CN115805072B - Supported AgPt alloy photocatalyst and preparation method and application thereof - Google Patents
Supported AgPt alloy photocatalyst and preparation method and application thereof Download PDFInfo
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- 239000011941 photocatalyst Substances 0.000 title claims abstract description 72
- 239000000956 alloy Substances 0.000 title claims abstract description 71
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 71
- 101100434911 Mus musculus Angpt1 gene Proteins 0.000 title claims abstract description 66
- 238000002360 preparation method Methods 0.000 title abstract description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 56
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 34
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 34
- 239000004065 semiconductor Substances 0.000 claims abstract description 31
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 28
- 239000002105 nanoparticle Substances 0.000 claims abstract description 22
- 230000001699 photocatalysis Effects 0.000 claims abstract description 17
- 239000003054 catalyst Substances 0.000 claims abstract description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 54
- 229910021529 ammonia Inorganic materials 0.000 claims description 27
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- 150000003839 salts Chemical class 0.000 claims description 22
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 239000002243 precursor Substances 0.000 claims description 11
- 238000006722 reduction reaction Methods 0.000 claims description 10
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- 239000002245 particle Substances 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 5
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- 229910052760 oxygen Inorganic materials 0.000 claims description 5
- 230000009467 reduction Effects 0.000 claims description 5
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 3
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 3
- 230000002194 synthesizing effect Effects 0.000 claims description 3
- 238000011068 loading method Methods 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 15
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- 238000003786 synthesis reaction Methods 0.000 description 16
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 14
- 239000000843 powder Substances 0.000 description 14
- 230000015572 biosynthetic process Effects 0.000 description 12
- 230000000694 effects Effects 0.000 description 12
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 8
- 238000000034 method Methods 0.000 description 8
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- 229910052786 argon Inorganic materials 0.000 description 4
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- 101710134784 Agnoprotein Proteins 0.000 description 1
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
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Abstract
The invention discloses a supported AgPt alloy photocatalyst and a preparation method and application thereof. The photocatalyst comprises: a nanoscale metal oxide semiconductor carrier, agPt alloy nanoparticles supported on the carrier; and a Schottky heterojunction is formed between the AgPt alloy nano particles and the carrier. The catalyst mainly takes AgPt alloy nano particles as a core catalytic active component, and takes a metal oxide semiconductor as a carrier and a light absorption center, wherein the AgPt alloy is uniformly loaded on the surface of the nano-scale metal oxide semiconductor in the form of nano particles, and the loaded AgPt alloy photocatalyst has stable structure and extremely high catalytic activity when applied to photocatalytic nitrogen fixation reaction.
Description
Technical Field
The invention belongs to the technical field of photocatalysts, and particularly relates to a supported AgPt alloy photocatalyst, and a preparation method and application thereof.
Background
Ammonia (NH 3) is used as a chemical raw material, has many applications in human production and life, and can be used in fields of synthetic fertilizers, polymers, pharmacy, etc. Among them, NH 3 is an important precursor for synthesizing nitrogen-containing fertilizer, which plays an important role in increasing yield of human grains. The current industrial nitrogen fixation is mainly carried out by a classical Haber-Bosch process, which needs to combine N 2 with H 2 under severe conditions (15-25 MPa, 350-550 ℃), to generate ammonia. The current reaction is about 2% of the total annual energy consumption worldwide, with annual CO 2 emissions about 3% worldwide. In addition, the feed H 2 for ammonia synthesis is mainly derived from methane reforming or water gas shift reactions, which also results in significant energy consumption and greenhouse gas emissions. Therefore, with the increasing exhaustion of fossil energy and the increasingly severe environmental situation, it is becoming particularly important to develop energy-saving and environment-friendly nitrogen fixation technology.
