CN108855149A - composite photo-catalyst and preparation method thereof - Google Patents

composite photo-catalyst and preparation method thereof Download PDF

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Publication number
CN108855149A
CN108855149A CN201810602422.4A CN201810602422A CN108855149A CN 108855149 A CN108855149 A CN 108855149A CN 201810602422 A CN201810602422 A CN 201810602422A CN 108855149 A CN108855149 A CN 108855149A
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quantum well
cdse
cdte
cadmium
mos
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梁桂杰
陈美华
汪竞阳
李望南
王松
程晓红
吴凯丰
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Hubei University of Arts and Science
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/30Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/39Photocatalytic properties
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/02Sulfur, selenium or tellurium; Compounds thereof
    • B01J27/057Selenium or tellurium; Compounds thereof
    • B01J27/0576Tellurium; Compounds thereof
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/30Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/396Distribution of the active metal ingredient
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen

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Abstract

Composite photo-catalyst and preparation method thereof belongs to photocatalysis field.Composite photo-catalyst includes MoS2Nanometer sheet and it is adsorbed in MoS2II type CdSe/CdTe Quantum Well of nanometer sheet, II type CdSe/CdTe Quantum Well include CdSe quantum piece stratum nucleare and CdTe quantum piece shell.It has the advantages that extinction is high-efficient, interface charge separative efficiency is high, interface charge compound action is weak, Photocatalyzed Hydrogen Production quantum yield is high.The preparation method of composite photo-catalyst includes that will contain MoS2The ultrasonic disperse in the second reaction solution containing II type CdSe/CdTe Quantum Well is added dropwise in first reaction solution of nanometer sheet, obtains composite photo-catalyst.Its controllability is good, at low cost, applied widely, and photochemical catalyst extinction efficiency obtained and hydrogen generation efficiency are high.

Description

Composite photo-catalyst and preparation method thereof
Technical field
The present invention relates to photocatalysis fields, in particular to a kind of composite photo-catalyst and preparation method thereof.
Background technique
Solar energy photocatalytic produces hydrogen, as " technology of 21 century dream ", it is considered to be finally solve energy and environmental problem One of basic method.From 1972, Fujishima and Honda were reported for the first time using since the phenomenon that Photocatalyzed Hydrogen Production, were ground The persons of studying carefully have carried out a large amount of research around photochemical catalyst and have achieved a series of breakthrough and progress.
Common semiconductor has TiO in photochemical catalyst2、C3N4, NiS etc., and compared with the semiconductor of the quasi-tradition:Quantum The spectrum and energy level of the low-dimensional nanocrystal (such as quantum dot, quantum rod and quantum piece quantum material) of confinement can be with its size tune Section, and the surface due to consumingly expanding to crystal with quantum confined effect its wave function, can significantly enhance nanometer It is brilliant with corresponding charge receptor (such as TiO2With catalyst etc.) the electronics coupled interaction of interface, to be conducive to the two Between interface charge separation;Secondly as strong charge caused by quantum confinement-charge Coulomb interactions, nanocrystalline quantum Material can generate two or more excitons (electron-hole pair) simultaneously by absorbing the photon of a high-energy, this Sample can correspond to 200% even higher " photon-electron " transfer efficiency.This phenomenon becomes low-dimensional quantum material devices It is hopeful to break through the third generation photovoltaic device of the thermodynamics Shockley-Queisser limit, therefore quantum material is in photocatalysis Application prospect it is huge.
However, the prior art has the following problems:First is that the photoabsorption cross-section of zero-dimensional quantum dots or One-dimensional Quantum stick has Limit, the extinction efficiency of catalyst are to be improved;Second is that quantum dot/bar material the electronic structure used is set without special before Meter, electron population is irregular, this is resulted in:One side electronics is transferred to the limited speed in co-catalyst from quantum dot/stick, difficult To realize efficiently separating for the two interface charge;On the other hand, the recombination process for separating the sub- point/stick of state electron vectors is unable to get The service life of effectively control, separation state electronics is influenced by recombination process, it is difficult to meet electronics in co-catalyst long-distance diffusion Demand.The extinction section and quantum dot/stick of above-mentioned zero-dimensional quantum dots and One-dimensional Quantum stick and co-catalyst median surface charge The defect of process causes the photocatalysis performance of the composite catalyst to be restricted.
In view of this, special propose the application.
