CN104588065B

CN104588065B - Rare-earth composite g-C3N4 graphene photocatalyst and preparation method thereof

Info

Publication number: CN104588065B
Application number: CN201510063091.8A
Authority: CN
Inventors: 付明来; 黄民忠; 曾婉艺; 崔浩杰
Original assignee: Institute of Urban Environment of CAS
Current assignee: Institute of Urban Environment of CAS
Priority date: 2015-02-09
Filing date: 2015-02-09
Publication date: 2017-02-22
Anticipated expiration: 2035-02-09
Also published as: CN104588065A

Abstract

The invention relates to a photocatalytic material for treating organic pollutants in water and a preparation method thereof. The photocatalytic material is formed by compounding layered semiconductor g-C3N4 graphene material with visible-light response and beta-NaYF4: Yb＜3+＞, Tm＜3+＞ rare-earth nanoparticles with upconversion performance, wherein the beta-NaYF4: Yb＜3+＞, Tm＜3+＞ rare-earth nanoparticles are uniformly distributed on the surface of the g-C3N4 graphene material, and a composite photocatalytic material with heterostructure and near-infrared light response is formed. According to successful compounding of the rare-earth nanoparticles, the g-C3N4 graphene can absorb visible light emitted by the rare earth through upconversion, so that the infrared light response is realized. The catalyst has excellent catalytic activity under near-infrared light, the concentration of the organic pollutants in the water can be rapidly reduced in a short time, and finally the pollutants can be almost completely degraded. The preparation method is simple and feasible, and the catalyst can be conveniently recycled and has wide application prospects.

Description

A kind of rare earth is combined g-C3N4Class graphene photo-catalyst and preparation method thereof

Technical field

The invention belongs to a kind of catalysis material and preparation method thereof, specifically a kind of rare earth is combined g-C₃N₄Class stone Black alkene photochemical catalyst and preparation method thereof, this catalyst can be activated by near infrared light, the organic pollution in catalytic degradation water.

Background technology

Since Fujishima in 1972 finds that titanium dioxide can be with decomposition water under action of ultraviolet light, semiconductor light Catalysis technique is progressively emerging to grow up.Semiconductor light-catalyst, can not only used as a kind of environmentally friendly catalysis new technology Oxidative degradation organic pollution, makes the material permineralization of a lot of bio-refractories, and itself is nontoxic, stable performance, does not produce Raw secondary pollution, low cost, less energy consumption, reaction condition is gentle, operation is simple, recyclable the advantages of recycle, it has also become generation The focus of boundary scholars research.

Most of semiconductor light-catalysts can only respond ultraviolet light or visible ray, is such as widely used in photocatalysis neck at present The titanium dioxide in domain can only respond ultraviolet light, metal-free g-C₃N₄Class graphene semiconductor also can only responding to visible light.Although Chinese scholars have carried out substantial amounts of study on the modification to semiconductor light-catalyst, but photoresponse are extended to the example of infrared light region Son is very limited, and its utilization ratio has much room for improvement.Near infrared light about 44% in solar energy, this part infrared light does not have It is utilized effectively, greatly reduces the utilization rate to solar energy for the photochemical catalyst, thus affecting its photocatalysis efficiency.

Rare earth up-conversion luminescent material as a kind of material that lower energy photon can be converted to high-energy photon, we by its With g-C₃N₄Class Graphene is combined by certain combination, using the characteristic of up-conversion luminescent material, absorbs near infrared Light, sends the visible ray of short wavelength so that semiconductor indirect utilization near infrared light by up conversion, improves to solar energy Comprehensive utilization ratio.

Content of the invention

It is an object of the invention to provide a kind of rare earth is combined g-C₃N₄Class Graphene catalysis material and preparation method thereof, Prepared composite photo-catalyst can respond near infrared light, improves the profit near infrared light region in Photocatalitic Technique of Semiconductor field With efficiency, thus improving it to solar energy utilization rate, and it is applied to field of environmental improvement.

