A synthesis method of Zr2ON2 material and its application

Abstract

The present invention discloses a method for synthesizing a Zr2ON2 material and its application. The method comprises the following steps: grinding and mixing zirconium oxide and an active metal hydride to obtain a mixture; subjecting the mixture to a nitridation reaction at 700°C to 850°C in an ammonia atmosphere for 0.3 to 30 hours, followed by washing and drying to obtain the Zr2ON2 material. The present invention uses an active metal hydride as a nitridation aid for co-nitridation with ZrO2. The Zr2ON2 material can be completely nitrided and transformed into a Zr2ON2 material at a relatively low temperature and in a relatively short time. The material has high crystallinity and a low defect state density, and exhibits excellent photocatalytic activity in applications such as photocatalytic dye degradation, photocatalytic water decomposition to produce hydrogen, or photocatalytic water decomposition to produce oxygen.

Description

Technical Field

[0001] The present invention relates to the technical field of zirconium-based oxynitride material synthesis, and more specifically, to a synthesis method of a Zr2ON2 material and applications thereof. Background Art

[0002] Based on d 0 Nitride materials of electronic structure metals (mainly including Ta, Ti, Zr, Nb) have attracted widespread attention due to their novel optical, electrical, magnetic and photocatalytic properties. This type of nitrogen oxide has a lower theoretical band gap value (1.5eV~2.5eV) than oxides, and has the potential to catalyze the splitting of water in the visible light range (wavelength 400nm~800nm); at the same time, it has the advantages of both metal oxides and nitrides, has good chemical stability and thermal stability, is very stable in water and strong acids and bases, and begins to decompose above 500°C in air and above 800°C in inert atmosphere. Among them, Ta-based metal nitride semiconductor materials have been studied more, and the reason is that Ta 5+ The valence state is highly stable and is reduced to a lower valence Ta 4+ and Ta 3+ Therefore, the framework structure of Ta-based nitride synthesized by nitridation under high temperature in a reducing ammonia flow is the most complete and the total defect state density is low, so it often exhibits very excellent photocatalytic performance. 5+ 、Ti 4 + 、Zr 4+ 、Nb 5+ These four d 0 Among the metal ions with electronic structure, Zr 4+ It also has very high valence stability, that is, the valence change characteristics of tetravalent Zr are relatively weak, so theoretically it is possible to obtain metal nitride oxide semiconductor materials with low defect state density based on Zr.

[0003] Zr2ON2 materials absorb visible light up to 500 nm, exhibiting a vibrant yellow-green color. They hold broad application prospects in visible-light-excited photocatalysis, semiconductor optics, and coating materials. However, methods for synthesizing Zr-based oxynitride materials are limited. This is primarily due to the fact that the nitridation precursor used is ZrO2, whose Zr-O bond has a large ionic component and high bond energy, making it difficult to break the Zr-O bond and form the Zr-N bond under conventional high-temperature conditions. For example, the synthesis of ZrN requires temperatures of 1500°C and nitridation times of several dozen hours. Synthesis of Zr2ON2 also requires temperatures exceeding 1000°C and nitridation times exceeding 40 hours (Applied Catalysis A: General 324 (2007) 77–82). Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a synthesis method and application of Zr2ON2 material, which uses active metal hydride as a nitriding aid and co-nitrides with ZrO2. It can be completely nitrided and transformed into Zr2ON2 material at a lower temperature and in a shorter time. The material has high crystallinity and low defect state density, and its application in photocatalytic dye degradation, photocatalytic water decomposition hydrogen production reaction or photocatalytic water decomposition oxygen production reaction achieves excellent photocatalytic activity.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A method for synthesizing a Zr2ON2 material comprises the following steps:

[0007] S1. Grind and mix zirconium oxide and an active metal hydride to obtain a mixture.

[0008] S2. In an ammonia atmosphere, the mixture is subjected to a nitridation reaction at 700° C. to 850° C. for 0.3 h to 30 h, and then washed and dried to obtain the Zr2ON2 material.

[0009] Optionally, the temperature of the nitridation reaction is 700° C. to 800° C.; and the time of the nitridation reaction is 2 h to 15 h.

[0010] Optionally, the mass ratio of the active metal hydride to the zirconium oxide is 0.1 to 10:1.

[0011] Optionally, the active metal hydride includes one or more of MgH2, CaH2, LiH and AlH3.

[0012] Optionally, the washing specifically includes: washing the nitrided product with one or more of dilute hydrochloric acid, dilute nitric acid, and dilute sulfuric acid with a concentration of 1 mmol / L to 1 mol / L for 1 minute to 1 hour.