Summary of the invention
The purpose of the present invention is to provide a kind of composite photo-catalyst, have that extinction is high-efficient, interface charge separation effect The advantages that rate is high, interface charge compound action is weak, Photocatalyzed Hydrogen Production quantum yield is high.
Another object of the present invention is to provide a kind of preparation method of composite photo-catalyst, controllability is good, it is at low cost, Applied widely, photochemical catalyst extinction efficiency obtained and hydrogen generation efficiency are high.
What the embodiment of the present invention was realized in:
A kind of composite photo-catalyst comprising MoS2Nanometer sheet and it is adsorbed in MoS2II type CdSe/CdTe quantum of nanometer sheet Trap, II type CdSe/CdTe Quantum Well include CdSe quantum piece stratum nucleare and CdTe quantum piece shell.
A kind of preparation method of composite photo-catalyst comprising MoS will be contained2First reaction solution of nanometer sheet is added dropwise in containing II Ultrasonic disperse in second reaction solution of type CdSe/CdTe Quantum Well, obtains composite photo-catalyst.
The beneficial effect of the embodiment of the present invention is:
Composite photo-catalyst provided by the invention, firstly, the two-dimentional CdSe/CdTe Quantum Well of quantum confinement and zero dimension quantum Point is compared with One-dimensional Quantum stick, is had bigger photoabsorption cross-section, can be significantly improved the extinction efficiency of photochemical catalyst.Its Secondary, in the CdSe/CdTe Quantum Well of II type electronic structure, the conduction band and valence band of CdTe shell are respectively lower than the conduction band of CdSe core layer And valence-band level:On the one hand, for the electron delocalization of CdSe/CdTe Quantum Well into CdTe shell, this makes CdSe/CdTe Quantum Well On electronics can swimmingly be transferred to MoS2In nanometer sheet, to realize Quantum Well and MoS2The height of interface charge between nanometer sheet Effect separation;On the other hand, MoS2The conduction level of nanometer sheet be located at CdTe quantum piece shell conduction level and valence-band level it Between, the hole confinement of Quantum Well is inside CdSe core layer and CdTe shell is substantially without hole, this can effectively inhibit MoS2It receives The recombination process in rice on piece separation state electronics hole in CdSe/CdTe Quantum Well, to meet separation state electronics at MoS2 nanometers The demand of piece long-distance diffusion.The efficient interface charge separation of the CdSe/CdTe Quantum Well bring of II type electronic structure and length Journey electrons spread can substantially improve the Photocatalyzed Hydrogen Production efficiency of photochemical catalyst.Meanwhile MoS2Nanometer sheet compares table with biggish Area, two-dimentional MoS2Nanometer sheet edge has the proton reduction site of many high activities, and ultralow reaction overpotential is even It can match in excellence or beauty with traditional platinum catalyst, these characteristics make based on II type CdSe/CdTe Quantum Well and MoS2Nanometer sheet it is compound Photochemical catalyst shows excellent photocatalysis performance.
The preparation method of composite photo-catalyst provided by the invention will contain MoS2The reaction solution ultrasonic disperse of nanometer sheet is in containing In the reaction solution of II type CdSe/CdTe Quantum Well, controllability is good, at low cost, applied widely.Composite photo-catalyst obtained Pointedly enhance from Quantum Well to MoS2The electronics transfer of nanometer sheet, while weakening from MoS2Electronics of the nanometer sheet to Quantum Well It is compound, significantly improve the photocatalysis performance of composite photo-catalyst.
Detailed description of the invention
In order to illustrate the technical solution of the embodiments of the present invention more clearly, below will be to needed in the embodiment attached Figure is briefly described, it should be understood that the following drawings illustrates only certain embodiments of the present invention, therefore is not construed as pair The restriction of range for those of ordinary skill in the art without creative efforts, can also be according to this A little attached drawings obtain other relevant attached drawings.
Fig. 1 is the structural schematic diagram of composite photo-catalyst provided in an embodiment of the present invention;
Fig. 2 is the interface charge process energy diagram of composite photo-catalyst provided in an embodiment of the present invention;
Fig. 3 is the TEM figure for the CdSe/CdTe Quantum Well that the embodiment of the present invention 1 provides;
Fig. 4 is the MoS that the embodiment of the present invention 1 provides2The abosrption spectrogram of nanometer sheet;
Fig. 5 is the interface charge transmission and recombination kinetcs process light for the composite photo-catalyst that the embodiment of the present invention 1 provides Spectrogram.
