₃with different g-C ₃n ₄precursor mixing heat-treating methods, utilize Bi ₂o ₃the feature of different bismuth system oxide can be transformed in certain circumstances, prepare different g-C ₃n ₄/ bismuth system oxide composite photo-catalyst.Contact in the composite photo-catalyst that this original position obtains between component is very tight, thus is more conducive to the charge transfer between interface, inhibits the compound of photo-generated carrier, improves photocatalytic activity.

Compared with prior art, the present invention has following advantage:

Preparation method of the present invention has that technique is simple, easy and simple to handle, the feature of cheaper starting materials, only by directly being mixed by the precursor of monomer in two, namely need generate matrix material, and only need change g-C by brief heat treating ₃n ₄precursor can prepare different matrix materials.Prepared composite catalyst (1mw/cm under visible light ²) showing good photocatalytic activity, this catalyzer can be widely used in the aspect such as waste water treatment, atmospheric cleaning.

Accompanying drawing explanation

Fig. 1 is the pure g-C of the present invention ₃n ₄, pure Bi ₂o ₃, pure Bi ₂o ₂cO ₃, g-C ₃n ₄/ Bi ₂o ₂cO ₃the XRD figure of composite photo-catalyst;

Fig. 2 is the pure g-C of the present invention ₃n ₄, pure Bi ₂o ₃, pure BiOCl, g-C ₃n ₄the XRD figure of/BiOCl composite photo-catalyst;

Fig. 3 a is pure g-C ₃n ₄the field emission scanning electron microscope figure FE-SEM of composite photo-catalyst;

Fig. 3 b is g-C ₃n ₄/ Bi ₂o ₂cO ₃the field emission scanning electron microscope figure FE-SEM of composite photo-catalyst;

Fig. 4 is the pure g-C of the present invention ₃n ₄, pure Bi ₂o ₃, pure Bi ₂o ₂cO ₃, g-C ₃n ₄/ Bi ₂o ₂cO ₃composite photo-catalyst is to the visible light catalytic design sketch of tropeolin-D;

Fig. 5 is the pure g-C of the present invention ₃n ₄, pure Bi ₂o ₃, pure BiOCl, g-C ₃n ₄/ BiOCl composite photo-catalyst is to the visible light catalytic design sketch of tropeolin-D.

Embodiment

Do specifically to describe in detail further to the present invention below in conjunction with specific embodiment, but embodiments of the present invention are not limited thereto, for the processing parameter do not indicated especially, can refer to routine techniques and carry out.

embodiment 1

Bi ₂o ₃the preparation of powder: by 10 g Bi (NO ₃) ₃5H ₂o is dissolved in 30 ml HNO ₃in the aqueous solution (1 mol/L), stirred at ambient temperature dissolves, dropwise add NaOH solution (10 mol/L) subsequently until the pH=11 of solution, yellow suspension is moved in 80 DEG C of water-baths after stirring 1.5 h extremely neutral with deionized water wash, yellow mercury oxide is placed on 300 DEG C of calcining 3 h in retort furnace in 80 DEG C of oven dry and namely obtains Bi ₂o ₃powder.

embodiment 2

G-C ₃n ₄the preparation of photocatalyst.Take 5 g trimeric cyanamides and be placed in semi-enclosed alumina crucible, at 550 DEG C, calcine 3 h after moving into retort furnace, temperature rise rate is 3 DEG C/min, grinds and obtain g-C after naturally cooling to room temperature ₃n ₄powder.

embodiment 3

G-C ₃n ₄/ Bi ₂o ₂cO ₃the preparation of composite photo-catalyst.Take the Bi of gained in 5.0 g trimeric cyanamides and 1.3 g embodiments 1 ₂o ₃powder, mixing is placed in semi-enclosed alumina crucible, and at 550 DEG C, calcine 2 h after moving into retort furnace, temperature rise rate is 3 DEG C/min, grinds and obtain g-C after being cooled to room temperature ₃n ₄/ Bi ₂o ₂cO ₃composite photo-catalyst, wherein g-C ₃n ₄mass ratio in composite catalyst is 60 wt%.The XRD figure (Fig. 1) of different photocatalyst shows Bi ₂o ₃successful transformation is Bi ₂o ₂cO ₃.In addition, Bi can be found out from scanning electron microscope (SEM) photograph (Fig. 3 a and Fig. 3 b) ₂o ₂cO ₃from g-C ₃n ₄body mutually in grow out, both close contacts.

