CN107308973B - Basic cobalt phosphate nanoneedle composite LTON photocatalyst and preparation method and application thereof - Google Patents
Basic cobalt phosphate nanoneedle composite LTON photocatalyst and preparation method and application thereof Download PDFInfo
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- CN107308973B CN107308973B CN201710510420.8A CN201710510420A CN107308973B CN 107308973 B CN107308973 B CN 107308973B CN 201710510420 A CN201710510420 A CN 201710510420A CN 107308973 B CN107308973 B CN 107308973B
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- 239000011941 photocatalyst Substances 0.000 title claims abstract description 58
- 239000002131 composite material Substances 0.000 title claims abstract description 49
- 229910000152 cobalt phosphate Inorganic materials 0.000 title claims abstract description 45
- ZBDSFTZNNQNSQM-UHFFFAOYSA-H cobalt(2+);diphosphate Chemical compound [Co+2].[Co+2].[Co+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O ZBDSFTZNNQNSQM-UHFFFAOYSA-H 0.000 title claims abstract description 45
- 238000002360 preparation method Methods 0.000 title claims abstract description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000001301 oxygen Substances 0.000 claims abstract description 32
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 32
- 238000011065 in-situ storage Methods 0.000 claims abstract description 8
- 239000000843 powder Substances 0.000 claims description 90
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 50
- 239000007864 aqueous solution Substances 0.000 claims description 44
- 238000001816 cooling Methods 0.000 claims description 42
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 36
- 238000001354 calcination Methods 0.000 claims description 34
- 239000002243 precursor Substances 0.000 claims description 34
- 238000006243 chemical reaction Methods 0.000 claims description 31
- 238000003756 stirring Methods 0.000 claims description 31
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 30
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 30
- 229910019142 PO4 Inorganic materials 0.000 claims description 23
- 239000000243 solution Substances 0.000 claims description 23
- 238000010438 heat treatment Methods 0.000 claims description 22
- 239000000084 colloidal system Substances 0.000 claims description 20
- 239000010453 quartz Substances 0.000 claims description 20
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 20
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 claims description 20
- 230000001699 photocatalysis Effects 0.000 claims description 15
- 238000001035 drying Methods 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 239000008367 deionised water Substances 0.000 claims description 11
- 229910021641 deionized water Inorganic materials 0.000 claims description 11
- 239000000126 substance Substances 0.000 claims description 11
- YASYEJJMZJALEJ-UHFFFAOYSA-N Citric acid monohydrate Chemical compound O.OC(=O)CC(O)(C(O)=O)CC(O)=O YASYEJJMZJALEJ-UHFFFAOYSA-N 0.000 claims description 10
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 10
- 229960002303 citric acid monohydrate Drugs 0.000 claims description 10
- 238000000354 decomposition reaction Methods 0.000 claims description 10
- 230000000694 effects Effects 0.000 claims description 10
- GJKFIJKSBFYMQK-UHFFFAOYSA-N lanthanum(3+);trinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O GJKFIJKSBFYMQK-UHFFFAOYSA-N 0.000 claims description 10
- 239000002244 precipitate Substances 0.000 claims description 10
- 238000005406 washing Methods 0.000 claims description 10
- 238000004321 preservation Methods 0.000 claims description 9
- 238000001132 ultrasonic dispersion Methods 0.000 claims description 7
- 230000001788 irregular Effects 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 2
- 230000003197 catalytic effect Effects 0.000 abstract description 3
- 238000006555 catalytic reaction Methods 0.000 abstract description 3
- 238000001027 hydrothermal synthesis Methods 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 17
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 16
- 229910021529 ammonia Inorganic materials 0.000 description 16
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 12
- 239000003054 catalyst Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 229910052698 phosphorus Inorganic materials 0.000 description 7
- 241000282414 Homo sapiens Species 0.000 description 6
- 238000002441 X-ray diffraction Methods 0.000 description 6
- 238000010521 absorption reaction Methods 0.000 description 6
- 238000013329 compounding Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 238000011161 development Methods 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 238000001228 spectrum Methods 0.000 description 5
- 238000001237 Raman spectrum Methods 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000003912 environmental pollution Methods 0.000 description 3
- 238000002329 infrared spectrum Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000006798 recombination Effects 0.000 description 3
- 238000005215 recombination Methods 0.000 description 3
- 238000001878 scanning electron micrograph Methods 0.000 description 3
- 238000000026 X-ray photoelectron spectrum Methods 0.000 description 2
- 238000000862 absorption spectrum Methods 0.000 description 2
- 238000010668 complexation reaction Methods 0.000 description 2
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- 229910003077 Ti−O Inorganic materials 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt(II) nitrate Inorganic materials [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000006174 pH buffer Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000007146 photocatalysis Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910001961 silver nitrate Inorganic materials 0.000 description 1
- 238000000527 sonication Methods 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000004083 survival effect Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000002371 ultraviolet--visible spectrum Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/24—Nitrogen compounds
-
- B01J35/39—
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/08—Heat treatment
- B01J37/10—Heat treatment in the presence of water, e.g. steam
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
- C01B13/02—Preparation of oxygen
- C01B13/0203—Preparation of oxygen from inorganic compounds
- C01B13/0207—Water
Abstract
The invention provides a basic cobalt phosphate nanoneedle composite LTON photocatalyst and a preparation method and application thereof2N; then through hydrothermal method on LaTiO2In-situ growth of Co on N3(OH)2(HPO4)2And (5) nano needles to obtain the target product. The basic cobalt phosphate nanoneedle composite LTON photocatalyst prepared by the invention has special appearance, and LaTiO2N and Co3(OH)2(HPO4)2A special heterojunction is constructed between the nano needles, so that Co3(OH)2(HPO4)2Nano needle compounded LaTiO2Pure LaTiO compared with N photocatalyst2N has better visible light catalytic oxygen generation performance, and realizes the pure LaTiO2And the oxygen generation performance of the N visible light catalysis is improved.