Specific embodiment
It in order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below will be in the embodiment of the present invention Technical solution be clearly and completely described.The person that is not specified actual conditions in embodiment, according to normal conditions or manufacturer builds The condition of view carries out.Reagents or instruments used without specified manufacturer is the conventional production that can be obtained by commercially available purchase Product.
Composite photo-catalyst of the embodiment of the present invention and preparation method thereof is specifically described below.
Referring to Fig. 1, the present invention provides a kind of composite photo-catalyst, including MoS2Nanometer sheet and it is adsorbed in MoS2Nanometer sheet II type CdSe/CdTe Quantum Well, II type CdSe/CdTe Quantum Well includes CdSe quantum piece stratum nucleare and CdTe quantum piece shell.
The two-dimentional CdSe/CdTe Quantum Well of quantum confinement has bigger compared with zero-dimensional quantum dots and One-dimensional Quantum stick Photoabsorption cross-section, the extinction efficiency of photochemical catalyst can be significantly improved.
Referring to Fig. 2, the efficient interface charge separation of the CdSe/CdTe Quantum Well bring of II type electronic structure and long-range electricity Son diffusion can substantially improve the Photocatalyzed Hydrogen Production efficiency of photochemical catalyst.Wherein, the CdSe/CdTe Quantum Well of II type electronic structure In, the conduction level of CdTe shell is lower than CdSe core layer conduction level, and the valence-band level of CdTe shell is lower than the valence of CdSe core layer Band energy level;MoS2The conduction level of nanometer sheet is located between the conduction level and valence-band level of CdTe quantum piece shell:
On the one hand, into CdTe shell, this makes in CdSe/CdTe Quantum Well the electron delocalization of CdSe/CdTe Quantum Well Electronics can swimmingly be transferred to MoS2In nanometer sheet, to realize Quantum Well and MoS2Interface charge is efficient between nanometer sheet Separation.
On the other hand, the hole confinement of Quantum Well is inside CdSe core layer and CdTe shell is substantially without hole, this can have Effect ground inhibits MoS2The recombination process in state electronics hole in CdSe/CdTe Quantum Well is separated in nanometer sheet, to meet separation state Electronics is in MoS2The demand of nanometer sheet long-distance diffusion.
Another part important materials are co-catalysts in composite photocatalyst.Transition metal dichalcogenide is the layer of representative Shape two-dimensional material has many novel photoelectric properties, such as ultrahigh charge mobility, higher exciton binding energy etc..
It is single through inventor the study found that platelike molybdenumdisulfide is as the two-dimensional semiconductor material with excellent photoelectric properties The MoS of atomic layers thick2It is the two-dimentional direct band-gap semicondictor material that forbidden bandwidth is 1.8eV, is very suitable to for Development of Novel Nano electron device and photoelectric functional device.Simultaneously as the biggish specific surface area of stratiform MoS2, makes it have excellent light Catalytic performance.Shape MoS2Edge have many high activities proton reduction site, ultralow reaction overpotential even can To match in excellence or beauty with traditional platinum catalyst.In addition compared with platinum, MoS2Material source is abundant, cheap, has and realizes on a large scale The prospect of industrial application.
In some optional embodiments of the present invention, MoS2Nanometer sheet is the single-layer or multi-layer obtained by ultrasound removing MoS2Nanometer sheet.Further, the content of II type CdSe/CdTe Quantum Well in the composite photocatalyst is 80-95wt%, i.e., should II type CdSe/CdTe Quantum Well accounts for MoS2The 80-95% of nanometer sheet and II type CdSe/CdTe Quantum Well gross mass.So that MoS2It receives Rice piece has preferable two-dimensional structure, and MoS2Charge mobility between nanometer sheet and II type CdSe/CdTe Quantum Well is high, sharp Son combines can be high.
The present invention provides a kind of preparation method of composite photo-catalyst, including:MoS will be contained2First reaction solution of nanometer sheet The ultrasonic disperse in the second reaction solution containing II type CdSe/CdTe Quantum Well is added dropwise, obtains composite photo-catalyst.
In some specific embodiments of the present invention, the time of supersonic frequency 25KHz-130KHz, ultrasonic disperse are 1-8h, such as 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h are selectively adjusted according to actual conditions such as supersonic frequency, reaction solution concentrations.