Solar energy is used as a clean energy source, and has the advantages of large supply quantity and sustainability. The use of photocatalytic technology to convert solar energy into chemical energy has been considered as one of the best approaches to solve the problem of future energy sources. It is therefore very interesting to develop solar photocatalytic nitrogen fixation reaction technology. The photocatalytic nitrogen fixation reaction is carried out at normal temperature and normal pressure by utilizing a photocatalyst, under the action of sunlight, N 2 and H 2 O are catalyzed to react to generate NH 3 and O 2, and the process does not need the intake of other external energy, so that the method is environment-friendly and energy-saving, and H 2 O can be used for replacing H 2 to provide a hydrogen source. However, the existing photocatalytic nitrogen fixation reaction has the problem of low catalytic efficiency, so that the development of a high-efficiency photocatalyst is a key for improving the reaction efficiency.
Disclosure of Invention
The first object of the invention is to provide a supported AgPt alloy photocatalyst.
The second aim of the invention is to provide a preparation method of the supported AgPt alloy photocatalyst.
The third object of the invention is to provide an application of the supported AgPt alloy photocatalyst in photocatalytic nitrogen reduction synthesis of ammonia.
In order to achieve the above purpose, the invention adopts the following technical scheme:
In a first aspect, the present invention provides a supported AgPt alloy photocatalyst comprising: a nanoscale metal oxide semiconductor carrier, agPt alloy nanoparticles supported on the carrier; and a Schottky heterojunction is formed between the AgPt alloy nano particles and the carrier.
Further, the nanoscale metal oxide semiconductor is TiO 2、CeO2 or In 2O3.
Further, the AgPt alloy nanoparticles were loaded at 0.6-3.5 wt.%.
Further, in the AgPt alloy nano particles, the mass ratio of Ag to Pt is 0.4-3:0.1-0.5.
Further, the particle size of the AgPt alloy nano particles is 2-5 nm.
In a second aspect, the invention provides a preparation method of the supported AgPt alloy photocatalyst, which comprises the following steps:
Adding nanoscale metal oxide semiconductor into precursor solution containing Ag salt and Pt salt, fully mixing, introducing rare gas under the condition of avoiding light to remove oxygen, and performing light irradiation treatment to obtain the nano-scale metal oxide semiconductor.
Further, in the above method, the solvent of the precursor solution containing Ag salt and Pt salt is methanol and water.
The volume ratio of the methanol to the water in the solvent is 1:4-1:10.
The conditions of the illumination treatment are as follows: the light source wavelength of the light treatment is 200-800 nm, and the light treatment time is 2-10 min.
The concentration of the precursor solution containing the Ag salt and the Pt salt is 1-50 mg/L.
In a third aspect, the invention provides an application of the supported AgPt alloy photocatalyst in photocatalytic nitrogen reduction synthesis of ammonia.
Further, the application comprises the steps of:
dispersing the supported AgPt alloy photocatalyst in water, introducing nitrogen, and then carrying out illumination to carry out reduction reaction to obtain the catalyst.
Further, the light source wavelength of the illumination is 200-800 nm.
Further, the flow rate of the nitrogen is 100-500 mL/min.
Further, the reduction reaction is carried out at a temperature of 10 to 80 ℃.
In addition, unless otherwise specified, all raw materials used in the present invention are commercially available, and any ranges recited in the present invention include any numerical value between the end values and any sub-range constituted by any numerical value between the end values or any numerical value between the end values. The percentages are mass percentages unless otherwise specified, and the solutions are aqueous solutions unless otherwise specified.
The beneficial effects of the invention are as follows:
The supported AgPt alloy photocatalyst provided by the invention mainly takes AgPt alloy nano particles as a core catalytic active component, and nano-scale metal oxide semiconductors as a carrier and a light absorption center, wherein the AgPt alloy is uniformly supported on the surface of the nano-scale metal oxide semiconductors in a nano particle form, and a Schottky heterojunction is formed between the AgPt alloy and the nano-scale metal oxide semiconductors.