embodiment 4

G-C ₃n ₄the preparation of/BiOCl composite photo-catalyst.Take the Bi of gained in 5.0 g Guanidinium hydrochlorides and 0.7 g embodiment 1 ₂o ₃powder, mixing is placed in semi-enclosed alumina crucible, and at 500 DEG C, calcine 3 h after moving into retort furnace, temperature rise rate is 5 DEG C/min, grinds and obtain g-C after being cooled to room temperature ₃n ₄/ BiOCl composite photo-catalyst, wherein g-C ₃n ₄mass ratio in composite catalyst is 75 wt%.The XRD figure (Fig. 2) of different photocatalyst shows Bi ₂o ₃successful transformation is BiOCl.

embodiment 5

Bi ₂o ₃the preparation of powder: by 13 g Bi (NO ₃) ₃5H ₂o is dissolved in 40 ml HNO ₃in the aqueous solution (1.3 mol/L), stirred at ambient temperature dissolves, dropwise add NaOH solution (12 mol/L) subsequently until the pH=12 of solution, yellow suspension is moved in 100 DEG C of water-baths after stirring 2 h extremely neutral with deionized water wash, yellow mercury oxide is placed on 400 DEG C of calcining 3 h in retort furnace in 90 DEG C of oven dry and namely obtains Bi ₂o ₃powder.

G-C ₃n ₄/ Bi ₂o ₂cO ₃the preparation of composite photo-catalyst.Take 3.0 g trimeric cyanamides and 1.3 g Bi ₂o ₃powder, mixing is placed in semi-enclosed alumina crucible, and at 600 DEG C, calcine 2.5 h after moving into retort furnace, temperature rise rate is 6 DEG C/min, grinds and obtain g-C after being cooled to room temperature ₃n ₄/ Bi ₂o ₂cO ₃composite photo-catalyst, wherein g-C ₃n ₄mass ratio in composite catalyst is 40 wt%.Product effect in the present embodiment can refer to Fig. 3 b.

embodiment 6

Bi ₂o ₃the preparation of powder: by 12 g Bi (NO ₃) ₃5H ₂o is dissolved in 35 ml HNO ₃in the aqueous solution (1.5 mol/L), stirred at ambient temperature dissolves, dropwise add NaOH solution (11 mol/L) subsequently until the pH=13 of solution, yellow suspension is moved in 90 DEG C of water-baths after stirring 2.5 h extremely neutral with deionized water wash, yellow mercury oxide is placed on 350 DEG C of calcining 4 h in retort furnace in 100 DEG C of oven dry and namely obtains Bi ₂o ₃powder.

G-C ₃n ₄/ Bi ₂o ₂cO ₃the preparation of composite photo-catalyst.Take 15 g trimeric cyanamides and 1.3 g Bi ₂o ₃powder, mixing is placed in semi-enclosed alumina crucible, and at 650 DEG C, calcine 2 h after moving into retort furnace, temperature rise rate is 10 DEG C/min, grinds and obtain g-C after being cooled to room temperature ₃n ₄/ Bi ₂o ₂cO ₃composite photo-catalyst, wherein g-C ₃n ₄mass ratio in composite catalyst is 80 wt%.Product effect in the present embodiment can refer to Fig. 3 b.

