A kind of preparation method of surface photovoltage signal enhancing type ZnO
Technical field
The invention belongs to catalysis material technical field, specially a kind of surface photovoltage signals for photocatalysis field
The preparation method of enhancement type ZnO.
Background technology
Nano-ZnO is a kind of very strong inorganic material of functionality, in photocatalysis, gas sensor, solar cell, photoelectricity
The fields such as device have extensive actual application value.Nano-ZnO is a kind of II-VI race's chemical combination of broad-band gap (3.37eV at room temperature)
Object semiconductor, exciton binding energy 60meV, when by ultraviolet lighting, absorption to light occurs for nano-ZnO, in valence band
Electronics is excited, and crosses forbidden transition and enters conduction band, to generate electron-hole pair.These electron-hole pairs in water can be with
Generate hydroxyl radical free radical (OH) and ultra-oxygen anion free radical (O2-), since they have strong oxidizing property, when they are in water
In when being contacted with organic pollution, organic matter is changed into free radical, is then oxidized into oxygen under active oxygen species effect
Free radical, these intermediate compounds cross energy barrier spontaneous degradation, and product is free of contamination water, carbon dioxide and mineralizer, is played
The effect of organic matter in degrading waste water.Nano-ZnO is N-type semiconductor, and property is mainly the stoichiometry by zinc and oxygen atom
Produced by proportional jitter, wherein Lacking oxygen and zinc interstitial defect provides electronics for donor level, and resistivity is very high;Pure nanometer
ZnO easily reacts with the oxygen atom in environment and keeps its characteristic more unstable;There are light induced electron-skies for ZnO catalysis materials simultaneously
Cave is to easily compound, it is seen that the problems such as optical Response difference and serious photoetch defect, constrains its application in practice.For
Meet practical application, the photogenerated charge separation effect and photocatalytic activity of nano-ZnO need to be further improved.People couple thus
It, which has done, adulterates, constructs the study on the modification such as hetero-junctions.It is to improve photoproduction to change photocatalyst surface state in numerous means
Separation of charge effect and the very effective method of photocatalytic activity.
In the factors for influencing photocatalytic activity, the separation effect of photo-generate electron-hole plays vital work
With.It is generally acknowledged that the more strong then photogenerated charge separating rate of surface photovoltage is faster, photocatalysis performance is higher.Therefore, nanometer is improved
The separation effect of ZnO photocatalyst electron-hole realizes that its industrial applications is necessary.
Invention content
The purpose of the present invention is to provide a kind of preparation methods of surface photovoltage signal enhancing type ZnO, in zinc oxide
Ammonium phosphate is added in preparation process can significantly increase the surface photovoltage signal of product zinc oxide.The object of the invention passes through following
Technical solution is realized:
A kind of preparation method of surface photovoltage signal enhancing type ZnO, includes the following steps:
1) zinc acetate is dissolved in absolute ethyl alcohol, after heating water bath stirring, (NH will be dissolved with4)3PO4Methanol solution
It is added thereto;
2) it by dissolving oxalic acid in absolute ethyl alcohol, is added in zinc acetate-ammonium phosphate solution that step 1) obtains and is vigorously stirred;
3) transfer drying, solid is ground, obtains ZnO products after calcining.
Semiconductor light-catalyst will produce surface photovoltage under light conditions.Surface photovoltage size and factors
Related, wherein photocatalyst surface state plays an important role.Appropriate ammonium phosphate is added in ZnO synthetic systems, in heating process
Middle ammonium phosphate can resolve into ammonia and phosphoric acid, and the generation of ammonia can increase the specific surface of ZnO, enhance the separation of photogenerated charge;This
Outer remaining PO4 3-Bonding action can occur with ZnO, influence ZnO built in fields, the final size for influencing surface photovoltage.
Zinc acetate can be preferably dissolved in ethyl alcohol, and ammonium phosphate can be preferably dissolved in methanol.By ammonium phosphate-methanol solution
It is added drop-wise in zinc acetate-ethanol solution, ammonium phosphate can be brought into synthetic system whereby, surface photovoltage letter is prepared
Number enhancing ZnO.