Description
Technical Field
The invention belongs to the technical field of photocatalytic water decomposition by sunlight, and relates to a photocatalytic water decomposition oxygen generation technology, namely a photocatalytic oxygen generation technology taking water as a raw material under the condition of simulating sunlight visible light irradiation, in particular to a method for generating oxygen by utilizing water under the condition of LTON (LaTiO)2In-situ hydrothermal growth of basic cobalt phosphate (Co) on N)3(OH)2(HPO4)2) A method of nano-needle and application of photocatalysis oxygen production.
Background
Energy is a material resource which can provide human beings with energy in a certain form in nature. For one country, energy is an important material basis for national economy, and future national fates depend on the control of energy. In a sense, the development of human society is not independent of the emergence of high-quality energy and the use of advanced energy technologies. At present, because traditional fossil energy sources largely used by petroleum, coal and the like are exhausted, and a new energy production supply system cannot be established, a series of problems are caused in the aspects of transportation, financial industry, industrial and commercial industry and the like, namely energy crisis. Meanwhile, a large amount of traditional fossil energy is used, so that a series of environmental pollution such as global warming and haze which seriously affect human survival are caused. Solving the energy crisis and the environmental pollution related to the energy crisis is the urgent need of the world and the human world at present, and is a great problem influencing the human development. Therefore, the development of new energy with high efficiency, abundance, reproducibility and cleanness gradually converts the energy system with traditional fossil energy as the leading energy system into a new energy system, which is not only the most promising approach to solve energy crisis and environmental pollution, but also an urgent task for human development.
Solar energy is theoretically regarded as inexhaustible clean energy, and the effective utilization of solar energy is a promising direction for solving the energy crisis. Based on factors such as sustainable development and renewable energy sources, raw materials such as water and biomass are selected, and the solar energy is utilized to decompose water, so that a feasible means for utilizing solar energy is provided. The principle of photocatalytic water splitting is as follows. Under the irradiation of light with proper energy, the photocatalyst absorbs light energy and is excited to generate photo-generated electron and hole pairs. Then, the generated electron and hole pairs migrate to the surface of the photocatalyst and undergo an oxidation-reduction reaction with water to obtain hydrogen and oxygen. In order to realize the aim of hydrogen production by solar photocatalytic water decomposition, the key point is to develop a high-efficiency, low-cost and stable visible-light-driven photocatalyst. Although various visible light-responsive photocatalysts have been reported in the current research, the research results still deviate from the requirements of high efficiency, low cost and the like.
Nitrogen oxide photocatalysts, simply speaking, in which part of O in the corresponding oxide is replaced by N, not only cause the wide-bandgap photocatalyst to expandTo the visible region and to convert its crystal structure, which is completely different from the corresponding oxide crystal structure, unlike N doping. The valence band of the oxynitride photocatalyst is composed of O2p and N2 p orbitals, since the electronegativity of N is less than that of O (χ O)>χ N), the orbital level of N will be higher than the corresponding O orbital, so the valence band position of the oxynitride will be higher than the corresponding valence band position of the oxide, while the conduction band position will be substantially unchanged. Therefore, the oxynitride has a smaller band gap and can absorb visible light with the wavelength of 500-600 nm. The nitrogen oxide photocatalyst mainly contains d0Configurational Ti4+、Nb5+And Ta5+The photocatalyst of the metal ions carries out visible light photocatalytic decomposition of water to produce hydrogen and oxygen in a system containing a sacrificial agent, and even has the function of visible light photocatalytic decomposition of pure water to produce hydrogen and oxygen. Wherein, LaTiO2N is a very potential nitrogen oxide visible light photocatalyst. LaTiO 22N is composed of elements with abundant storage, has a narrow band gap (2.1eV), can fully absorb and utilize visible light with the wavelength of below 600nm, has proper conduction band and valence band, and is researched and found to be capable of respectively and efficiently producing hydrogen and oxygen in different sacrificial agent systems under the irradiation of the visible light, thereby having great research value. Semiconductor recombination is a means for promoting the effective separation and migration of photon-generated carriers, so that the nitrogen oxide photocatalyst LaTiO can be improved by being compounded with other semiconductors2Photocatalytic properties of N.
Disclosure of Invention
The invention aims to provide a basic cobalt phosphate nanoneedle composite LTON photocatalyst and a preparation method and application thereof, and the method is applied to LaTiO2In-situ hydrothermal growth of Co on N3(OH)2(HPO4)2The nanometer needle is used for constructing the photocatalyst with special microscopic appearance and composite structure and realizing the improvement of the visible light catalytic oxygen production performance.
In order to achieve the purpose, the invention adopts the technical scheme that:
a preparation method of basic cobalt phosphate nanoneedle composite LTON photocatalyst comprises the following specific steps:
1) preparation of LaTiO2N powder
Adding A mol of citric acid monohydrate, B mol of tetraisopropyl titanate, C mol of lanthanum nitrate hexahydrate and D mol of ethylene glycol into E mL of methanol, and stirring and dissolving to obtain a transparent colloid, wherein A: B: E ═ 0.04-0.1: (0.001-0.02): 50-200, B: C ═ 1:1, and A: D ═ 1: 4; carrying out oil bath on the transparent colloid at the temperature of 60-90 ℃ for 2-6 h, then carrying out oil bath at the temperature of 120-150 ℃ for 18-24 h, and then naturally cooling to room temperature to obtain a gel substance; drying the gel substance into powder, and transferring the powder into an ash furnace for calcining to obtain precursor powder; finally, ammonia gas post-treatment is carried out on the precursor powder to obtain LaTiO2N powder;
2) in LaTiO2In-situ hydrothermal growth of Co on N powder3(OH)2(HPO4)2Nano needle
F g LaTiO2Adding N powder into deionized water, ultrasonically dispersing uniformly, and adding (NH) with P content of G mmol under stirring4)3PO4Mixing the aqueous solution, adding Co (NO) with H mmol of Co3)2And (3) obtaining a reaction solution by using an aqueous solution, wherein F is G (0.06-0.606) and G is 0.1-0.4, H is 2:3, continuously stirring the reaction solution at room temperature for 1-2H, transferring the reaction solution to a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 4-8H, naturally cooling to room temperature, washing and drying the precipitate obtained by the reaction, and thus obtaining the basic cobalt phosphate nanoneedle composite LTON photocatalyst.