embodiment 7

Photocatalytic activity is analyzed: employing tropeolin-D is model pollutant, compares the photocatalytic activity of different photocatalyst.Photocatalytic degradation reaction is carried out in homemade photocatalytic reaction device, and catalyzer (product of embodiment 3) dosage is 100 mg, and light source is 500 W halogen tungsten lamps; Light intensity is 1 mw/cm ²; The starting point concentration of tropeolin-D is 20 mg/L; Halfhour dark absorption reaction is first carried out before opening halogen tungsten lamp; By measuring solution at the absorbance at 464 nm wavelength places and the clearance of combined standard curve calculation tropeolin-D: D=(C ₀-C)/C ₀× 100%, C ₀for the starting point concentration of tropeolin-D, C is the concentration of t tropeolin-D.Experimental result shows, g-C ₃n ₄/ Bi ₂o ₂cO ₃and g-C ₃n ₄/ BiOCl composite photo-catalyst all shows than single g-C ₃n ₄, Bi ₂o ₂cO ₃, BiOCl and Bi ₂o ₃higher photocatalytic activity, removes the tropeolin-D (Figure 4 and 5) of about 70%, shows good photocatalytic activity in 300 min.(embodiment 3 corresponding diagram 4, embodiment 4 corresponding diagram 5)

Above embodiment is only the condition restriction that technical scheme of the present invention and non-critical are described, the ordinary person of this area should be appreciated that and can make a variety of changes it its details or form not departing from the spirit and scope of the present invention that claims limit.

Claims (8)

1. a g-C ₃n ₄the preparation method of/bismuth system oxide composite visible light catalyst, is characterized in that, comprises the following steps:

(1) Bi is prepared ₂o ₃powder: by 10 ~ 13 g Bi (NO ₃) ₃5H ₂o is dissolved in 30 ~ 40 ml HNO ₃in the aqueous solution, stirred at ambient temperature dissolves, dropwise add NaOH solution subsequently until pH=11 ~ 13 of solution, yellow suspension is moved in 80 ~ 100 DEG C of water-baths after stirring 1.5 ~ 2.5 h extremely neutral with deionized water wash, yellow mercury oxide is placed on 300 ~ 400 DEG C of calcining 2 ~ 4 h in retort furnace in 80 ~ 100 DEG C of oven dry and namely obtains Bi ₂o ₃powder; Described HNO ₃the concentration of the aqueous solution is 1 ~ 1.5 mol/L; The concentration of described NaOH solution is 10 ~ 12 mol/L;

(2) g-C ₃n ₄the preparation of/bismuth system oxide composite photo-catalyst: by the Bi described in step (1) ₂o ₃powder and g-C ₃n ₄precursor mixes, and is moved in semi-enclosed alumina crucible by mixture subsequently, is placed in the calcining of retort furnace blowing air and obtains g-C ₃n ₄/ bismuth system oxide composite photo-catalyst.

2. g-C according to claim 1 ₃n ₄the preparation method of/bismuth system oxide composite visible light catalyst, is characterized in that, the temperature of step (1) described stirring is 25 ~ 35 DEG C, and stir speed (S.S.) is 15 ~ 25 r/min.

3. g-C according to claim 1 ₃n ₄the preparation method of/bismuth system oxide composite visible light catalyst, is characterized in that, step (2) described g-C ₃n ₄precursor is more than one in trimeric cyanamide, Guanidinium hydrochloride, urea, thiocarbamide, Dicyanodiamide.

4. g-C according to claim 1 ₃n ₄the preparation method of/bismuth system oxide composite visible light catalyst, is characterized in that, the calcining temperature described in step (2) is 500 ~ 650 DEG C, and calcination time is 2 ~ 3 h, and temperature rise rate is 3 ~ 10 DEG C/min.

5. g-C according to claim 1 ₃n ₄the preparation method of/bismuth system oxide composite visible light catalyst, is characterized in that, step (2) described g-C ₃n ₄g-C in/bismuth system oxide composite photo-catalyst ₃n ₄mass ratio be 40 wt%-80 wt%.

6. prepare g-C by preparation method described in claim 1-6 ₃n ₄/ bismuth system oxide composite visible light catalyst, is characterized in that, the carbonitride in catalyzer is graphite phase carbon nitride, and bismuth system oxide is Bi ₂o ₂cO ₃, BiOBr, BiOCl, Bi ₂wO ₆, BiVO ₄, more than one in BiOI.

7. g-C described in claim 6 ₃n ₄/ bismuth system oxide composite visible light catalyst is applied to waste water treatment.

8. application according to claim 7, is characterized in that, the waste water in described waste water treatment is methyl orange dye waste water.