MoS will be contained2The reaction solution ultrasonic disperse of nanometer sheet, can in the reaction solution containing II type CdSe/CdTe Quantum Well Control property is good, at low cost, applied widely.Composite photo-catalyst obtained pointedly enhances from Quantum Well to MoS2Nanometer sheet Electronics transfer, while weakening from MoS2The electronics of nanometer sheet to Quantum Well is compound, significantly improves the photocatalysis of composite photo-catalyst Performance.
Through inventor the study found that in some specific embodiments of the present invention, the solvent of the first reaction solution is selected from N- At least one of methyl pyrrolidone or acetonitrile such as can be N-Methyl pyrrolidone one, acetonitrile one or N- methyl The combination of both pyrrolidones and acetonitrile.MoS in first reaction solution2The concentration of nanometer sheet is 10-5-10-3Mol/L such as can be 10-5mol/L、2×10-5mol/L、5×10-5mol/L、8×10-5mol/L、10-4mol/L、2×10-4mol/L、5×10- 4mol/L、8×10-4mol/L、10-3Mol/L etc..The solvent of second reaction solution is in chloroform, toluene, n-hexane or heptane At least one, such as can be it is therein any one, both any combination, the combination of any three or four combination. The concentration of II type CdSe/CdTe Quantum Well is 10 in second reaction solution-4-10-3Mol/L, such as 10-4mol/L、2×10-4mol/ L、5×10-4mol/L、8×10-4mol/L、10-3Mol/L etc..Make MoS2Nanometer sheet and II type CdSe/CdTe Quantum Well have stabilization Switching performance, charge migration stablize.
Optionally, MoS2Nanometer sheet is made according to following methods:By MoS2It is scattered in ultrasound removing in N-Methyl pyrrolidone Then solution is centrifuged 10-50min with the revolving speed of 2000-5000r/min by 4-8h.Its is easy to operate, controllability is good, obtains not The MoS of stack pile2Nanometer sheet is conducive to improve the charge migration efficiency between II type CdSe/CdTe Quantum Well.
Further, II type CdSe/CdTe Quantum Well is made according to following methods:By containing for Quantum Well CdTe Shell Materials Cadmium precursor liquid is mixed with the seed solution of the piece core layer material of quantum containing CdSe under heating, obtains mixed liquor;Heating temperature 190-220 Under conditions of DEG C, the precursor liquid containing tellurium that Quantum Well CdTe Shell Materials are added dropwise into mixed liquor is reacted, and obtains II type CdSe/ CdTe Quantum Well.
Seed solution is optionally made according to following methods:
Firstly, Quantum Well CdSe core layer material cadmium source and Quantum Well CdSe core layer material selenium source are dissolved in octadecylene, take out After vacuum about 30 minutes, 1-2h is heated with 100-150 DEG C of temperature under vacuum conditions, 1h is such as heated, obtains homogeneous transparent Preprocessing solution.
Optionally, Quantum Well CdSe core layer material cadmium source in tetradecanoic acid cadmium, cadmium oxide or cadmium acetate at least one Kind.Quantum Well CdSe core layer material selenium source is selected from least one of selenium oxide or selenium powder.
In preprocessing solution, the concentration in Quantum Well CdSe core layer material cadmium source is 0.02-0.1mol/L.Quantum Well CdSe core The molar ratio of layer material cadmium source and Quantum Well CdSe core layer material selenium source is 1.8-2.2:1, it is further 2:1.
Secondly, inert gas refers to the low gas of the reactivities such as nitrogen, helium, argon gas under inert gas shield Preprocessing solution is heated to 190-220 DEG C, is such as heated to 200 DEG C by body, is rapidly added into the preprocessing solution after heating Enter cadmium acetate hydrate, optionally adds cadmium acetate dihydrate.Then the mixed solution is warming up to 230-260 DEG C of reaction 5- It is terminated after 30min with ice bath, obtains the reaction mixture of Quantum Well core layer material.
Optionally, the molar ratio of Quantum Well CdSe core layer material selenium source and cadmium acetate hydrate is 0.8-1.2:1, further Ground is 1:1.
Finally, the reaction mixture of Quantum Well core layer material obtained above is centrifuged under the revolving speed of 2000-4000rpm 10-30 minutes, separation, collection obtained CdSe quantum piece core layer material.Octadecylene is dispersed by the CdSe quantum piece core layer material In, obtain the seed solution.