[0013] Optionally, the tubular furnace used in the nitridation reaction includes a vertical tubular furnace or a horizontal tubular furnace, and the container used in the nitridation reaction includes a quartz hanging basket or a corundum porcelain boat.

[0014] Optionally, a mixture of active metal hydride and zirconium oxide is placed in a quartz hanging basket, which is then placed in a vertical tube furnace. After purging with NH3 gas flow, the temperature is raised to the nitriding temperature at a heating rate of 1°C / min to 10°C / min for reaction.

[0015] Optionally, a mixture of active metal hydride and zirconium oxide is placed in the center of a corundum boat, which is then placed in a horizontal tube furnace. After purging with NH3 gas flow, the temperature is raised to the nitriding temperature at a heating rate of 1°C / min to 10°C / min for reaction.

[0016] The present invention also discloses a Zr2ON2 material obtained by the above synthesis method.

[0017] The present invention also discloses a Zr2ON2 material obtained by the above-mentioned synthesis method, or the application of the above-mentioned Zr2ON2 material in photocatalytic dye degradation, photocatalytic water decomposition hydrogen production reaction or photocatalytic water decomposition oxygen production reaction.

[0018] Optionally, when the Zr2ON2 material is used for photocatalytic dye degradation, the Zr2ON2 material is dispersed in a dye aqueous solution and illuminated with LED light under oxygenated conditions to eliminate dye molecules in the dye aqueous solution through photooxidation. The Zr2ON2 material can be a Zr2ON2 material without a co-catalyst deposited thereon or a Zr2ON2 material with Pt deposited thereon.

[0019] Optionally, when the Zr2ON2 material is used in a photocatalytic water splitting reaction to produce hydrogen, the Zr2ON2 material is used as a photocatalyst, formic acid is used as a hole sacrificial reagent, H2O is used as an electron acceptor, and La2O3 is used as a pH buffer. H2O is reduced by light to produce hydrogen. The Zr2ON2 material may be a Pt-deposited Zr2ON2 material.

[0020] Optionally, when the Zr2ON2 material is used in a photocatalytic water splitting oxygen production reaction, the Zr2ON2 material is used as a photocatalyst, AgNO3 is used as an electron sacrificial reagent, and La2O3 is used as a pH buffer, and H2O is oxidized by light to produce oxygen. The Zr2ON2 material may be a Zr2ON2 material with deposited cobalt oxide.

[0021] It should be noted that the specific deposition method of the Zr2ON2 material for depositing Pt and the Zr2ON2 material for depositing cobalt oxide is an existing technology in the relevant technical field. Technical personnel in the relevant technical field have the ability to obtain this technology and apply it to the preparation of Zr2ON2 material for depositing Pt and Zr2ON2 material for depositing cobalt oxide. This is an essential skill for technical personnel in the relevant technical field, so the present invention will no longer describe it in detail.

[0022] The implementation of the present invention will have the following beneficial effects:

[0023] The present invention develops a new nitriding process, which adopts the hydride of active metal as a nitriding auxiliary agent, and then mixes it with ZrO2 for co-nitriding, so as to achieve complete nitridation and phase conversion to Zr2ON2 material at a lower temperature in a shorter time, which is faster and more energy-saving. The synthesized Zr2ON2 nitrogen oxide has a uniform bright color, high crystallinity and low defect state density, which solves the problems of high synthesis temperature and long nitriding time of existing zirconium-based nitrogen oxide Zr2ON2. It is applied to photocatalytic dye degradation, photocatalytic water decomposition hydrogen production reaction or photocatalytic water decomposition oxygen production reaction, and achieves excellent photocatalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 XRD signal, UV-visible absorption spectrum, scanning electron microscope image and sample photo of the Zr2ON2 nitrogen oxide prepared in Example 1 of the present invention.

[0025] Figure 2 XRD signal and scanning electron microscope image of Zr2ON2 nitrogen oxide prepared in Example 2 of the present invention.

[0026] Figure 3 These are the catalytic activity test diagrams for photodegradation of dye molecules, visible light reduction of water to produce hydrogen, and visible light reduction of water to produce oxygen corresponding to the application examples. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0028] Example 1

[0029] (1) Mechanically grind and mix 0.15 g of CaH2 and 0.15 g of ZrO2 powder.

[0030] (2) Take the above mixture and place it in the center of the corundum porcelain boat. Place the corundum porcelain boat in the center of the quartz tube of the horizontal tube furnace. Seal the quartz tube and connect it to the NH3 pipeline.