The present invention adopts the technical scheme that：

A kind of rare earth is combined g-C₃N₄Class graphene photo-catalyst is it is characterised in that this photochemical catalyst is β-NaYF₄:Yb³⁺, Tm³⁺Nano particle and g-C₃N₄Class grapheme material is combined composition, β-NaYF₄:Yb³⁺,Tm³⁺Nano particle is evenly distributed in The heterojunction structure being formed on stratiform class graphene nanometer sheet, preparation method step is：

（1）Weigh 0.1 g Y₂O₃In three-necked bottle, it is charged with 10 ml trifluoroacetic acids and 10 ml deionized waters, then Three-necked bottle is placed in 75 DEG C of oil bath pan, is heated to reflux 6 h under magnetic stirring, until muddy white solution bleach is clear Till clear, finally take out and put into 80 DEG C of oven for drying just available (CF a whole night₃COO)₃Y powdered product.In addition, with same Method is prepared for (CF₃COO)₃Yb and (CF₃COO)₃Tm powder；

（2）Weigh 1 mmol step（1）The trifluoroacetate preparing（Y³⁺：Yb³⁺：Tm³⁺Mol ratio be 0.78:0.2: 0.02）In 100 ml three-necked bottles, adding 2 mmol sodium trifluoroacetates in wherein, then sequentially adding mol ratio is 8：10：5 Oleic acid, 1- octadecylene and oleyl amine.Under nitrogen protective atmosphere encloses, by the above-mentioned three-necked bottle having been added in various reaction reagents in In 110 DEG C of oil bath pan, magnetic agitation heats 30 min, until mixed solution becomes clarification, obtains solution A；

（3）Under nitrogen protective atmosphere encloses, by solution A at 330 DEG C continuous heating 1 h, question response is cooled to room after terminating Temperature, deionized water and absolute ethyl alcohol centrifuge washing are dried several times afterwards, just can get up-conversion luminescence nano particle β-NaYF₄: Yb³⁺,Tm³⁺.

（4）Weigh melamine powder add have in the semi-enclosed porcelain crucible of lid, then with firing rate for 10 DEG C/ The speed of min is heated to 500 DEG C and continues 2 h.Then further gone ammonia treatment again, that is, be heated to 520 DEG C, and hold Continuous 2 h.Finally cool down room temperature, the material after grinding is calcined just can get the g-C of yellow₃N₄Powder.

（5）Weigh step（4）The g-C having prepared₃N₄Semiconductor powder add equipped with methanol solution beaker in, Then beaker is put into after ultrasonic 30min in ultrasonic device, then add step inside（3）The β NaYF having prepared₄:Yb³⁺, Tm³⁺, then beaker is placed magnetic agitation 24h in ventilating kitchen, till the methanol solution in beaker all evaporates and does, finally will Obtained product is calcined 1h at 250 DEG C and is just obtained near-infrared composite photo-catalyst.Up-conversion luminescence nano particle β- NaYF₄:Yb³⁺,Tm³⁺Mass ratio near infrared light composite photo-catalyst is adjustable for 5% ~ 50%.

The photoresponse scope of semiconductor light-catalyst can be extended near infrared light, up-conversion luminescence by the present invention indirectly Nano particle β NaYF₄:Yb³⁺,Tm³⁺The near infrared light of absorption can be converted into visible ray, and then vitalizing semiconductor g-C₃N₄And There is photocatalysis.This is used for semiconductor light-catalyst field near infrared light provides a kind of new Technology Ways, for Solve increasingly serious problem of environmental pollution significant.

Brief description

Fig. 1 is the rare-earth beta-NaYF obtaining by embodiment 1₄:Yb³⁺,Tm³⁺Nano particle figure（Transmission electron microscope photo）；

Fig. 2 is the near-infrared composite photo-catalyst β-NaYF obtaining by embodiment 3₄:Yb³⁺,Tm³⁺/g-C₃N₄（Transmission electron microscope Photo）；

Fig. 3 is the β-NaYF as prepared by embodiment 3₄:Yb³⁺,Tm³⁺Quality is 15% near-infrared composite photo-catalyst The photocatalytic degradation curve map to organic dyestuff methylene blue under 980nm near-infrared laser irradiates.