The drying in the step 1) is to heat the gel substance in an oven at 200 ℃ for 2-6 h, and then naturally cool the gel substance to room temperature to obtain powder.
The calcination in the ash furnace in the step 1) is specifically as follows: transferring the powder to an ash furnace, calcining at 250 ℃ for 1-2 h, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1-2 h, then continuously heating to 500 ℃, calcining for 12-24 h, and finally naturally cooling to room temperature to obtain precursor powder.
The ammonia gas post-treatment of the precursor powder in the step 1) specifically comprises the following steps: placing the precursor powder in a quartz boat, and moving the quartz boat into an alumina tube typeTreating the mixture in a furnace at 950 ℃ for 15-20 h in an ammonia atmosphere at the ammonia flow rate of 300-500 mL/min, and cooling to room temperature after treatment to obtain LaTiO2And (4) N powder.
In the step 2), every 0.06-0.606 g of LaTiO is added2And adding the N powder into 60mL of deionized water, wherein the time required for uniform ultrasonic dispersion is 5-20 min.
Adding (NH) in the step 2)4)3PO4The time required for stirring the aqueous solution uniformly is 1-10 min.
(NH) in said step 2)4)3PO4Aqueous solution and Co (NO)3)2The concentration of the aqueous solution was 0.1mol/L, (NH)4)3PO4The addition amount of the aqueous solution is 1000-4000 mu L, and Co (NO)3)2The addition amount of the aqueous solution is 1500-6000 mu L.
The basic cobalt phosphate nanoneedle composite LTON photocatalyst prepared by the preparation method is in the shape of irregular blocky agglomerate LaTiO with porous surface2N surface grows Co3(OH)2(HPO4)2The basic cobalt phosphate nanoneedle is compounded with Co in LTON photocatalyst3(OH)2(HPO4)2With LaTiO2The mass percentage of N is x, x is more than 0 and less than or equal to 70 percent.
The oxygen production activity of the basic cobalt phosphate nanoneedle composite LTON photocatalyst in oxygen production by photocatalytic decomposition of water under visible light is 1.02-1.49 mmol.h-1·gcat -1。
The basic cobalt phosphate nanoneedle composite LTON photocatalyst is applied to photocatalytic decomposition of water under visible light to prepare oxygen.
Compared with the prior art, the invention has the beneficial effects that:
the preparation method of the basic cobalt phosphate nanoneedle composite LTON photocatalyst provided by the invention comprises the steps of firstly synthesizing LaTiO by utilizing a polymerization complexation method and a high-temperature ammonia gas post-treatment means2N (LTON) powder, then hydrothermal reaction on LaTiO2In-situ growth of basic cobalt phosphate (Co) on N3(OH)2(HPO4)2) And (4) nano needles to obtain the basic cobalt phosphate nano needle composite LTON photocatalyst. The invention provides a method for preparing LaTiO2Growing Co on N3(OH)2(HPO4)2Effective means of nano needle can promote LaTiO2Effective combination of N and basic cobalt phosphate, and regulation and control of Co3(OH)2(HPO4)2The micro-morphology of (2). The invention firstly proposes that2In-situ hydrothermal growth of Co on N3(OH)2(HPO4)2The method of the nanometer needle is adopted, so that the basic cobalt phosphate nanometer needle composite LTON photocatalyst with special microscopic appearance and composite structure is constructed, and LaTiO2N and Co3(OH)2(HPO4)2A special heterojunction is constructed between the nano needles, so that Co3(OH)2(HPO4)2Nano needle compounded LaTiO2Pure LaTiO compared with N photocatalyst2N has better visible light catalytic oxygen generation performance, and realizes the pure LaTiO2And the oxygen generation performance of the N visible light catalysis is improved.
The basic cobalt phosphate nanoneedle composite LTON photocatalyst provided by the invention is prepared by adding LaTiO into a catalyst2In-situ hydrothermal growth of Co on N3(OH)2(HPO4)2The basic cobalt phosphate nanoneedle composite LTON photocatalyst obtained by nanoneedles has special appearance and composite structure, and is marked as CoPi-H/LTON-x, wherein x represents Co3(OH)2(HPO4)2With LaTiO2And x is more than 0 and less than or equal to 70 percent. Due to LaTiO2N and Co3(OH)2(HPO4)2A special heterojunction is formed between the nano needles, so that the Co of the invention3(OH)2(HPO4)2Nano needle compounded LaTiO2Pure LaTiO compared with N photocatalyst2N has better visible light catalysis oxygen generation performance, can be applied to photocatalytic water decomposition oxygen generation under visible light, and has good application prospect.
Drawings
FIG. 1 is an X-ray diffraction pattern of CoPi-H/LTON-33% obtained in example 1, LTON obtained in comparative example 1, and CoPi-H obtained in comparative example 2;
FIG. 2 is a scanning electron micrograph in which (a) is LTON obtained in comparative example 1, (b) is CoPi-H/LTON-33% obtained in example 1, and (c) is CoPi-H obtained in comparative example 2;
FIG. 3 is a UV-visible absorption spectrum of CoPi-H/LTON-33% obtained in example 1, LTON obtained in comparative example 1, and CoPi-H obtained in comparative example 2;
FIG. 4 is an IR spectrum of CoPi-H/LTON-33% obtained in example 1, LTON obtained in comparative example 1, and CoPi-H obtained in comparative example 2;
FIG. 5 is a Raman spectrum of LTON obtained in comparative example 1 and CoPi-H/LTON-33% obtained in example 1;
FIG. 6 is an X-ray photoelectron spectrum wherein (a) is a Ti 2p spectrum of CoPi-H/LTON-33% obtained in example 1 and LTON obtained in comparative example 1, and (b) is a Co2p spectrum of CoPi-H/LTON-33% obtained in example 1 and CoPi-H obtained in comparative example 2;
FIG. 7 is a graph of visible light catalyzed oxygen production for CoPi-H/LTON-33% from example 1, LTON from comparative example 1, and CoPi-H from comparative example 2, oxygen production conditions: photocatalyst 0.05g, pH buffer: lanthanum oxide 0.2g, sacrificial agent solution: 200mL of 0.02mol/L silver nitrate aqueous solution, light source: 300W Xe lamp (lambda is more than or equal to 420 nm).