The preparation method of the supported AgPt alloy photocatalyst provided by the invention can obtain alloy particles with small size, uniform dispersion and good stability, and the preparation method is high in controllability, and the loading amount of the AgPt alloy and the proportion of the two metals in the photocatalyst can be regulated by controlling the amounts of silver ions and platinum ions, so that the photocatalysts with different catalytic activities can be obtained.
The preparation method of the supported AgPt alloy photocatalyst provided by the invention is obtained by one step through simple photo-deposition, and has the advantages of simple synthesis, low cost and wide practical application prospect.
Drawings
FIG. 1 shows the X-ray powder diffraction pattern contrast chart of the supported AgPt alloy photocatalyst and TiO 2 powder prepared in examples 1-3.
Fig. 2 shows a high resolution transmission electron microscope image of the supported AgPt alloy photocatalyst prepared in example 1.
FIG. 3 shows a scanning transmission electron microscope and a corresponding elemental plane distribution diagram of the supported AgPt alloy photocatalyst prepared in example 1; wherein a shows a scanning transmission electron microscope image of the supported AgPt alloy photocatalyst prepared in example 1, and b shows an element plane distribution diagram of the supported AgPt alloy photocatalyst prepared in example 1.
FIG. 4 shows the comparison of ammonia production rates of the supported AgPt alloy photocatalysts and TiO 2 powder prepared in examples 1-3 and comparative examples 1-2 in the nitrogen fixation ammonia synthesis reaction.
FIG. 5 shows a graph of ammonia production rate versus the supported AgPt alloy photocatalyst prepared in example 1 in a nitrogen fixation ammonia synthesis reaction at different pH conditions.
FIG. 6 shows comparison of ammonia production rates of supported AgPt alloy photocatalysts prepared in examples 4-5 and comparative examples 3-4 in nitrogen fixation ammonia synthesis reactions.
Detailed Description
For a further understanding of the present invention, preferred embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are merely intended to illustrate further the features and advantages of the invention and are not limiting of the patent claims of the invention.
All the raw materials of the present invention are not particularly limited in purity, and analytical purity is preferably used in the present invention.
All the raw materials of the invention, the sources and abbreviations thereof belong to the conventional sources and abbreviations in the field of the related application, are clear and definite, and the person skilled in the art can purchase from the market or prepare the raw materials by the conventional method according to the abbreviations and the corresponding application.
The term "metal oxide semiconductor" as used herein refers to a type of metal oxide having semiconductor characteristics, and common metal oxide semiconductors include WO 3、ZnO、TiO2 and the like, and generally, conduction bands and valence bands of metal oxide semiconductors are formed by a d-orbit of a metal atom and a 2 p-orbit of an oxygen atom, respectively, so that the conduction bands are highly dispersed while the valence bands are relatively concentrated, thereby resulting in a metal oxide semiconductor having a smaller effective mass of electrons and a faster electron transport speed.
The supported AgPt alloy photocatalyst provided by the invention comprises the following components: a nanoscale metal oxide semiconductor carrier, agPt alloy nanoparticles supported on the carrier; and a Schottky heterojunction is formed between the AgPt alloy nano particles and the carrier.
The supported AgPt alloy photocatalyst takes the nano-scale metal oxide semiconductor as a carrier and a light absorption center, takes the AgPt alloy as a core catalytic active component, firstly, in the AgPt alloy, pt atoms are uniformly doped into a crystal lattice of Ag to play a role in modulating the electronic structure and the surface property of the Ag, and the existence of Pt promotes the photocatalyst to dissociate water molecules in a reaction solution and acquire activated hydrogen, and accelerates the hydrogenation rate of adsorbed nitrogen molecules. Secondly, the AgPt alloy nano particles and the nano-scale metal oxide semiconductor form a Schottky junction, so that the transfer of photo-generated electrons from the metal oxide to the alloy nano particles is facilitated, and the agglomeration of the AgPt alloy nano particles is effectively avoided by the firm combination mode of the AgPt alloy nano particles and the metal oxide semiconductor.