Specific embodiment

It is further elucidated with present disclosure below in conjunction with specific embodiment, but these embodiments are not intended to limit the present invention Protection domain.

Embodiment（One）

Up-conversion luminescence nano particle β-NaYF₄:Yb³⁺,Tm³⁺Preparation process as follows：

（1）Weigh 0.1 g Y₂O₃In three-necked bottle, it is charged with 10 ml deionized waters and 10 ml CF₃COOH is molten Liquid, then three-necked bottle is placed in 75 DEG C of oil bath pan, it is heated to reflux 6 h under magnetic stirring, until muddy white solution becomes Till transparent clarification, finally take out and put into 80 DEG C of oven for drying just available (CF a whole night₃COO)₃Y powdered product.In addition, with Same method is prepared for (CF₃COO)₃Yb and (CF₃COO)₃Tm powder.

（2）Weigh step（1）The trifluoroacetate 0.78 mmol (CF preparing₃COO)₃Y、0.2 mmol (CF₃COO)₃Yb and 0.02 mmol (CF₃COO)₃Tm, in 100 ml three-necked bottles, adds 2 mmol sodium trifluoroacetates in it In, then sequentially add 10 mmol 1- octadecylenes, 8 mmol oleic acid and 5 mmol oleyl amines.

Under nitrogen protective atmosphere encloses, by the above-mentioned three-necked bottle having been added in various reaction reagents in 110 DEG C of oil bath pan Middle magnetic agitation heats 30 min, until mixed solution becomes clarification, obtains solution A.Purpose is exactly for removing water and oxygen in solution Gas, lays the groundwork for follow-up reaction.

（3）Again solution A is heated to 330 DEG C, equally encloses lower continuous heating 1 h in nitrogen protective atmosphere, until reaction terminates, It is cooled to room temperature.Finally use ultra-pure water and absolute ethyl alcohol 1：1 mixed solution is washed through desk centrifuge 104 rpm/10 min centrifugation Wash 3 ~ 5 times.After thing to be precipitated is cleaned, put into 80 DEG C of dried overnight changes in vacuum drying chamber and can obtain with up-conversion luminescence property β-NaYF₄:Yb³⁺,Tm³⁺Nano particle（Fig. 1）.

Embodiment（Two）

Semi-conducting material g-C₃N₄Preparation process as follows：

Weigh 5g melamine powder add have in the semi-enclosed porcelain crucible of lid, then with firing rate for 10 DEG C/ The speed of min is heated to 500 DEG C and continues 2h.Then further gone ammonia treatment again, that is, be heated to 520 DEG C, and continued 2h.Finally cool down room temperature, the material after grinding is calcined just can get the g-C of yellow₃N₄Powder.

Embodiment（Three）

β- NaYF₄:Yb³⁺,Tm³⁺Quality is 15% near-infrared composite photo-catalyst β-NaYF₄:Yb³⁺,Tm³⁺/g-C₃N₄ Preparation process as follows：

Weigh the g-C that 0.283 g embodiment two has prepared₃N₄Semiconductor powder adds molten equipped with the methyl alcohol of 150 mL In the beaker of liquid, then beaker is put into after ultrasonic 30 min in ultrasonic device, then add 0.05 g embodiment one inside β-the NaYF preparing₄:Yb³⁺,Tm³⁺, then beaker is placed magnetic agitation 24h in ventilating kitchen, the methanol solution in beaker All evaporate till doing, then move into calcining 1h at 250 DEG C in Muffle furnace, just can obtain the near-infrared complex light with heterojunction structure Catalyst β-NaYF₄:Yb³⁺,Tm³⁺/g-C₃N₄（Fig. 2）.