As an a kind of specific embodiment of the preparation method of surface photovoltage signal enhancing type ZnO of the present invention,
In step 1), the quality of the zinc acetate and the volume ratio of absolute ethyl alcohol are 2.19g:150ml~2.19g:100ml;It is described
(NH4)3PO4Quality and methanol solution volume ratio be 0.0025g~0.01g:20ml.
As an a kind of specific embodiment of the preparation method of surface photovoltage signal enhancing type ZnO of the present invention,
The temperature of the stirring of heating water bath described in step 1) is 60 DEG C~80 DEG C, and the time is 0.5h~2h.
As an a kind of specific embodiment of the preparation method of surface photovoltage signal enhancing type ZnO of the present invention,
In step 1), (NH4)3PO4The molar ratio N/Zn of middle N and Zn in zinc acetate is 0.5~3:100.
As an a kind of specific embodiment of the preparation method of surface photovoltage signal enhancing type ZnO of the present invention,
In step 2), the quality of the oxalic acid and the volume ratio of absolute ethyl alcohol are 2.51g:60ml~2.51g:40ml.
As an a kind of specific embodiment of the preparation method of surface photovoltage signal enhancing type ZnO of the present invention,
In step 2), the oxalic acid is dissolved in absolute ethyl alcohol in 60 DEG C~80 DEG C;The time being vigorously stirred is 2h~4h.
As an a kind of specific embodiment of the preparation method of surface photovoltage signal enhancing type ZnO of the present invention,
In step 3), the drying temperature is 80~100 DEG C, and the time is 12~14h;The calcination temperature is 400~500 DEG C, the time
For 2h~4h.
As an a kind of specific embodiment of the preparation method of surface photovoltage signal enhancing type ZnO of the present invention,
Include the following steps:
1) 2.19g zinc acetates are dissolved in 100mL~150mL absolute ethyl alcohols, heating water bath is stirred to 60 DEG C~80 DEG C
0.5h~2h;(NH will be dissolved with4)3PO420ml methanol solutions be added thereto, the molar ratio of N/Zn is 0.5%~3%;
2) 2.51g oxalic acid is dissolved at 60 DEG C~80 DEG C in the absolute ethyl alcohol of 40~60mL, step 1) is added and obtains
Zinc acetate-ammonium phosphate solution in be vigorously stirred 2h~4h;
3) product that step 2) obtains is transferred in baking oven 12~14h of baking at 80~100 DEG C, obtained solid is taken
Go out and grind, is then placed in muffle furnace after calcining 2h~4h at 400~500 DEG C and obtains ZnO products.
A kind of surface photovoltage signal enhancing type ZnO, is prepared using preparation method described above.
Compared with prior art, the invention has the advantages that:
1, surface photovoltage signal of the present invention significantly increases the preparation method of type ZnO, and easy to operate, raw material is easy to get, is easy to
It realizes and safe and reliable.
2, the present invention is in appropriate (NH4)3PO4The lower ZnO prepared of auxiliary is relatively not added with (NH4)3PO4Or addition is excessive
(NH4)3PO4The ZnO of preparation is significantly increased in the sections 300~400nm surface photoelectric signal, this is for improving photocatalytic activity
It has important practical significance.
Description of the drawings
Fig. 1 is the XRD diagram of 1 gained ZnO products of comparative example.
Fig. 2 is the surface photovoltage signal contrast of 1 products obtained therefrom of comparative example 1 and embodiment.
Fig. 3 is the surface photovoltage signal contrast of 2 products obtained therefrom of comparative example 1 and embodiment.
Fig. 4 is the surface photovoltage signal contrast of 3 products obtained therefrom of comparative example 1 and embodiment.
Fig. 5 is the surface photovoltage signal contrast of 4 products obtained therefrom of comparative example 1 and embodiment.
Fig. 6 is the surface photovoltage signal contrast of 5 products obtained therefrom of comparative example 1 and embodiment.
Fig. 7 is the XRD diagram of 5 products obtained therefrom ZnO of embodiment.
Fig. 8 is the surface photovoltage signal contrast of 6 products obtained therefrom of comparative example 1 and embodiment.
Fig. 9 is the surface photovoltage signal contrast of 7 products obtained therefrom of comparative example 1 and embodiment.