Further, the nanoscale metal oxide semiconductor is TiO 2、CeO2 or In 2O3. The invention discovers that the type of the nano-scale metal oxide semiconductor carrier can greatly influence the catalytic performance of the photocatalyst, and the three metal oxides provided by the invention can better generate a synergistic effect with AgPt alloy, so that the catalytic activity of the whole photocatalyst is improved. In addition, the nanoscale metal oxide semiconductor may be directly purchased in the market or prepared by conventional grinding methods.
Further, the invention provides a preparation method of the supported AgPt alloy photocatalyst, which comprises the following steps:
Adding nanoscale metal oxide semiconductor into precursor solution containing Ag salt and Pt salt, fully mixing, introducing rare gas under the condition of avoiding light to remove oxygen, and performing light irradiation treatment to obtain the nano-scale metal oxide semiconductor.
The rare gas can be common laboratory rare gas such as nitrogen or argon, and according to the specific embodiment of the invention, the oxygen removal by introducing the rare gas under the light-shielding condition is realized by the following steps: after a precursor solution containing Ag salt and Pt salt is added into a metal oxide semiconductor, the metal oxide semiconductor is placed in a quartz condensing sleeve, argon is introduced into the quartz condensing sleeve while stirring for deoxidization, the whole process is light-proof, the argon introduction time is more than 5min, and the argon flow rate is more than 100 mL/min.
The mixing is fully carried out, the mixing mode is not particularly limited in principle, and can be selected and adjusted according to actual conditions and photocatalysis requirements by a person skilled in the art, so that the photocatalytic reaction is better ensured; preferably, the metal oxide powder is ensured to be suspended and uniformly dispersed in the solution by means of ultrasound, vibration and the like. More preferably, to ensure that the photocatalytic reaction proceeds better, continuous stirring is also performed during the irradiation treatment.
Further, the solvent of the precursor solution containing the Ag salt and the Pt salt is methanol and water, and the volume ratio of the methanol to the water in the solvent is 1:4-1:10. The photocatalyst preparation process of the invention essentially utilizes one-step photo-deposition synthesis, and the addition of a proper amount of methanol into the solvent can enable the photo-deposition process to be completed rapidly and deposited thoroughly in a short time, and promote the synthesized alloy to have smaller particle size so as to improve the photo-catalytic performance.
Further, the concentration of the precursor solution containing the Ag salt and the Pt salt is 1-50 mg/L, the concentration range is favorable for the small size of the synthesized alloy, and the specific amounts of the Ag salt and the Pt salt can be determined according to the AgPt alloy amount required to be loaded.
Further, centrifugation, washing and drying of the resulting product may also be included after the light treatment. Preferably, the drying temperature is 60-90 ℃ and the time is 5-24 hours.
Furthermore, the application of the supported AgPt alloy photocatalyst in synthesizing ammonia by photocatalytic nitrogen reduction is provided, and the chemical formula of the reaction involved in the application is 2N 2+6H2O＝4NH3+3O2.
Further, the application comprises the steps of:
dispersing the supported AgPt alloy photocatalyst in water, introducing nitrogen, and then carrying out illumination to carry out reduction reaction to obtain the catalyst.
Preferably, the reduction reaction is carried out at normal pressure.
Preferably, a base may be added to the water to adjust the pH to 8 to 10.
Preferably, the mass volume ratio of the photocatalyst to the water is 5-20 mg/20-100 mL, and the flow rate of nitrogen is 100-500 mL/min.
In order to more clearly illustrate the present invention, the present invention will be further described with reference to preferred embodiments and the accompanying drawings. Like parts in the drawings are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and that this invention is not limited to the details given herein.