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings and preferred embodiments of the invention.
Comparative example 1: preparation of LaTiO2N powder
0.04mol of citric acid monohydrate, 0.01mol of tetraisopropyl titanate, 0.01mol of lanthanum nitrate hexahydrate and 0.16mol of ethylene glycol are sequentially added into 50mL of methanol and stirred to be dissolved, so that transparent colloid is obtained. The clear colloid was oil-bathed at 70 ℃ for 4h, followed by 130 ℃ for 20h, and then allowed to cool to room temperature naturally to give a brown gel mass. Heating the brown gel material in an oven at 200 deg.C for 4h, and naturally cooling to room temperature to obtainBrown black powder. And transferring the brownish black powder into an ash furnace, calcining for 1h at 250 ℃, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1h, continuously heating to 500 ℃ and calcining for 12h, and naturally cooling to room temperature to ensure that organic matters in the brown black powder are removed, so that white precursor powder is obtained. Carrying out high-temperature ammonia gas post-treatment on the white precursor powder: placing the white precursor powder in a quartz boat, moving the quartz boat into an alumina tube furnace, treating for 15h at 950 ℃ in an ammonia atmosphere (the flow rate of ammonia is controlled to be 500mL/min), and cooling to room temperature to obtain LaTiO2N red powder, noted LTON.
Comparative example 2: preparation of basic cobalt phosphate Co3(OH)2(HPO4)2
35mL of 0.86mol/L Co (NO) were added under stirring3)2The aqueous solution was added dropwise to 35mL of 0.57mol/L (NH)4)3PO4Stirring in water solution for 2h, transferring to hydrothermal kettle, keeping at 200 deg.C for 6h, self-heating and cooling to room temperature, centrifuging the obtained bluish purple precipitate with water and ethanol, washing and drying to obtain Co3(OH)2(HPO4)2And is marked as CoPi-H.
Example 1:
1) 0.04mol of citric acid monohydrate, 0.01mol of tetraisopropyl titanate, 0.01mol of lanthanum nitrate hexahydrate and 0.16mol of ethylene glycol are sequentially added into 50mL of methanol and stirred to be dissolved, so that transparent colloid is obtained. The clear colloid was oil-bathed at 70 ℃ for 4h, followed by 130 ℃ for 20h, and then allowed to cool to room temperature naturally to give a brown gel mass. The brown gel mass was then heated in an oven at 200 ℃ for 4h and allowed to cool to room temperature to give a tan powder. And transferring the brownish black powder into an ash furnace, calcining for 1h at 250 ℃, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1h, continuously heating to 500 ℃ and calcining for 12h, and naturally cooling to room temperature to ensure that organic matters in the brown black powder are removed, so that white precursor powder is obtained. Carrying out high-temperature ammonia gas post-treatment on the white precursor powder: placing the white precursor powder in a quartz boat, and moving the quartz boatPutting the mixture into an alumina tube type furnace, treating the mixture for 15h in an ammonia atmosphere at 950 ℃ (the flow rate of the ammonia is controlled to be 500mL/min), and then cooling the mixture to room temperature to obtain LaTiO2N red powder;
2) 0.1mol/L Co (NO) is prepared in advance3)2Aqueous solution and 0.1mol/L (NH)4)3PO4An aqueous solution. 0.2g of prepared LaTiO is taken2Adding the N powder into 60mL of deionized water, and carrying out ultrasonic dispersion for 10 min. Then, 3270. mu.L of the prepared (NH) was added thereto using a pipette gun under stirring4)3PO4Stirring the aqueous solution for 1min, and adding 4908 μ L of the prepared Co (NO)3)2Aqueous solution, ensuring that the molar ratio of Co and P added is 3: 2. Stirring the obtained reaction solution at room temperature for 2H, transferring the reaction solution into a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 6H, then naturally cooling to room temperature, carrying out centrifugal washing on the obtained red precipitate with water and ethanol, and drying to obtain the basic cobalt phosphate nanoneedle composite LTON photocatalyst, which is marked as CoPi-H/LTON-33%, wherein Co in the catalyst is Co3(OH)2(HPO4)2Is LaTiO233% of the mass of N.
Example 2:
1) 0.05mol of citric acid monohydrate, 0.001mol of tetraisopropyl titanate, 0.001mol of lanthanum nitrate hexahydrate and 0.2mol of ethylene glycol are sequentially added into 80mL of methanol and stirred to be dissolved, so that transparent colloid is obtained. The clear colloid was oil-bathed at 60 ℃ for 6h, followed by 120 ℃ for 24h, and then naturally cooled to room temperature to give a brown gel mass. The brown gel mass was then heated in an oven at 200 ℃ for 2h and allowed to cool to room temperature to give a tan powder. And transferring the brownish black powder into an ash furnace, calcining for 1.5h at 250 ℃, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1.5h, continuously heating to 500 ℃ and calcining for 15h, and naturally cooling to room temperature to remove organic matters to obtain white precursor powder. Carrying out high-temperature ammonia gas post-treatment on the white precursor powder: placing white precursor powder in quartz boat, transferring the quartz boat into alumina tube furnace, and treating at 950 deg.C in ammonia gas atmosphereTreating for 16h (controlling the flow rate of ammonia gas to be 300mL/min), and then cooling to room temperature to obtain LaTiO2N red powder;
2) 0.1mol/L Co (NO) is prepared in advance3)2Aqueous solution and 0.1mol/L (NH)4)3PO4An aqueous solution. 0.094g of prepared LaTiO is taken2Adding the N powder into 60mL of deionized water, and carrying out ultrasonic dispersion for 15 min. Then, 3270. mu.L of the prepared (NH) was added thereto using a pipette gun under stirring4)3PO4Stirring the aqueous solution for 2min, and adding 4908 μ L of the prepared Co (NO)3)2Aqueous solution, ensuring that the molar ratio of Co and P added is 3: 2. Stirring the obtained reaction solution at room temperature for 2H, transferring the reaction solution into a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 6H, then naturally cooling to room temperature, carrying out centrifugal washing on the obtained red precipitate with water and ethanol, and drying to obtain the basic cobalt phosphate nanoneedle composite LTON photocatalyst, which is marked as CoPi-H/LTON-70%, wherein Co in the catalyst is Co3(OH)2(HPO4)2Is LaTiO270% of the mass of N.