[0031] (3) Turn on NH3 at a flow rate of 200 ml / min, and after purging at room temperature, increase the temperature to 800°C at a rate of 5°C / min, and nitride at a constant temperature of 800°C for 5 h. After nitridation is completed, cool it down naturally. When it drops to 200°C, switch to nitrogen flow for purging, and take out the powder after it drops to room temperature.

[0032] (4) The obtained powder was dispersed in a certain amount of dilute hydrochloric acid with a concentration of 0.1 mol / L, stirred for 1 hour, and then the powder sample was centrifuged, washed with water, and dried to obtain pure Zr2ON2 powder.

[0033] Example 2

[0034] (1) Mechanically grind and mix 0.05 g of CaH2 and 0.5 g of ZrO2 powder.

[0035] (2) Take the above mixture and place it in the center of the corundum porcelain boat. Place the corundum porcelain boat in the center of the quartz tube of the horizontal tube furnace. Seal the quartz tube and connect it to the NH3 pipeline.

[0036] (3) Turn on NH3 at a flow rate of 300 ml / min, and after purging at room temperature, increase the temperature to 750°C at a rate of 5°C / min. Nitridize at a constant temperature of 750°C for 15 h. After nitridation is completed, cool naturally. When it drops to 200°C, switch to nitrogen flow for purging. After cooling to room temperature, take out the powder.

[0037] (4) The obtained powder was dispersed in a certain amount of dilute hydrochloric acid with a concentration of 0.1 mol / L, stirred for 1 hour, and then the powder sample was centrifuged, washed with water, and dried to obtain pure Zr2ON2 powder.

[0038] Example 3

[0039] (1) Mechanically grind and mix 0.3 g MgH2 and 0.1 g ZrO2 powders;

[0040] (2) Place the mixture in a quartz hanging basket, place the quartz hanging basket on the air flow baffle in the center of the quartz tube, seal the quartz tube and connect the NH3 pipeline;

[0041] (3) NH3 was turned on at a flow rate of 100 ml / min and purged at room temperature for 30 min. The temperature was then raised to 750°C at a rate of 2°C / min and nitrided at a constant temperature of 750°C for 4 h. After nitridation was completed, the temperature was naturally cooled to room temperature and then taken out.

[0042] (4) The obtained powder was dispersed in a certain amount of nitric acid with a concentration of 0.01 mol / L, stirred for 10 min, centrifuged and separated the powder sample, washed with water, and then dried to obtain a pure phase Zr2ON2 powder material.

[0043] Example 4

[0044] (1) Mechanically grind and mix 0.1 g LiH and 0.3 g ZrO2 powders;

[0045] (2) Take the above mixture and place it in the center of a corundum boat. Place the corundum boat in the center of a quartz tube in a horizontal tube furnace. Seal the quartz tube and connect it to the NH3 pipeline.

[0046] (3) Turn on NH3 at a flow rate of 150 ml / min, purge at room temperature, then heat up to 700°C at a rate of 2°C / min, and nitride at 700°C for 2 h. After nitridation is completed, cool naturally. When the temperature drops to 200°C, switch to nitrogen flow for purging. After cooling to room temperature, take out the powder;

[0047] (4) The obtained powder was dispersed in a certain amount of dilute sulfuric acid with a concentration of 1 mmol / L, stirred for 5 minutes, and then the powder sample was centrifuged, washed with water, and dried to obtain pure Zr2ON2 powder.

[0048] Example 5

[0049] (1) Mechanically grind and mix 0.2 g AlH3 and 0.5 g ZrO2 powders;

[0050] (2) Place the mixture in a quartz hanging basket, place the quartz hanging basket on the air flow baffle in the center of the quartz tube, seal the quartz tube and connect the NH3 pipeline;

[0051] (3) NH3 was turned on at a flow rate of 100 ml / min and purged at room temperature for 30 min. The temperature was then raised to 750°C at a rate of 2°C / min and nitrided at a constant temperature of 750°C for 4 h. After nitridation was completed, the temperature was naturally cooled to room temperature and then taken out.

[0052] (4) The obtained powder was dispersed in a certain amount of nitric acid with a concentration of 0.01 mol / L, stirred for 10 min, centrifuged and separated the powder sample, washed with water, and then dried to obtain a pure phase Zr2ON2 powder material.

[0053] Example 6

[0054] (1) Mechanically grind and mix 0.4 g of CaH2 and 0.04 g of ZrO2 powder;

[0055] (2) Take the above mixture and place it in the center of a corundum boat. Place the corundum boat in the center of a quartz tube in a horizontal tube furnace. Seal the quartz tube and connect it to the NH3 pipeline.