Example 1
A supported AgPt alloy photocatalyst comprising the steps of:
1) 7.9mg of AgNO 3 and 13.3mg of H 2PtCl6·6H2 O were dissolved in 5mL of ultrapure water, respectively, to obtain a solution A and a solution B, respectively.
2) A mixed solution of 25mL of ultrapure water and 5mL of methanol was prepared in a quartz reactor, then 20mg of TiO 2 powder (with a dimension of 20-40 nm) was added to the quartz reactor, then 400. Mu.L of the A solution and 60. Mu.L of the B solution were added, and ultrasonic dispersion was performed for 5 minutes to obtain a quartz reactor containing a suspension.
3) The quartz reactor containing the suspension was placed in a quartz jacket with circulating condensate water to maintain a constant temperature of 25 ℃. The suspension was continuously stirred in the dark while high purity Ar was bubbled through the suspension for 5min to purge the system of oxygen. Then, the reaction system was irradiated with a 300W xenon lamp as a light source (PLS-SXE 300DUV, light source wavelength range of 200-800 nm) while high purity Ar was bubbled through the suspension for 5min under continuous stirring. Stopping illumination, centrifugally separating the solid product, washing the solid product twice by using ultrapure water, and finally drying at 60 ℃ for 12 hours to obtain the photocatalyst, namely Ag2Pt0.3.
As can be seen from fig. 2, the AgPt alloy particles in the photocatalyst obtained in this example are uniformly supported on the surface of TiO 2, where the particle size of the AgPt alloy is 2-5 nm.
As can be seen from fig. 3, in the photocatalyst obtained in this example, ag (shown in the yellow part of b in fig. 3) and Pt (shown in the green part of b in fig. 3) both elements were uniformly distributed in the metal particles, and it was also found that the metal particles in the photocatalyst of the present invention were AgPt alloy structures.
Example 2
The difference from example 1 was only that the amount of the solution B added in step 2) was 20. Mu.L, and the finally obtained photocatalyst was designated as Ag2Pt0.1.
Example 3
The difference from example 1 was only that the amount of the solution B added in step 2) was 100. Mu.L, and the finally obtained photocatalyst was designated as Ag2Pt0.5.
Example 4
The difference from example 1 is only that In step 2) the TiO 2 powder is replaced equally by an In 2O3 powder (scale 20-40 nm) and the finally obtained photocatalyst is denoted ap@in 2O3.
Example 5
The difference from example 1 is only that in step 2) the TiO 2 powder was replaced equally with CeO 2 powder (scale 20-40 nm) and the finally obtained photocatalyst was noted ap@ceo 2.
Comparative example 1
The difference from example 1 was only that in step 2), no solution B was added and the photocatalyst obtained was designated Ag2.
Comparative example 2
The difference from example 1 was only that in step 2) no solution A was added and the photocatalyst obtained was designated Pt0.3.
Comparative example 3
The difference from comparative example 1 was only that In step 2), 20mg of TiO 2 powder was changed to 20mg of In 2O3 powder (scale 20-40 nm), and the obtained photocatalyst was designated Ag@In 2O3.
Comparative example 4
The difference is only that in step 2), 20mg of TiO 2 powder is changed to 20mg of CeO 2 powder (scale 20-40 nm), and the obtained photocatalyst is denoted as Ag@CeO 2.
Test example 1
XRD spectra of the supported AgPt alloy photocatalyst and TiO 2 powder prepared in comparative examples 1 to 3 are shown in FIG. 1.
Conclusion: as can be seen from FIG. 1, the photocatalysts prepared in examples 1-3 are consistent with the peak signals of the X-ray powder diffraction patterns of TiO 2, which shows that the synthesis process has no obvious influence on the crystal structure of TiO 2.