Figure 10 is the surface photovoltage signal contrast of 8 products obtained therefrom of comparative example 1 and embodiment.
Specific implementation mode
In order to make the purpose , technical scheme and advantage of the present invention be clearer, with reference to embodiments, to the present invention
It is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not used to
Limit the present invention.
In following embodiments, product ZnO crystalline phases are characterized using DX-2600X ray powder diffractions;Surface photovoltage test exists
It is tested on the surface photovoltaic spectroscopy of Jilin University's assembling, light source is xenon lamp, is amplified the signal of acquisition using lock-in amplifier, sample
Product are pressed between electro-conductive glass and metallic copper base, 300~500nm of wavelength measurement range, and specific test method and operation use
Conventional technical means.
Molar ratio described in the present embodiment is the ratio between the amount of substance.
Comparative example 1
For this comparative example that ammonium phosphate is not added in preparation process, specific preparation process is as follows:
1) 2.19g zinc acetates are dissolved in 100mL absolute ethyl alcohols, heating water bath to 60 DEG C of stirring 0.5h.
2) 2.51g oxalic acid is dissolved in the absolute ethyl alcohol of 40mL at 60 DEG C, is then added in zinc acetate solution, acutely
Stir 2h.
3) solution is transferred in baking oven 80 DEG C of baking 12h, obtained solid is taken out and ground, put into Muffle furnace
ZnO, test surfaces photovoltage are obtained after calcining 2h at 400 DEG C.
Fig. 1 is the XRD diagram of 1 products obtained therefrom of comparative example.It will be seen from figure 1 that prepared sample and ZnO standard cards number
(JCPDS 79-0206) is completely the same, illustrates that prepared sample is ZnO, and do not have miscellaneous peak, shows that sample purity is higher.
Embodiment 1
The specific preparation process of the present embodiment surface photovoltage signal enhancing type ZnO is as follows:
1) 2.19g zinc acetates are dissolved in 120mL absolute ethyl alcohols, then heating water bath is dissolved to 60 DEG C of stirring 0.5h
There is (NH4)3PO4Methanol solution be added thereto, the molar ratio of N/Zn is 0.5%.
2) 2.51g oxalic acid is dissolved at 60 DEG C in the absolute ethyl alcohol of 40mL, zinc acetate-phosphorus that step 1) obtains is added
2h is vigorously stirred in acid ammonium solution.
3) it is transferred in 80 DEG C of baking ovens and dries 12h, obtained solid is taken out and ground, put into Muffle furnace at 420 DEG C
ZnO, test surfaces photovoltage are obtained after calcining 2h.
It is compared with comparative example 1, (NH is added in embodiment 14)3PO4, and the molar ratio of N/Zn is 0.5%, calcination temperature 420
℃。
Fig. 2 is the surface photovoltage signal contrast figure of 1 products obtained therefrom of embodiment 1 and comparative example.Figure it is seen that pressing
The molar ratio of N/Zn is after 0.5% addition ammonium phosphate reacts, and in the sections 340~400nm, ZnO surface photovoltages signal significantly increases
By force, show that after ammonium phosphate is added surface photovoltage signal can be enhanced, this is conducive to improve photocatalytic activity.
Embodiment 2
The specific preparation process of the present embodiment surface photovoltage signal enhancing type ZnO is as follows:
1) zinc acetate is dissolved in absolute ethyl alcohol.Specially 2.19g zinc acetates are dissolved in 140mL absolute ethyl alcohols,
Heating water bath is to 70 DEG C of stirring 1h, then by (NH4)3PO4The solution for being dissolved in 20mL methanol is added thereto, the molar ratio of N/Zn
It is 1%.
2) 2.51g oxalic acid is dissolved at 70 DEG C in the absolute ethyl alcohol of 50mL, is added acute in zinc acetate-ammonium phosphate solution
Strong stirring 3h.
3) 90 DEG C of baking 13h in baking oven are transferred to, obtained solid is taken out and ground, is put into Muffle furnace at 440 DEG C
ZnO, test surfaces photovoltage are obtained after calcining 2h.
It is compared with comparative example 1, (NH is added in embodiment 24)3PO4, the molar ratio of N/Zn is 1%, and calcination temperature is 440 DEG C.