In preferred embodiments of the present invention, the concentration of CdSe quantum piece core layer material is 0.06- in seed solution 0.18mmol/L。
The precursor liquid containing cadmium of Quantum Well CdTe Shell Materials is the octadecene solution in Shell Materials cadmium source and oleic acid.Wherein, Shell Materials cadmium source includes at least one of tetradecanoic acid cadmium, cadmium oxide or cadmium acetate.Quantum Well CdTe Shell Materials contain The concentration in Shell Materials cadmium source is 0.02-0.05mol/L in cadmium precursor liquid, is optionally 0.03mol/L.This contains in cadmium precursor liquid The volume ratio of oleic acid and octadecylene is optionally 1:200.
Optionally, before the precursor liquid containing cadmium of Quantum Well CdTe Shell Materials is mixed with seed solution, by Quantum Well CdTe After the precursor liquid containing cadmium of Shell Materials vacuumizes about 30min, 1-2h is heated with 100-150 DEG C of temperature under vacuum conditions, such as Heat 1h.It is heated to about 200 DEG C later, then is rapidly added to the seed solution to this and contains in cadmium precursor liquid.Seed solution with The volume ratio of the precursor liquid containing cadmium of Quantum Well CdTe Shell Materials is preferably 1-2:10, it is further 1:10.
The precursor liquid containing tellurium of Quantum Well CdTe Shell Materials is the octadecene solution of tellurium powder and tri octyl phosphine.Quantum Well CdTe The concentration of tellurium powder is 0.015-0.020mol/L in the precursor liquid containing tellurium of Shell Materials, is further 0.018mol/L.This is molten In liquid, the volume ratio of tri octyl phosphine and octadecylene is optionally about 1:12.5.
The precursor liquid containing tellurium of Quantum Well CdTe Shell Materials and the volume ratio of mixed liquor are preferably 0.4-0.7:1, into one Step ground is 0.5:1.After mixed liquor to be heated to reaction 5-10s under conditions of 190-220 DEG C, i.e., slowly by the precursor liquid containing tellurium It is added dropwise in the mixed liquor.
Further, the rate of addition of the precursor liquid containing tellurium of Quantum Well CdTe Shell Materials is 0.5-2mL/L, is added dropwise to complete 0.5-1.5h is reacted afterwards and is terminated with ice bath.Then use ethyl alcohol as precipitating reagent, II type CdSe/CdTe quantum can be obtained in centrifugation Trap.
The above-mentioned preparation method of II type CdSe/CdTe Quantum Well first prepares CdSe quantum by the way of hot solvent injection Piece stratum nucleare, then the epitaxial growth CdTe quantum piece shell outside stratum nucleare.It can be by controlling stratum nucleare and shell quantum piece respectively It grows to regulate and control the level structure of stratum nucleare and shell respectively, to accurately, effectively regulate and control CdSe/CdTe Quantum Well and MoS2It receives Interface charge process between rice piece.
By the control of CdSe/CdTe quantum well electronic structure, pointedly enhance from Quantum Well to MoS2Nanometer sheet Electronics transfer, while weakening from MoS2The electronics of nanometer sheet to Quantum Well is compound, significantly improves the photocatalysis of composite photo-catalyst Performance.
Feature and performance of the invention are described in further detail with reference to embodiments.
Embodiment 1
A kind of preparation method of composite photo-catalyst, including:
S1, tetradecanoic acid cadmium and selenium powder are dissolved in octadecylene, are vacuumized after 30min in vacuum environment with 100-150 DEG C temperature heat 1h, obtain the preprocessing solution of homogeneous transparent.Under nitrogen protection, preprocessing solution is warming up to 200 DEG C, Cadmium acetate dihydrate is rapidly added, then heats to 230-260 DEG C, is terminated after reacting 20min at such a temperature with ice bath Reaction.Reaction solution is centrifuged 20min under the revolving speed of 3000rpm, separates and collects to obtain CdSe quantum piece core layer material.By CdSe Quantum piece core layer material, which is dispersed in octadecylene, obtains seed solution.Wherein, in preprocessing solution:The concentration in cadmium source is 0.05mol/L, the molar ratio in cadmium source, selenium source and cadmium acetate hydrate are 2:1:1, CdSe quantum piece core layer material in seed solution Concentration be 0.12mmol/L.
S2, tetradecanoic acid cadmium and oleic acid are dissolved in octadecylene, obtain the precursor liquid containing cadmium of Quantum Well CdTe Shell Materials. Tellurium powder and tri octyl phosphine are dissolved in octadecylene, the precursor liquid containing tellurium of Quantum Well CdTe Shell Materials is obtained.Wherein, Quantum Well In the precursor liquid containing cadmium of CdTe Shell Materials, the concentration in cadmium source is 0.03mol/L, and the volume ratio of oleic acid and octadecylene is 1:200. In the precursor liquid containing tellurium of Quantum Well CdTe Shell Materials, the concentration of tellurium source is 0.018mol/L, the body of tri octyl phosphine and octadecylene Product is than being 1:12.5.