Test example 2
Different photocatalysts are respectively applied to the photocatalytic nitrogen fixation synthesis of ammonia, and specifically comprise the following steps:
5mg of the photocatalyst was added to a reaction apparatus containing 30mL of ultrapure water, and the mixture was stirred with ultrasound for 10 minutes to uniformly disperse. Under dark conditions, high-purity nitrogen is continuously introduced into the reaction device for 10min. The circulating condensate water was turned on, and the photocatalytic reaction was carried out for 30min with a 300W xenon lamp as a light source (PLS-SXE 300DUV, light source wavelength range 200-800 nm) with continuous nitrogen introduction and stirring. After the completion of the reaction, 2mL of the reaction mixture was taken out, and after the catalyst was filtered off, the ammonia concentration in the product was measured by ion chromatography.
The results of the ammonia production rates of the photocatalysts and TiO 2 powder (with dimensions of 20-40 nm) prepared in comparative examples 1-3 and comparative examples 1-2 in the above-mentioned nitrogen-fixing ammonia synthesis reaction are shown in FIG. 4.
The ammonia production rates of the photocatalysts prepared in comparative examples 5 to 6 and comparative examples 3 to 4 in the above-mentioned nitrogen-fixing synthetic ammonia reaction are shown in FIG. 6.
Conclusion: as can be seen from FIG. 4, (1) the activity of the photocatalyst Ag2Pt0.3 prepared in example 1 was 38.4. Mu. Mol.g -1·h-1; the activity of the photocatalyst Ag2Pt0.1 prepared in example 2 was 18.7. Mu. Mol.g -1·h-1; the activity of the photocatalyst Ag2Pt0.5 obtained in example 3 was 23.6. Mu. Mol. G -1·h-1. From this, it can be derived that: the photocatalysts prepared in examples 1-3 all have good photocatalytic ammonia synthesis performance, and the content of Pt in the alloy has great influence on the catalytic performance, so that the catalytic performance of the photocatalysts can be optimized by adjusting the content of Pt. (2) The activity of the photocatalyst Ag2 prepared in comparative example 1 was 12.0. Mu. Mol.g -1·h-1; the photocatalyst Pt0.3 produced in comparative example 2 had a synthetic ammonia activity of 5.8. Mu. Mol. G -1·h-1;TiO2 and a synthetic ammonia activity of 5.0. Mu. Mol. G -1·h-1. From this, it can be derived that: the supported AgPt alloy structure has obvious performance advantages compared with the supported single metal catalyst or pure TiO 2, namely, the active site of the AgPt alloy has great promotion effect on the photocatalytic nitrogen fixation reaction.
As is clear from FIG. 6, the ammonia synthesis activity of (1) the photocatalyst AP@In 2O3 prepared in example 4 was 46.3. Mu. Mol.g -1·h-1, and the ammonia synthesis activity of the photocatalyst AP@CeO 2 prepared in example 5 was 25.7. Mu. Mol.g -1·h-1. From this, it can be derived that: agPt alloy photocatalyst loaded by CeO 2 or In 2O3 serving as a carrier and a photosensitizer has excellent photocatalytic nitrogen fixation performance. (2) The ammonia synthesis activity of ag@In 2O3 of comparative example 3 was 2.7 μmol·g -1·h-1, significantly weaker than that of AP@In 2O3. The synthetic ammonia activity of Ag@CeO 2 of comparative example 4 was 11.8. Mu. Mol.g -1·h-1, significantly weaker than AP@CeO 2. From this, it can be derived that: for different metal oxide semiconductor carriers, the supported AgPt alloy structure has obvious performance advantages compared with a supported single metal catalyst.
Test example 3
The photocatalyst of example 1 was applied to photocatalytic nitrogen fixation synthesis of ammonia, and the specific procedure was the same as in test example 2, except that 30mL of ultrapure water was changed to 30mL of NaOH solution at ph=10.
As can be seen from FIG. 5, the photocatalytic nitrogen fixation performance of Ag2Pt0.3 in a weakly alkaline environment with pH=10 is 43.3. Mu. Mol.g -1·h-1, even slightly higher than in a neutral environment. The catalyst can still maintain high activity under the weak alkaline environment.