[0056] (3) Turn on NH3 at a flow rate of 200 ml / min, purge at room temperature, then heat up to 700°C at a rate of 10°C / min, and nitride at a constant temperature of 700°C for 2 h. After nitridation is completed, cool naturally. When the temperature drops to 200°C, switch to nitrogen flow for purging. After cooling to room temperature, take out the powder;

[0057] (4) The obtained powder was dispersed in a certain amount of dilute nitric acid with a concentration of 0.01 mol / L, stirred for 30 min, and then the powder sample was centrifuged, washed with water, and dried to obtain pure Zr2ON2 powder.

[0058] Example 7

[0059] (1) Mechanically grind and mix 0.04 g of MgH2 and 0.4 g of ZrO2 powders;

[0060] (2) Place the mixture in a quartz hanging basket, place the quartz hanging basket on the air flow baffle in the center of the quartz tube, seal the quartz tube and connect the NH3 pipeline;

[0061] (3) Start NH3 at a flow rate of 100 ml / min and purge at room temperature for 30 min. Then, heat it to 800 °C at a rate of 10 °C / min and nitride it at a constant temperature of 800 °C for 10 h. After nitridation is completed, cool it to room temperature and take it out.

[0062] (4) The obtained powder was dispersed in a certain amount of dilute sulfuric acid with a concentration of 0.01 mol / L, stirred for 10 min, centrifuged and separated the powder sample, washed with water, and then dried to obtain a pure phase Zr2ON2 powder material.

[0063] Application Example 1

[0064] 200 mg of the newly prepared Zr2ON2 according to Example 3 was dispersed in an H2PtCl6 solution containing 2 mg of Pt. The mixture was then heated in a water bath to 80°C with uniform stirring until dry. The Pt-loaded Zr2ON2 photocatalyst was then reduced using an H2 / Ar gas mixture containing 5% H2. 50 mg of the Pt-loaded composite catalyst was then dispersed in a 10 μmol / L Rhodamine B solution. The reaction vessel was stirred in the dark for 20 minutes, with the equilibrium concentration as the initial concentration. The reaction vessel was then irradiated with a 420 nm xenon lamp (15 A current). The remaining methyl orange concentration was measured at 20-minute intervals using a UV-visible absorption spectrometer (UV-2600). The photodegradation efficiency of the Zr2ON2 on the dye molecule methyl orange was determined by analyzing the changes in the methyl orange concentration.

[0065] Application Example 2

[0066] The photocatalytic hydrogen production reaction test was carried out in a top-illuminated reaction tank with a vacuum system and a water cooling system. 150 mg of the composite photocatalyst Pt / Zr2ON2 prepared in Example 1, Example 2, and Example 6 were respectively added to a mixture of 120 ml of deionized water and 30 ml of formic acid, and then 150 mg of La2O3 was added as a buffer. After vacuuming, a circulating water cooling system was used to maintain the reaction tank at 15°C. A 300 W xenon lamp was used as the light source, and a filter was added to irradiate visible light (λ≥420 nm) to test its hydrogen production activity.

[0067] Application Example 3

[0068] The photocatalytic oxygen production test device is the same as above. Take 300 mg of Zr2ON2 prepared in Example 1, Example 2, and Example 6 and disperse it in a Co(NO3)3 solution containing 3 mg of Co. Maintain uniform stirring and heat it in a water bath to 80°C until it is dry. Use ammonia flow to reduce the nitrogen oxides supported on Co. Then place the reduced photocatalyst in a muffle furnace at 150°C for oxidation to obtain the supported oxidation aid CoO xA composite photocatalyst was prepared by adding 150 mg of the composite photocatalyst to 150 ml of deionized water and 0.6 g of AgNO₃ as a sacrificial agent. 150 mg of La₂O₃ was then added as a buffer. After evacuation, the reaction vessel was maintained at 15°C using a circulating water cooling system. A 300 W xenon lamp was used as the light source, and visible light (λ ≥ 420 nm) was irradiated through a filter to test its oxygen production activity.

[0069] The above test results are as follows Figure 1-Figure 3 As shown, the details are as follows:

[0070] Figure 1 (a) is the XRD diffraction pattern of the Zr2ON2 sample prepared in Example 1. Its XRD diffraction peaks completely correspond to the standard card PDF#89-8344 of Zr2ON2, proving the effective synthesis of pure phase structure Zr2ON2. Figure 1 (b) is the UV-visible absorption spectrum of the Zr2ON2 sample prepared in Example 1, which can absorb visible light up to 500nm. Figure 1 (c) is a scanning electron microscope image of the Zr2ON2 sample prepared in Example 1. The sample has a stacked structure of nano-bulks, and the size of its single nanoparticles is about 100 nm. Figure 1 (d) is a physical picture of the Zr2ON2 sample prepared in Example 1, which is a bright yellow powder.