S3, the precursor liquid containing cadmium of Quantum Well CdTe Shell Materials obtained in S2 is vacuumized after 30min in vacuum environment In 1h heated with 100-150 DEG C of temperature.It is warming up to after 200 DEG C and quickly adds seed solution obtained in S1, obtain mixed liquor.It will Mixed liquor reacts 5-10s at a temperature of 190-220 DEG C, and Quantum Well obtained in S2 then is added dropwise with the speed of 0.5-2mL/L The precursor liquid containing tellurium of CdTe Shell Materials reacts 1h and is terminated with ice bath after being added dropwise to complete.It uses ethyl alcohol as precipitating reagent, is centrifuged To II type CdSe/CdTe Quantum Well.Wherein, the volume ratio of seed solution and the precursor liquid containing cadmium of Quantum Well CdTe Shell Materials is 1:10, the precursor liquid containing tellurium of Quantum Well CdTe Shell Materials and the volume ratio of mixed liquor are 0.5:1.
S4, by MoS2It is scattered in ultrasound removing 6h in N-Methyl pyrrolidone, then by solution with the revolving speed of 3500r/min It is centrifuged 30min, obtains MoS2Nanometer sheet.
S5, it disperses II type CdSe/CdTe Quantum Well obtained in S3 in chloroform, is made into II type CdSe/CdTe quantum The concentration of trap is 5 × 10-4The second reaction solution of mol/L.By MoS obtained in S42Nanometer sheet is scattered in N-Methyl pyrrolidone In, it is configured to MoS2The concentration of nanometer sheet is 10-4The first reaction solution of mol/L.Wherein II type CdSe/CdTe Quantum Well and MoS2 The mass ratio of nanometer sheet is 9:1.
S6, the first reaction solution is added drop-wise in the second reaction solution, with the frequency ultrasound 4h of 30KHz, is obtained based on II type CdSe/ CdTe Quantum Well and MoS2The composite photo-catalyst of nanometer sheet.
Embodiment 2
A kind of preparation method of composite photo-catalyst, difference from example 1 is that:
In S5, CdSe/CdTe Quantum Well and MoS2The mass ratio of nanometer sheet is 8:2, MoS in the first reaction solution2Nanometer sheet Concentration is 1.5 × 10-4Mol/L, the concentration of II type CdSe/CdTe Quantum Well is 2 × 10 in the second reaction solution-4mol/L。
In S6, the frequency of ultrasonic disperse is 50KHz, and the time of ultrasonic disperse is 8h.
Embodiment 3
A kind of preparation method of composite photo-catalyst, difference from example 1 is that:
In S5, II type CdSe/CdTe Quantum Well and MoS2The mass ratio of nanometer sheet is 9.5:0.5, MoS in the first reaction solution2 The concentration of nanometer sheet is 5 × 10-5Mol/L, the concentration of II type CdSe/CdTe Quantum Well is 1 × 10 in the second reaction solution-3mol/ L。
In S6, the frequency of ultrasonic disperse is 130KHz, and the time of ultrasonic disperse is 2h.
Embodiment 4
A kind of preparation method of composite photo-catalyst, difference from example 1 is that:
In S1, cadmium source is cadmium oxide, and selenium source is selenium oxide, and the concentration in cadmium source is 0.03mol/L, seed in preprocessing solution The concentration of CdSe quantum piece core layer material is 0.15mmol/L in solution.
Embodiment 5
A kind of preparation method of composite photo-catalyst, difference from example 1 is that:
In S1, cadmium source is that molar ratio is 1:1 tetradecanoic acid cadmium and cadmium acetate, selenium source are that molar ratio is 1:1 selenium oxide And selenium powder, the concentration in cadmium source is 0.08mol/L in preprocessing solution, and the concentration of CdSe quantum piece core layer material is in seed solution 0.08mmol/L。
Embodiment 6
A kind of preparation method of composite photo-catalyst, difference from example 1 is that:
In S2, cadmium source is that molar ratio is 1:1 cadmium oxide and cadmium acetate, the precursor liquid containing cadmium of Quantum Well CdTe Shell Materials The concentration in middle cadmium source is 0.05mol/L.