It should be understood that the foregoing examples of the present invention are provided merely for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention, and that various other changes and modifications may be made therein by one skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.
Claims (10)
1. An application of a supported AgPt alloy photocatalyst in synthesizing ammonia by photocatalytic nitrogen reduction, which is characterized by comprising the following steps of: a nanoscale metal oxide semiconductor carrier, agPt alloy nanoparticles supported on the carrier; a Schottky heterojunction is formed between the AgPt alloy nano particles and the carrier;
the loading amount of the AgPt alloy nano particles is 0.6-3.5 wt.%; in the AgPt alloy nano particles, the mass ratio of Ag to Pt is 0.4-3:0.1-0.5;
The photocatalyst is prepared by the following steps:
Adding nanoscale metal oxide semiconductors into precursor solution containing Ag salt and Pt salt, fully mixing, introducing rare gas under the condition of avoiding light to remove oxygen, and performing light irradiation treatment to obtain the nano-scale metal oxide semiconductor;
the application comprises the following steps: dispersing the supported AgPt alloy photocatalyst in water, introducing nitrogen, and then carrying out illumination to carry out reduction reaction to obtain the catalyst.
2. The use according to claim 1, wherein the nanoscale metal oxide semiconductor is TiO 2、CeO2 or In 2O3.
3. The use according to claim 1, characterized in that the AgPt alloy nanoparticles have a particle size of 2-5 nm.
4. The use according to claim 1, wherein the solvents of the precursor solutions containing Ag salts and Pt salts are methanol and water.
5. The use according to claim 4, wherein the volume ratio of methanol to water in the solvent is 1:4 to 1:10.
6. The use according to claim 1, wherein the conditions of the light treatment are: the light source wavelength of the light treatment is 200-800 nm, and the light treatment time is 2-10 min.
7. The use according to claim 1, wherein the concentration of the precursor solution containing Ag salt and Pt salt is 1-50 mg/L.
8. The use according to claim 1, wherein,
The wavelength of the light source for illumination is 200-800 nm.
9. The use according to claim 1, wherein the flow rate of nitrogen is 100-500 mL/min.
10. The use according to claim 1, wherein the reduction is carried out at a temperature of 10 to 80 ℃.
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Citations (2)
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| CN103846086A (en) * | 2014-03-05 | 2014-06-11 | 四川大学 | Catalyst for preparing nitric oxides through catalytic ammonia oxidation |
| CN106268727A (en) * | 2015-05-26 | 2017-01-04 | 中国科学院金属研究所 | Titanium dioxide based photocatalytic material of noble metal nano particles selective modification and its preparation method and application |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103846086A (en) * | 2014-03-05 | 2014-06-11 | 四川大学 | Catalyst for preparing nitric oxides through catalytic ammonia oxidation |
| CN106268727A (en) * | 2015-05-26 | 2017-01-04 | 中国科学院金属研究所 | Titanium dioxide based photocatalytic material of noble metal nano particles selective modification and its preparation method and application |
Non-Patent Citations (3)
| Title |
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| Preparation, characterization and photocatalytic activity of TiO2microspheres decorated by bimetallic nanoparticles;nanoparticlesE. Grabowska et al.;《Journal of Molecular Catalysis A: Chemical》;第424卷;第241-253页 * |
| TiO2 nanorods loaded with AuePt alloy nanoparticles for the photocatalytic oxidation of benzyl alcohol;Xiong-Fei Zhang et al.;《Journal of Physics and Chemistry of Solids》;第126卷;第27-32页 * |
| Xiong-Fei Zhang et al..TiO2 nanorods loaded with AuePt alloy nanoparticles for the photocatalytic oxidation of benzyl alcohol.《Journal of Physics and Chemistry of Solids》.2018,第126卷第27-32页. * |
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