Fig. 3 is the surface photovoltage signal contrast figure of 1 products obtained therefrom of embodiment 2 and comparative example.It is by the molar ratio of N/Zn
After 1% is added ammonium phosphate, in the sections 300~400nm, ZnO surface photovoltage signals significantly increase.This is conducive to improve photocatalysis
Activity.
Embodiment 3
The specific preparation process of the present embodiment surface photovoltage signal enhancing type ZnO is as follows:
1) 2.19g zinc acetates are dissolved in 150mL absolute ethyl alcohols, then heating water bath will to 80 DEG C of stirring 0.5h
(NH4)3PO4The solution for being dissolved in 20mL methanol is added thereto, and the molar ratio of N/Zn is 1.5%.
2) 2.51g oxalic acid is dissolved at 80 DEG C in the absolute ethyl alcohol of 60mL, zinc acetate-phosphorus that step 1) obtains is added
2h is vigorously stirred in acid ammonium solution.
3) 100 DEG C of baking 14h in baking oven are shifted, obtained solid is taken out and ground, puts into Muffle furnace and is forged at 460 DEG C
ZnO, test surfaces photovoltage are obtained after burning 3h.
It is compared with comparative example 1, (NH is added in embodiment 34)3PO4, the molar ratio of N/Zn is 1.5%, calcination temperature 460
℃。
Fig. 4 is the surface photovoltage signal contrast figure of 1 products obtained therefrom of embodiment 3 and comparative example.It is by the molar ratio of N/Zn
After 1.5% is added ammonium phosphate reaction, in the sections 300~400nm, ZnO surface photovoltage signals significantly increase.
Embodiment 4
The specific preparation process of the present embodiment surface photovoltage signal enhancing type ZnO is as follows:
1) 2.19g zinc acetates are dissolved in 130mL absolute ethyl alcohols, heating water bath is to 80 DEG C of stirring 1h, then by (NH4)3PO4The solution for being dissolved in 20mL methanol is added thereto, and the molar ratio of N/Zn is 2%.
2) 2.51g oxalic acid is dissolved at 90 DEG C in the absolute ethyl alcohol of 50mL, zinc acetate-phosphorus that step 1) obtains is added
4h is vigorously stirred in acid ammonium solution.
3) 100 DEG C of baking 14h in baking oven are shifted, obtained solid is taken out and ground, puts into Muffle furnace and is forged at 480 DEG C
ZnO, test surfaces photovoltage are obtained after burning 4h.
It is compared with comparative example 1, (NH is added in embodiment 44)3PO4, the molar ratio of N/Zn is 2%, and calcination temperature is 480 DEG C.
Fig. 5 is the surface photovoltage signal contrast figure of 1 products obtained therefrom of embodiment 4 and comparative example.It is by the molar ratio of N/Zn
After 2% is added ammonium phosphate reaction, in the sections 300~420nm, ZnO surface photovoltage signals significantly increase.
Embodiment 5
The specific preparation process of the present embodiment surface photovoltage signal enhancing type ZnO is as follows:
1) 2.19g zinc acetates are dissolved in 110mL absolute ethyl alcohols, heating water bath is to 60 DEG C of stirring 2h, then by (NH4)3The solution that PO4 is dissolved in 20mL methanol is added thereto, and the molar ratio of N/Zn is 3%.
2) 2.51g oxalic acid is dissolved at 70 DEG C in the absolute ethyl alcohol of 60mL, is added acute in zinc acetate-ammonium phosphate solution
Strong stirring 4h.
3) 90 DEG C of baking 14h of baking oven are transferred to, obtained solid is taken out and ground, puts into Muffle furnace and is forged at 500 DEG C
ZnO, test surfaces photovoltage are obtained after burning 2h.
It is compared with comparative example 1, (NH is added in embodiment 54)3PO4, the molar ratio of N/Zn is 3%, and calcination temperature is 500 DEG C.
Fig. 6 is the surface photovoltage signal contrast figure of 1 products obtained therefrom of embodiment 5 and comparative example.It is by the molar ratio of N/Zn
After 3% is added ammonium phosphate reaction, in the sections 300~400nm, ZnO surface photovoltage signals significantly increase.