Example 3:
1) 0.06mol of citric acid monohydrate, 0.005mol of tetraisopropyl titanate, 0.005mol of lanthanum nitrate hexahydrate and 0.24mol of ethylene glycol are sequentially added into 120mL of methanol and stirred to be dissolved, so that transparent colloid is obtained. The clear colloid was oil-bathed at 90 ℃ for 2h, followed by 150 ℃ for 18h, and then naturally cooled to room temperature to give a brown gel mass. The brown gel mass was then heated in an oven at 200 ℃ for 3h and allowed to cool to room temperature to give a tan powder. And transferring the brownish black powder into an ash furnace, calcining for 2h at 250 ℃, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 2h, continuously heating to 500 ℃ and calcining for 18h, and naturally cooling to room temperature to ensure that organic matters in the brown black powder are removed, so that white precursor powder is obtained. Carrying out high-temperature ammonia gas post-treatment on the white precursor powder: placing the white precursor powder in a quartz boat, moving the quartz boat into an alumina tube furnace, treating at 950 deg.C under ammonia atmosphere for 17h (ammonia flow rate is controlled at 400mL/min), and coolingCooling to room temperature to obtain LaTiO2N red powder;
2) 0.1mol/L Co (NO) is prepared in advance3)2Aqueous solution and 0.1mol/L (NH)4)3PO4An aqueous solution. 0.06g of prepared LaTiO is taken2Adding the N powder into 60mL of deionized water, and carrying out ultrasonic dispersion for 5 min. Then 2000. mu.L of the above-prepared (NH) was added thereto using a pipette under stirring4)3PO4Stirring the aqueous solution for 6min, and adding 3000 μ L of the prepared Co (NO)3)2Aqueous solution, ensuring that the molar ratio of Co and P added is 3: 2. Stirring the obtained reaction solution at room temperature for 1H, transferring the reaction solution to a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 4H, then naturally cooling to room temperature, carrying out centrifugal washing on the obtained red precipitate with water and ethanol, and drying to obtain the basic cobalt phosphate nanoneedle composite LTON photocatalyst, which is marked as CoPi-H/LTON-67%, wherein Co in the catalyst is Co3(OH)2(HPO4)2Is LaTiO267% of the mass of N.
Example 4:
1) 0.07mol of citric acid monohydrate, 0.015mol of tetraisopropyl titanate, 0.015mol of lanthanum nitrate hexahydrate and 0.28mol of ethylene glycol are sequentially added into 100mL of methanol and stirred to be dissolved, so that transparent colloid is obtained. The clear colloid was oil-bathed at 80 ℃ for 3h, followed by 140 ℃ for 19h, and then naturally cooled to room temperature to give a brown gel mass. The brown gel mass was then heated in an oven at 200 ℃ for 5h and allowed to cool to room temperature to give a tan powder. And transferring the brownish black powder into an ash furnace, calcining for 1.2h at 250 ℃, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1.2h, continuously heating to 500 ℃ and calcining for 20h, and naturally cooling to room temperature to remove organic matters to obtain white precursor powder. Carrying out high-temperature ammonia gas post-treatment on the white precursor powder: placing the white precursor powder in a quartz boat, moving the quartz boat into an alumina tube furnace, treating for 18h at 950 ℃ in an ammonia atmosphere (the flow rate of ammonia is controlled to be 350mL/min), and then cooling to room temperature to obtain LaTiO2N Red powder；
2) 0.1mol/L Co (NO) is prepared in advance3)2Aqueous solution and 0.1mol/L (NH)4)3PO4An aqueous solution. 0.3g of prepared LaTiO is taken2The N powder was added to 60mL of deionized water and ultrasonically dispersed for 18 min. Then 3000. mu.L of the prepared (NH) was added thereto using a pipette gun under stirring4)3PO4Stirring the aqueous solution for 8min, adding 4500 μ L of the prepared Co (NO)3)2Aqueous solution, ensuring that the molar ratio of Co and P added is 3: 2. Stirring the obtained reaction solution at room temperature for 1.2H, transferring the reaction solution to a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 5H, then naturally cooling to room temperature, centrifugally washing and drying the obtained red precipitate with water and ethanol to obtain the basic cobalt phosphate nanoneedle composite LTON photocatalyst, which is marked as CoPi-H/LTON-20%, wherein Co in the catalyst is Co3(OH)2(HPO4)2Is LaTiO220% of the mass of N.
Example 5:
1) 0.08mol of citric acid monohydrate, 0.012mol of tetraisopropyl titanate, 0.012mol of lanthanum nitrate hexahydrate and 0.32mol of ethylene glycol are sequentially added into 60mL of methanol and stirred for dissolution to obtain transparent colloid. The clear colloid was oil-bathed at 65 ℃ for 5h, followed by 125 ℃ for 22h, and then naturally cooled to room temperature to give a brown gel mass. The brown gel mass was then heated in an oven at 200 ℃ for 6h and allowed to cool to room temperature to give a tan powder. And transferring the brownish black powder into an ash furnace, calcining for 1.8h at 250 ℃, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1.8h, continuously heating to 500 ℃ and calcining for 22h, and naturally cooling to room temperature to remove organic matters to obtain white precursor powder. Carrying out high-temperature ammonia gas post-treatment on the white precursor powder: placing the white precursor powder in a quartz boat, moving the quartz boat into an alumina tube furnace, treating for 19h at 950 ℃ in an ammonia atmosphere (the flow rate of ammonia is controlled to be 450mL/min), and then cooling to room temperature to obtain LaTiO2N red powder;
2) is prepared in advance0.1mol/L Co(NO3)2Aqueous solution and 0.1mol/L (NH)4)3PO4An aqueous solution. 0.606g of prepared LaTiO is taken2Adding the N powder into 60mL of deionized water, and carrying out ultrasonic dispersion for 20 min. Then 4000. mu.L of the prepared (NH) was added thereto using a pipette gun under stirring4)3PO4Stirring the aqueous solution for 10min, and adding 6000 μ L of the prepared Co (NO)3)2Aqueous solution, ensuring that the molar ratio of Co and P added is 3: 2. Stirring the obtained reaction solution at room temperature for 1.5H, transferring the reaction solution to a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 7H, then naturally cooling to room temperature, centrifugally washing and drying the obtained red precipitate with water and ethanol to obtain the basic cobalt phosphate nanoneedle composite LTON photocatalyst, which is marked as CoPi-H/LTON-13%, wherein Co in the catalyst is Co3(OH)2(HPO4)2Is LaTiO213 percent of the mass of N.