Test example
To the interface charge transmission rate and recombination rate and Photocatalyzed Hydrogen Production of composite photo-catalyst made from embodiment 1-6 Quantum yield is tested, and the results are shown in Table 1.
1 performance test table of table
As shown in Table 1, composite photo-catalyst provided in an embodiment of the present invention, interface electron transfer rate is in several hundred skins Second, and interface electronics recombination rate is in several to tens nano-seconds, ultrafast electron-transport and slower electronics recombination process Its interface charge separative efficiency is resulted in up to 96% or more.The Photocatalyzed Hydrogen Production quantum yield of composite photo-catalyst is up to 7.3%- 9.3%, it is significantly higher than the sub- yield of 4% or so hydrogen output of conventional photochemical catalyst.
Fig. 3 is the TEM figure for the composite photo-catalyst that the embodiment of the present invention 1 provides, and as can be seen from FIG. 3, (a) is 4 Ge Unit points The TEM of molecular layers thick (4ML) CdSe nanometer sheet schemes, and (b) schemes for the TEM of II type structure (Type II) CdSe/CdTe Quantum Well. The CdSe nanometer sheet stratum nucleare of synthesis has the thickness 1.36nm of 4 monolayers, and CdTe shell is only in the transverse direction of CdSe core layer Extend and grow, it is quantum in thickness direction that the length, width and height of the CdSe/CdTe nanometer sheet of synthesis, which are about 36nm × 14nm × 1.36nm, Confinement, show that it belongs to typical quantum-well materials.
Fig. 4 is the MoS that the embodiment of the present invention 1 provides2The abosrption spectrogram of nanometer sheet, as can be seen from FIG. 4, stratiform MoS2Point Occurs apparent exciton absorption peak not at 610nm and 670nm, which is the semi-conductor type MoS with 2H phase2, the 2H phase Semi-conductor type MoS2It is particularly suitable in photocatalysis.
Fig. 5 is the interface charge recombination kinetcs process spectrogram for the composite photo-catalyst that the embodiment of the present invention 1 provides, root According to Fig. 5 it is found that CdSe/CdTe Quantum Well and MoS2The signal of charge-separated state reaches maximum value in 1ns, later due to quantum Positive charge and MoS on trap2The compound decline for resulting in charge-separated state signal of upper negative electrical charge.It is obtained by decline kinetic curve The half-life compound to the two electronics is 12ns, this hundreds of times slower than the interface electron transfer rate of picosecond between the two, table Bright II type structure C dSe/CdTe Quantum Well provided by the invention can effectively inhibit the recombination process of interface electronics.
To sum up, composite photo-catalyst provided in an embodiment of the present invention, has that extinction is high-efficient, interface charge separative efficiency High, the advantages that interface charge compound action is weak, Photocatalyzed Hydrogen Production quantum yield is high.The preparation method controllability of composite photo-catalyst Good, at low cost, applied widely, photochemical catalyst extinction efficiency obtained and hydrogen generation efficiency are high.
Embodiments described above is a part of the embodiment of the present invention, instead of all the embodiments.Reality of the invention The detailed description for applying example is not intended to limit the range of claimed invention, but is merely representative of selected implementation of the invention Example.Based on the embodiments of the present invention, obtained by those of ordinary skill in the art without making creative efforts Every other embodiment, shall fall within the protection scope of the present invention.

Claims (10)

1. a kind of composite photo-catalyst, which is characterized in that including MoS2Nanometer sheet and it is adsorbed in the MoS2II type of nanometer sheet CdSe/CdTe Quantum Well, the II type CdSe/CdTe Quantum Well include CdSe quantum piece stratum nucleare and CdTe quantum piece shell.
2. composite photo-catalyst according to claim 1, which is characterized in that the MoS2Nanometer sheet is to be removed by ultrasound Obtained single-layer or multi-layer MoS2Nanometer sheet.
3. composite photo-catalyst according to claim 1, which is characterized in that the II type CdSe/CdTe Quantum Well is in institute Stating the content in composite photo-catalyst is 80-95wt%.
4. a kind of preparation method of composite photo-catalyst, which is characterized in that MoS will be contained2First reaction solution of nanometer sheet is added dropwise in containing Ultrasonic disperse in second reaction solution of II type CdSe/CdTe Quantum Well, obtains the composite photo-catalyst.