Embodiment（Four）

β- NaYF₄:Yb³⁺,Tm³⁺Quality is 15% near-infrared composite photo-catalyst β-NaYF₄:Yb³⁺,Tm³⁺/g-C₃N₄ Under 980nm near-infrared laser irradiates, the specific experiment step of degradating organic dye methylene blue is as follows：

The methylene blue that near-infrared composite photo-catalyst prepared by 1 mg embodiment three is scattered in equipped with 0.5 ml is molten Liquid（Concentration is 15ppm）Quartzy centrifuge tube in, the dispersion liquid mixing is placed in 2 h in the camera bellows of lucifuge and reaches absorption Balance；Then in camera bellows with launch wavelength be 980 nm near infrared light semiconductor diode laser as light source（Power output For 1W）Irradiate reaction system, according to the time interval of 2h, with 1mL syringe take from quartzy centrifuge tube 0.3mL reactant liquor in In 2mL centrifuge tube, with 12000 rpm rotating speed high speed centrifugation 10 min, take supernatant 0.25mL in micro quartz colorimetric utensil, Its absorbance is surveyed in spectrophotometer（Refunded again after having surveyed to quartzy centrifuge tube and continued illumination）, thus when obtaining each Between the photocatalytic degradation effect figure to methylene blue for the near-infrared composite photo-catalyst under section.

Fig. 3 is prepared β-NaYF₄:Yb³⁺,Tm³⁺Quality be 15% near-infrared composite photo-catalyst near in 980nm Photocatalytic degradation curve map to organic dyestuff methylene blue under infrared laser irradiation.It can be seen that it is closely red in 980nm After outer laser shines 6h, β-NaYF₄:Yb³⁺,Tm³⁺Quality be 15% near-infrared composite photo-catalyst to organic dyestuff methylene blue Clearance can reach 82.7%, and as the β-NaYF prepared by the embodiment one of reference under similarity condition₄:Yb³⁺,Tm³⁺With G-C prepared by embodiment two₃N₄Removal to organic dyestuff methylene blue has little to no effect.

Claims

1. a kind of rare earth is combined g-C₃N₄Class graphene photo-catalyst it is characterised in that：This photochemical catalyst is β-NaYF₄:Yb³⁺, Tm³⁺Nano particle and g-C₃N₄Class grapheme material is combined composition, β-NaYF₄:Yb³⁺,Tm³⁺Nano particle is evenly distributed in g- C₃N₄The heterojunction structure being formed on stratiform class graphene nanometer sheet.

2. a kind of rare earth is combined g-C as claimed in claim 1₃N₄Class graphene photo-catalyst, is further characterized in that, β- NaYF₄:Yb³⁺,Tm³⁺Nano particle has hexagonal phase structure；Diameter is spherical in 10-100nm；g-C₃N₄Class Graphene is stratiform The composite that nanometer sheet is formed.

3. a kind of rare earth is combined g-C as claimed in claim 1₃N₄Class graphene photo-catalyst, its preparation method is divided into three steps Suddenly：

(1) three kinds of group of the lanthanides trifluoroacetates and sodium trifluoroacetate are added in three-necked bottle, add a certain proportion of oleic acid, 1- ten Eight alkene and oleyl amine, enclose lower 330 DEG C of pyroreactions 1h in nitrogen protective atmosphere, use after room temperature to be cooled absolute ethyl alcohol and deionized water from The heart washs several times, puts into 80 DEG C of oven for drying and just can get up-conversion luminescence nano particle β-NaYF₄:Yb³⁺,Tm³⁺；

(2) weigh a certain amount of melamine to be placed with the dry pot of lid, more dry pot is put into horse expense stove high temperature calcining, control Heating rate and heat time, just can obtain flaxen semi-conducting material g-C₃N₄；

(3) by prepared g-C in step (2)₃N₄Ultrasonic 30min, obtains g-C in methyl alcohol₃N₄Dispersion liquid；Weigh step again (1) prepared β-NaYF in₄:Yb³⁺,Tm³⁺Be added thereto, under magnetic stirring continuously stirred 24h until methanol solution whole Obtained product is finally calcined 1h at 250 DEG C by evaporation, just can get rare earth and is combined g-C₃N₄Class graphene photo-catalyst.

4. a kind of rare earth is combined g-C as claimed in claim 3₃N₄Class graphene photo-catalyst preparation method, its feature also exists In quality on class graphene nanometer sheet for the rare earth nanometer particle is adjusted in the range of 5%～50%；Its specific surface area is in 10- 32.2m²Between/g.