Example 6:
1) 0.09mol of citric acid monohydrate, 0.018mol of tetraisopropyl titanate, 0.018mol of lanthanum nitrate hexahydrate and 0.36mol of ethylene glycol are sequentially added into 150mL of methanol and stirred to be dissolved, so that transparent colloid is obtained. The clear colloid was oil-bathed at 75 ℃ for 3.5h, followed by 135 ℃ for 19.5h, and then allowed to cool to room temperature to give a brown gel mass. The brown gel mass was then heated in an oven at 200 ℃ for 4.5h and allowed to cool to room temperature to give a tan powder. And transferring the brownish black powder into an ash furnace, calcining for 1.3h at 250 ℃, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1.3h, continuously heating to 500 ℃ and calcining for 24h, and naturally cooling to room temperature to remove organic matters to obtain white precursor powder. Carrying out high-temperature ammonia gas post-treatment on the white precursor powder: placing the white precursor powder in a quartz boat, moving the quartz boat into an alumina tube furnace, treating for 20h at 950 ℃ in an ammonia atmosphere (the flow rate of ammonia is controlled to be 380mL/min), and cooling to room temperature to obtain LaTiO2N red powder;
2) 0.1mol/L Co (NO) is prepared in advance3)2Aqueous solution and 0.1mol/L (NH)4)3PO4An aqueous solution. 0.606g of prepared LaTiO is taken2Adding the N powder into 60mL of deionized water, and carrying out ultrasonic dispersion for 8 min. Then, 1000. mu.L of the prepared (NH) was added thereto under stirring using a pipette4)3PO4Stirring the aqueous solution for 3min, and adding 1500 μ L of the prepared Co (NO)3)2Aqueous solution, ensuring that the molar ratio of Co and P added is 3: 2. Stirring the obtained reaction solution at room temperature for 1.8H, transferring the reaction solution to a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 8H, then naturally cooling to room temperature, centrifugally washing and drying the obtained red precipitate with water and ethanol to obtain the basic cobalt phosphate nanoneedle composite LTON photocatalyst, which is marked as CoPi-H/LTON-3%, wherein Co in the catalyst is Co3(OH)2(HPO4)2Is LaTiO23% of the mass of N.
Example 7:
1) 0.1mol of citric acid monohydrate, 0.02mol of tetraisopropyl titanate, 0.02mol of lanthanum nitrate hexahydrate and 0.4mol of ethylene glycol are sequentially added into 200mL of methanol and stirred to be dissolved, so that transparent colloid is obtained. The clear colloid was oil-bathed at 85 ℃ for 2.5h, followed by 145 ℃ for 18.5h, and then allowed to cool to room temperature to give a brown gel mass. The brown gel mass was then heated in an oven at 200 ℃ for 3.5h and allowed to cool to room temperature to give a tan powder. And transferring the brownish black powder into an ash furnace, calcining for 1.7h at 250 ℃, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1.7h, continuously heating to 500 ℃ and calcining for 16h, and naturally cooling to room temperature to remove organic matters to obtain white precursor powder. Carrying out high-temperature ammonia gas post-treatment on the white precursor powder: placing the white precursor powder in a quartz boat, moving the quartz boat into an alumina tube furnace, treating for 15h at 950 ℃ in an ammonia atmosphere (the flow rate of ammonia is controlled to be 480mL/min), and then cooling to room temperature to obtain LaTiO2N red powder;
2) 0.1mol/L Co (NO) is prepared in advance3)2Aqueous solution and 0.1mol/L (NH)4)3PO4An aqueous solution. 0.10g of prepared LaTiO is taken2N powder was added to 60mL deionized water and dispersed by sonication for 12 min. Then 2000. mu.L of the above-prepared (NH) was added thereto using a pipette under stirring4)3PO4Stirring the aqueous solution for 5min, and adding 3000 μ L of the prepared Co (NO)3)2Aqueous solution, ensuring that the molar ratio of Co and P added is 3: 2. Stirring the obtained reaction solution at room temperature for 2H, transferring the reaction solution into a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 6.5H, then naturally cooling to room temperature, centrifugally washing and drying the obtained red precipitate with water and ethanol to obtain the basic cobalt phosphate nanoneedle composite LTON photocatalyst, which is marked as CoPi-H/LTON-40%, wherein Co in the catalyst is Co3(OH)2(HPO4)2Is LaTiO2And 40% of the mass of N.
Comparative examples 1 and 2 give LaTiO as a comparison2N and Co3(OH)2(HPO4)2Photocatalysts, examples 1-7, were basic cobalt phosphate nanoneedle composite LTON photocatalysts (i.e., Co) prepared under different conditions3(OH)2(HPO4)2Nano needle compounded LaTiO2N photocatalyst). The following is a description of the drawings, in which the basic cobalt phosphate nanoneedle composite LTON photocatalyst prepared in example 1 has the best photocatalytic oxygen production performance.