[0071] Figure 2 (a) is the XRD diffraction pattern of the Zr2ON2 sample prepared in Example 2. Its XRD diffraction peaks completely correspond to the standard card PDF#89-8344 of Zr2ON2, proving the effective synthesis of pure phase Zr2ON2. Figure 2 (b) and (c) are scanning electron microscope images of the Zr2ON2 sample prepared in Example 2 (b: magnification: 50,000; c: magnification: 240,000). The sample has a stacked structure of nano-bulks, and the size of its single nanoparticles is about 80 nm.

[0072] Figure 3 (a) is the photocatalytic activity of the Zr2ON2 sample prepared in Example 3 for the degradation of dye molecules. Figure 3 (c) Application of the prepared Pt / Zr2ON2 in photocatalytic water splitting to produce hydrogen (sample a is 1%-Pt / Zr2ON2 (Example 1); sample b is 1%-Pt / Zr2ON2 (Example 2); sample c is 1%-Pt / Zr2ON2 (Example 6)); Figure 3 (d) The prepared Pt / Zr2ON2 was applied to photocatalytic water decomposition and oxygen production (sample a was 2%-CoO x / Zr2ON2 (Example 1); Sample b is 2%-CoO x / Zr2ON2 (Example 2); Sample c is 2%-CoO x / Zr2ON2 (Example 6)), it can be seen that the Zr2ON2 material synthesized by the novel nitridation process of the present invention has excellent photocatalytic activity when applied to photocatalytic dye degradation, photocatalytic water decomposition to produce hydrogen reaction or photocatalytic water decomposition to produce oxygen reaction.

[0073] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for synthesizing Zr2ON2 material, characterized in that: The following steps are involved: Grinding and mixing zirconium oxide and a hydride of an active metal to obtain a mixture; In an ammonia atmosphere, the mixture is subjected to a nitridation reaction at 700° C. to 850° C. for 0.3 h to 30 h, and then washed and dried to obtain the Zr2ON2 material.

2. The method for synthesizing the Zr2ON2 material according to claim 1, characterized in that: The temperature of the nitriding reaction is 700°C to 800°C; The nitridation reaction time is 2 hours to 15 hours.

3. The method for synthesizing the Zr2ON2 material according to claim 1, characterized in that: The mass ratio of the active metal hydride to the zirconium oxide is (0.1-10):

1.

4. The method for synthesizing the Zr2ON2 material according to claim 1, wherein: The active metal hydride includes one or more of MgH2, CaH2, LiH and AlH3.

5. The method for synthesizing the Zr2ON2 material according to claim 1, wherein: The heating rate of the nitriding reaction is 1°C / min to 10°C / min.

6. The method for synthesizing the Zr2ON2 material according to claim 1, characterized in that: The washing specifically includes: washing the nitrided product with one or more of dilute hydrochloric acid, dilute nitric acid, and dilute sulfuric acid with a concentration of 1 mmol / L to 1 mol / L for 1 minute to 1 hour.

7. The method for synthesizing the Zr2ON2 material according to claim 1, characterized in that: The tubular furnace used in the nitriding reaction includes a vertical tubular furnace or a horizontal tubular furnace, and the container used in the nitriding reaction includes a quartz hanging basket or a corundum porcelain boat.

8. Use of the Zr2ON2 material obtained by the synthesis method according to any one of claims 1 to 7 in photocatalytic dye degradation, photocatalytic water decomposition to produce hydrogen, or photocatalytic water decomposition to produce oxygen.

9. The use according to claim 8, characterized in that When the Zr2ON2 material is used for photocatalytic dye degradation, the Zr2ON2 material is dispersed in a dye aqueous solution, and irradiated with LED light under oxygenated conditions to eliminate the dye molecules in the dye aqueous solution by photooxidation; When the Zr2ON2 material is applied to the photocatalytic water decomposition hydrogen production reaction, the Zr2ON2 material is used as a photocatalyst, formic acid is used as a hole sacrificial reagent, H2O is used as an electron acceptor, and La2O3 is used as a pH buffer, and H2O is reduced by light to produce hydrogen; When the Zr2ON2 material is applied to the photocatalytic water decomposition oxygen production reaction, the Zr2ON2 material is used as a photocatalyst, AgNO3 is used as an electron sacrificial reagent, and La2O3 is used as a pH buffer, and H2O is oxidized by light to produce oxygen.

Images