Fig. 7 is the XRD diagram of 5 products obtained therefrom of embodiment.From figure 7 it can be seen that prepared sample and ZnO standard cards number
(JCPDS 79-0206) is completely the same, illustrates that prepared sample is ZnO, and do not have miscellaneous peak, shows that sample purity is higher.
Embodiment 6
1) 2.19g zinc acetates are dissolved in 120mL absolute ethyl alcohols, heating water bath is to 60 DEG C of stirring 4h, then by (NH4)3PO4The solution for being dissolved in 20mL methanol is added thereto, and the molar ratio of N/Zn is 4%.
2) 2.51g oxalic acid is dissolved at 60 DEG C in the absolute ethyl alcohol of 40mL, is added acute in zinc acetate-ammonium phosphate solution
Strong stirring 2h.
3) 80 DEG C of baking 12h in baking oven are shifted, obtained solid is taken out and ground, puts into Muffle furnace and is forged at 400 DEG C
ZnO, test surfaces photovoltage are obtained after burning 2h.
It is compared with comparative example 1, (NH is added in embodiment 64)3PO4, the molar ratio of N/Zn is 4%.Calcination temperature is 400 DEG C.
Fig. 8 is the surface photovoltage signal contrast figure of 6 products obtained therefrom of comparative example 1 and embodiment.It is by the molar ratio of N/Zn
After 4% is added ammonium phosphate reaction, significantly reduced in the sections 300~400nm ZnO surface photovoltage signals.Show that excessive phosphorus is added
Sour ammonium auxiliary prepares ZnO, and surface photovoltage signal reduces.
Embodiment 7
1) 2.19g zinc acetates are dissolved in 140mL absolute ethyl alcohols, heating water bath is to 70 DEG C of stirring 3h, then by (NH4)3PO4The solution for being dissolved in 20mL methanol is added thereto, and the molar ratio of N/Zn is 10%.
2) 2.51g oxalic acid is dissolved at 60 DEG C in the absolute ethyl alcohol of 50mL, is added acute in zinc acetate-ammonium phosphate solution
Strong stirring 4h.
3) 80 DEG C of baking 12h in baking oven are shifted, obtained solid is taken out and ground, puts into Muffle furnace and is forged at 400 DEG C
ZnO, test surfaces photovoltage are obtained after burning 2h.
It is compared with comparative example 1, (NH is added in embodiment 74)3PO4, the molar ratio of N/Zn is 10%.Calcination temperature is 400 DEG C.
Fig. 9 is the surface photovoltage signal contrast figure of 7 products obtained therefrom of comparative example 1 and embodiment.It is by the molar ratio of N/Zn
After 10% is added ammonium phosphate reaction, significantly reduced in the sections 300~400nm ZnO surface photovoltage signals.Show that excessive phosphorus is added
Sour ammonium auxiliary prepares ZnO, and surface photovoltage signal reduces.
Embodiment 8
1) 2.19g zinc acetates are dissolved in 150mL absolute ethyl alcohols, heating water bath is to 60 DEG C of stirring 4h, then by (NH4)3PO4The solution for being dissolved in 20mL methanol is added thereto, and the molar ratio of N/Zn is 20%.
2) 2.51g oxalic acid is dissolved at 70 DEG C in the absolute ethyl alcohol of 60mL, is added acute in zinc acetate-ammonium phosphate solution
Strong stirring 4h.
3) 80 DEG C of baking 12h in baking oven are shifted, obtained solid is taken out and ground, puts into Muffle furnace and is forged at 400 DEG C
ZnO, test surfaces photovoltage are obtained after burning 2h.
It is compared with comparative example 1, (NH is added in embodiment 84)3PO4, the molar ratio of N/Zn is 20%.Calcination temperature is 400 DEG C.
Figure 10 is the surface photovoltage signal contrast figure of 8 products obtained therefrom of comparative example 1 and embodiment.It is by the molar ratio of N/Zn
After 20% is added ammonium phosphate reaction, significantly reduced in the sections 300~400nm ZnO surface photovoltage signals.Show that excessive phosphorus is added
Sour ammonium auxiliary prepares ZnO, and surface photovoltage signal reduces.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention
All any modification, equivalent and improvement etc., should all be included in the protection scope of the present invention made by within refreshing and principle.