FIG. 1 shows the X-ray diffraction patterns of LTON, CoPi-H prepared in comparative examples 1 and 2, and CoPi-H/LTON-33% prepared in example 1. Firstly, the prepared LTON and CoPi-H diffraction peaks are respectively associated with LaTiO2N (JCPDS No.00-048-1230) and Co3(OH)2(HPO4)2The diffraction peaks of (JCPDS No.01-079-2238) coincided, confirming that LaTiO was synthesized2N and Co3(OH)2(HPO4)2And (3) sampling. When it is reacted with Co3(OH)2(HPO4)2After compounding, LaTiO2The characteristic diffraction peak of N is not changed, which indicates that the complex with cobalt phosphate and the hydrothermal treatment on LaTiO2The crystal structure of N has no significant effect. In addition, the X-ray diffraction pattern of the composite sample is other than LaTiO2Besides the characteristic peak of N, other diffraction peaks appear between 25 and 30 degrees, and research shows that the diffraction peaks belong to Co3(OH)2(HPO4)2The characteristic diffraction peak of the LaTiO proves that2N and Co3(OH)2(HPO4)2And (4) successfully compounding.
FIG. 2 is a scanning electron micrograph showing that LTON is composed of irregular bulk agglomerates with porous surfaces caused by structural collapse when N replaces O in the crystal structure during high temperature ammonia gas post-treatment, consistent with literature reports. CoPi-H shows a different morphology from LTON and is formed by agglomeration of micron-sized block-shaped substances with smooth surfaces. When LaTiO is used2N and Co3(OH)2(HPO4)2When compounded, the compounded sample was compared to LaTiO alone2The N morphology changed greatly. As can be seen from the scanning electron micrograph of the composite sample, the appearance of the sample is still mainly porous irregular blocky agglomerates on the surface, only compared with pure LaTiO2The N porous surface is changed, namely, nanoneedles are grown on the surface. Comparing with the scanning electron microscope photo of LTON and combining the X-ray diffraction pattern result, the surface nanoneedle of the composite sample can be inferred to be Co3(OH)2(HPO4)2With pure Co3(OH)2(HPO4)2The micro-morphology of the particles is very different, further illustrating that LaTiO2N and Co3(OH)2(HPO4)2Effective chemical bonding occurs by the recombination.
Fig. 3 is a uv-vis absorption spectrum. As can be seen in FIG. 3, LTON can effectively absorb visible light with an absorption edge around 600nm, consistent with literature reports. In addition, LTON also has a relatively strong absorption in the wavelength range above 600nm, which is due to Ti generated during the synthesis process3+Ion and defect. For the CoPi-H sample, the absorption is strong in the range of 400 to 630nm, and a wide absorption peak is around 682nm, which is formed by the highly-spinning Co in the distorted Co octahedron2+Caused by ionic d-d transitions. And CoPi-H/LTON-33% from the composite sampleThe ultraviolet-visible absorption spectrum shows that the absorption of the composite sample is almost the same relative to LTON, which indicates that LaTiO2N and Co3(OH)2(HPO4)2Composite para LaTiO2The absorption of N has little effect.
FIG. 4 is an infrared spectrum. For the composite sample CoPi-H/LTON-33%, the infrared spectrum shows LaTiO2All characteristic peaks of N indicate complex Co3(OH)2(HPO4)2Para LaTiO2The crystal structure of N has no obvious influence and is consistent with the X-ray diffraction result. In addition, the spectrum shows 3498, 1299, 1096 and 956cm-1The characteristic peaks are compared with the spectrogram of CoPi-H, and the characteristic peaks belong to Co3(OH)2(HPO4)2Further describes LaTiO2N and Co3(OH)2(HPO4)2The composition of (A) and (B) is consistent with the results of X-ray diffraction and a scanning electron microscope.
Fig. 5 is a raman spectrum. From the Raman spectrum, LTON was found at 330 and 535cm-1Two obvious characteristic peaks are located, and the two characteristic peaks respectively correspond to La-O vibration and Ti-O vibration. The Raman spectrum of CoPi-H/LTON-33% is not obviously different from that of LTON, which shows that the compounding pair LaTiO2The microstructure of N has no significant effect.
FIG. 6 is an X-ray photoelectron spectrum. First, for LTON, the Ti 2p spectrum has two peaks at 457.7 and 463.4eV, which correspond to Ti 4+2p of3/2And 2p1/2Orbitals with small amounts of Ti observed3+A signal is present. While for the CoPi-H/LTON-33% composite sample, 2p of Ti3/2And 2p1/2The orbitals are respectively 458.3 and 464.0eV, and are also Ti4+But Ti relative to LTON 4+2p of3/2And 2p1/2The rail moves slightly toward the high binding energy, which may be due to Co3(OH)2(HPO4)2Caused by compounding, further illustrate LaTiO2N and Co3(OH)2(HPO4)2Effective bonding is performed. No Co signal was observed in the Co2p spectrum of LTON, so to speakThere is no Co present in the clear LTON. As for CoPi-H, according to analysis, the peaks at 782.0 and 798.0eV correspond to Co 2+2p of3/2And 2p1/2Orbitals, while the broad peaks at 785.8 and 803.2eV correspond to Co2+2p3/2 and 2p1/2The satellite peak of (a). In addition, no observation was made about Co3+And other valence Co peaks, indicating the presence of Co alone in the CoPi-H2+. In the CoPi-H/LTON-33% sample, Co 2+2p of3/2And 2p1/2Orbitals 781.4 and 797.1eV, respectively, and the corresponding satellite peaks 785.6 and 802.9eV, slightly shifted toward lower binding energies compared to the Co2P orbit of pure CoPi-P, indicating that the recombination altered Co2+Further indicates the chemical environment of LaTiO2N and Co3(OH)2(HPO4)2The effective composition of (1).