5. the preparation method according to claim 4, which is characterized in that the solvent of first reaction solution is selected from N- methyl pyrrole At least one of pyrrolidone or acetonitrile;
And/or MoS described in first reaction solution2The concentration of nanometer sheet is 10-5-10-3mol/L。
6. the preparation method according to claim 4, which is characterized in that the solvent of second reaction solution is selected from chloroform, first At least one of benzene, n-hexane or heptane;
And/or the concentration of II type CdSe/CdTe Quantum Well described in second reaction solution is 10-4-10-3mol/L。
7. the preparation method according to claim 4, which is characterized in that the MoS2Nanometer sheet is made according to following methods:It will MoS2It is scattered in ultrasound removing 4-8h in N-Methyl pyrrolidone, is then centrifuged solution with the revolving speed of 2000-5000r/min 10-50min。
8. the preparation method according to claim 4, which is characterized in that the II type CdSe/CdTe Quantum Well is according to following Method is made:By the precursor liquid containing cadmium of the Quantum Well CdTe Shell Materials seed with the piece core layer material of quantum containing CdSe under heating Solution mixing, obtains mixed liquor;Under conditions of 190-220 DEG C of heating temperature, Quantum Well CdTe shell is added dropwise into the mixed liquor The precursor liquid containing tellurium of material is reacted, and the II type CdSe/CdTe Quantum Well is obtained;
Optionally, before the precursor liquid containing cadmium of the Quantum Well CdTe Shell Materials is mixed with the seed solution, by the amount The precursor liquid containing cadmium of sub- trap CdTe Shell Materials heats 1-2h under vacuum conditions with 100-150 DEG C of temperature;
Optionally, the rate of addition of the precursor liquid containing tellurium of the Quantum Well CdTe Shell Materials is 0.5-2mL/L, after being added dropwise to complete Reaction 0.5-1.5h is simultaneously terminated with ice bath.
9. preparation method according to claim 8, which is characterized in that the seed solution is made according to following methods:It will The octadecene solution of Quantum Well CdSe core layer material cadmium source and Quantum Well CdSe core layer material selenium source is under vacuum conditions with 100- 150 DEG C of temperature heats 1-2h, obtains preprocessing solution;Under inert gas shield, the preprocessing solution is heated to Cadmium acetate hydrate is added after 190-220 DEG C, is terminated after being warming up to 230-260 DEG C of reaction 5-30min with ice bath, and separation product obtains The CdSe quantum piece core layer material;Octadecylene is dispersed by the CdSe quantum piece core layer material, obtains the seed solution.
10. preparation method according to claim 9, which is characterized in that Quantum Well CdSe core layer material cadmium source is selected from At least one of tetradecanoic acid cadmium, cadmium oxide or cadmium acetate;
And/or the Quantum Well CdSe core layer material selenium source is selected from least one of selenium oxide or selenium powder;
And/or in the preprocessing solution, the concentration in Quantum Well CdSe core layer material cadmium source is 0.02-0.1mol/L, institute The molar ratio for stating Quantum Well CdSe core layer material cadmium source and the Quantum Well CdSe core layer material selenium source is 1.8-2.2:1, it is described The molar ratio of Quantum Well CdSe core layer material selenium source and the cadmium acetate hydrate is 0.8-1.2:1;
And/or the concentration of CdSe quantum piece core layer material described in the seed solution is 0.06-0.18mmol/L;
And/or the precursor liquid containing cadmium of the Quantum Well CdTe Shell Materials is the octadecene solution in Shell Materials cadmium source and oleic acid, Shell Materials cadmium source includes at least one of tetradecanoic acid cadmium, cadmium oxide or cadmium acetate, the Quantum Well CdTe shell The concentration of Shell Materials cadmium source described in the precursor liquid containing cadmium of material is 0.02-0.05mol/L;
And/or the precursor liquid containing tellurium of the Quantum Well CdTe Shell Materials is the octadecene solution of tellurium powder and tri octyl phosphine, it is described The concentration of tellurium powder described in the precursor liquid containing tellurium of Quantum Well CdTe Shell Materials is 0.015-0.020mol/L;
And/or the volume ratio of the precursor liquid containing cadmium of the seed solution and the Quantum Well CdTe Shell Materials is 1-2:10;
And/or the volume ratio of the precursor liquid containing tellurium of the Quantum Well CdTe Shell Materials and the mixed liquor is 0.4-0.7:1.
CN201810602422.4A 2018-06-12 2018-06-12 composite photo-catalyst and preparation method thereof Pending CN108855149A (en)

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