FIG. 7 shows the visible light photocatalytic oxygen production profiles for LTON, CoPi-H/LTON-33% and CoPi-H. Firstly, pure LTON has a certain oxygen generating activity, and the oxygen generating rate is about 0.43 mmol.h-1·gcat -1LaTiO synthesized by polymerization and complexation methods reported in the literature2The oxygen generating activity of N is consistent, while the oxygen generating activity of CoPi-H is about 0.23 mmol.h-1·gcat -1. When LaTiO is used2N and Co3(OH)2(HPO4)2After the compounding is carried out, compared with pure LTON, the oxygen generating activity is greatly improved, wherein the oxygen generating activity of a compounded sample CoPi-H/LTON-33 percent reaches 1.49 mmol.h-1·gcat -12.5 times that of pure LTON. The above results illustrate LaTiO2N and Co3(OH)2(HPO4)2Effectively improves LaTiO by compounding2Photocatalytic oxygen generation performance of N.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims (10)
1. A preparation method of basic cobalt phosphate nanoneedle composite LTON photocatalyst is characterized by comprising the following specific steps:
1) preparation of LaTiO2N powder
Adding A mol of citric acid monohydrate, B mol of tetraisopropyl titanate, C mol of lanthanum nitrate hexahydrate and D mol of ethylene glycol into EmL methanol, and stirring and dissolving to obtain a transparent colloid, wherein A: B: E ═ 0.04-0.1, (0.001-0.02): 50-200, B: C ═ 1:1, and A: D ═ 1: 4; carrying out oil bath on the transparent colloid at the temperature of 60-90 ℃ for 2-6 h, then carrying out oil bath at the temperature of 120-150 ℃ for 18-24 h, and then naturally cooling to room temperature to obtain a gel substance; drying the gel substance into powder, and transferring the powder into an ash furnace for calcining to obtain precursor powder; finally, ammonia gas post-treatment is carried out on the precursor powder to obtain LaTiO2N powder;
2) in LaTiO2In-situ hydrothermal growth of Co on N powder3(OH)2(HPO4)2Nano needle
F g LaTiO2Adding N powder into deionized water, ultrasonically dispersing uniformly, and adding (NH) with P content of G mmol under stirring4)3PO4Mixing the aqueous solution, adding Co (NO) with H mmol of Co3)2And (3) obtaining a reaction solution by using an aqueous solution, wherein F is G (0.06-0.606) and G is 0.1-0.4, H is 2:3, continuously stirring the reaction solution at room temperature for 1-2H, transferring the reaction solution to a hydrothermal kettle, carrying out heat preservation reaction at 200 ℃ for 4-8H, naturally cooling to room temperature, washing and drying the precipitate obtained by the reaction, and thus obtaining the basic cobalt phosphate nanoneedle composite LTON photocatalyst.
2. The preparation method of the basic cobalt phosphate nanoneedle composite LTON photocatalyst according to claim 1, characterized in that: the drying in the step 1) is to heat the gel substance in an oven at 200 ℃ for 2-6 h, and then naturally cool the gel substance to room temperature to obtain powder.
3. The preparation method of the basic cobalt phosphate nanoneedle composite LTON photocatalyst according to claim 1, characterized in that: the calcination in the ash furnace in the step 1) is specifically as follows: transferring the powder to an ash furnace, calcining at 250 ℃ for 1-2 h, naturally cooling to room temperature, heating to 350 ℃ in the ash furnace, calcining for 1-2 h, then continuously heating to 500 ℃, calcining for 12-24 h, and finally naturally cooling to room temperature to obtain precursor powder.
4. The preparation method of the basic cobalt phosphate nanoneedle composite LTON photocatalyst according to claim 1, characterized in that: the ammonia gas post-treatment of the precursor powder in the step 1) specifically comprises the following steps: placing the precursor powder in a quartz boat, moving the quartz boat into an alumina tube furnace, treating for 15-20 h at 950 ℃ in an ammonia gas atmosphere with the ammonia gas flow rate of 300-500 mL/min, and cooling to room temperature after treatment to obtain LaTiO2And (4) N powder.
5. The preparation method of the basic cobalt phosphate nanoneedle composite LTON photocatalyst according to claim 1, characterized in that: in the step 2), every 0.06-0.606 g of LaTiO is added2And adding the N powder into 60mL of deionized water, wherein the time required for uniform ultrasonic dispersion is 5-20 min.
6. The preparation method of the basic cobalt phosphate nanoneedle composite LTON photocatalyst according to claim 1, characterized in that: adding (NH) in the step 2)4)3PO4The time required for stirring the aqueous solution uniformly is 1-10 min.
7. The preparation method of the basic cobalt phosphate nanoneedle composite LTON photocatalyst according to claim 1, characterized in that: (NH) in said step 2)4)3PO4Aqueous solution and Co (NO)3)2The concentration of the aqueous solution was 0.1mol/L, (NH)4)3PO4The addition amount of the aqueous solution is 1000-4000 mu L, and Co (NO)3)2The addition amount of the aqueous solution is 1500-6000 mu L.
8. According to claim 1-7, the basic cobalt phosphate nanoneedle composite LTON photocatalyst prepared by the preparation method of the basic cobalt phosphate nanoneedle composite LTON photocatalyst is characterized in that: the basic cobalt phosphate nanoneedle composite LTON photocatalyst is an irregular blocky agglomerate LaTiO with porous surface2N surface grows Co3(OH)2(HPO4)2The basic cobalt phosphate nanoneedle is compounded with Co in LTON photocatalyst3(OH)2(HPO4)2With LaTiO2The mass percentage of N is x, x is more than 0 and less than or equal to 70 percent.
9. The basic cobalt phosphate nanoneedle composite LTON photocatalyst of claim 8, which is characterized in that: the oxygen production activity of the basic cobalt phosphate nanoneedle composite LTON photocatalyst in oxygen production by photocatalytic decomposition of water under visible light is 1.02-1.49 mmol.h-1·gcat -1。
10. The use of the basic cobalt phosphate nanoneedle composite LTON photocatalyst of claim 8 or 9 in photocatalytic decomposition of water under visible light to produce oxygen.
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| Title |
|---|
| "Hydrothermal growth of Co3(OH)2(HPO4)2 nano-needles on LaTiO2N for enhanced water oxidation under visible-light irradiation";Yazhou Zhang et al.;《Applied Catalysis B: Environmental》;20180320;第232卷;第268-274页 * |
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