A kind of Ag atom doped into MoS 2-x Atomic Layer@TiO 2-y Nano photocatalyst and preparation method thereof

Abstract

The present invention discloses a preparation method of an Ag atom-doped MoS 2‑x atomic layer @TiO 2‑y nano-photocatalyst, which relates to the field of photocatalysis technology. The Ag atom-doped MoS 2‑x atomic layer @TiO 2‑y nano-photocatalyst in the present invention is prepared by doping Ag atoms into a MoS 2‑x atomic layer @TiO 2‑y nanoarray photocathode. The TiO 2‑y nano-taper array with O defects is prepared by a solvothermal method, and then the preparation of the Ag atom-doped MoS 2‑x atomic layer @TiO 2‑y nano-photocatalyst is carried out by a doping method, in which Ag atoms are doped into the MoS 2‑x atomic layer @TiO 2‑y nanoarray photocathode. The construction of an interfacial heterojunction between TiO 2‑y and MoS 2‑x -Ag extends the response wavelength region of titanium dioxide to the visible light and even the near-infrared region, improves the separation and transfer efficiency of photo-generated electrons and holes, and improves the degradation efficiency and degradation stability of metronidazole.

Description

Technical Field

[0001] The present invention relates to the field of photocatalysis technology, and specifically to a method for doping Ag atoms into MoS2-x atomic layer@TiO 2-y Nano photocatalyst and preparation method thereof. Background Art

[0002] Semiconductor photocatalytic oxidation is a new technology that can decompose organic matter into carbon dioxide and water at room temperature and pressure without causing secondary pollution. It has attracted great attention from researchers around the world. Studies have found that semiconductor photocatalysis can effectively degrade various organic pollutants in water and air, such as halogenated hydrocarbons, nitroaromatic hydrocarbons, phenols, organic pigments, pesticides, surfactants, etc.; it can also convert cyanide, nitrite, thiocyanate, etc. into non-toxic or low-toxic compounds; it can also be used in antibacterial, deodorizing, air purification, self-cleaning materials and other fields. The semiconductor photocatalysts that have been studied so far mainly include metal oxides and sulfides, among which titanium dioxide has the characteristics of good chemical stability, safety and non-toxicity, and low cost, and has been widely studied and applied in the direction of photocatalytic oxidation.

[0003] However, there are still some technical problems with supported photocatalysts. When non-catalytic materials such as adhesives are used, the amount of titanium dioxide on the surface will be affected during the loading and sintering process, thereby affecting the catalytic activity. When titanium dioxide is loaded on carriers such as ceramics, high-temperature calcination is usually used to increase the firmness of the titanium dioxide loading, but titanium dioxide is easily sintered and forms a non-photocatalytically active crystalline phase, thereby affecting the catalytic activity. Third, when titanium dioxide is loaded on carriers such as ceramics, it is also prone to uneven distribution, which further affects its catalytic activity and stability. Therefore, the present invention studies and prepares a photocatalyst that can effectively disinfect microorganisms in the air under ultraviolet / visible light irradiation. Ag atoms are doped into MoS 2-x Atomic Layer@TiO 2-y Nano-photocatalyst. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a Ag atom-doped MoS with high separation and transfer efficiency of photogenerated electrons and holes. 2-x Atomic Layer@TiO 2-y Preparation method of nano-photocatalyst.

[0005] A technical solution proposed by the present invention to solve the above technical problems is: a Ag atom is doped into MoS 2-x Atomic Layer@TiO 2-y The preparation method of nano photocatalyst comprises the following specific steps:

[0006] S1. Place the pretreated titanium sheet in a tube furnace, heat it to 500-550℃ and anneal it for 50-70min under nitrogen protection, and use it as an anode after cooling to room temperature. Use 5-10% formic acid solution as electrolyte at 5mA / cm 2 The cathode was reduced for 5-8 min under constant current conditions, washed with deionized water and ethanol for 3-5 times, and dried in a vacuum oven at 60 °C for 50-70 min to obtain O-deficient TiO 2-y Nanocone arrays;

[0007] S2. Mix ammonium molybdate tetrahydrate, thiourea and deionized water and stir evenly, add silver nitrate 0.3 to 0.5 times the mass of ammonium molybdate tetrahydrate, stir at 600 to 800 rpm for 13 to 17 minutes, transfer to the inner tank of a polytetrafluoroethylene hydrothermal reactor, and heat the TiO 2-y The nanocone array was immersed in water for solvothermal reaction, and then washed with deionized water and ethanol for 3 to 5 times, and dried in a vacuum oven at 60 °C for 25 to 35 min to obtain Ag atoms doped in MoS 2-x Atomic Layer@TiO 2-y Nano-photocatalyst.

[0008] Preferably, in the above step S1., the process of pretreating the titanium sheet is as follows: adding isopropyl titanate in an amount of 0.16 to 0.34 times the volume of acetylacetone to acetylacetone, stirring and mixing at 600 to 800 rpm for 18 to 22 minutes, then adding a 0.07 to 0.08 mol / L aqueous solution of disodium ethylenediaminetetraacetate in an amount of 10 to 16 times the volume of acetylacetone, continuing to stir for 30 to 40 minutes, transferring to a polytetrafluoroethylene hydrothermal reactor liner, vertically immersing the washed titanium sheet in the reactor, heating to 195 to 205° C., reacting for 13 to 15 hours, taking out and washing with deionized water and ethanol for 6 to 8 times, and drying.

[0009] Preferably, the process of cleaning the titanium sheet is: sequentially cleaning the titanium sheet with deionized water, 1 mol / L hydrochloric acid, acetone and ethanol at 40-60 kHz ultrasonic cleaning for 10-15 min, and drying at 60-70°C.

[0010] Preferably, in the above step S1., the nitrogen flow rate is 60-80 ml / min, and the heating rate is 2-3° C. / min.

[0011] Preferably, in the above step S1., the temperature of the electrolyte is 8-12° C., and the distance between the electrode plates is 1.5 cm.

[0012] Preferably, in the above step S2., the mass ratio of ammonium molybdate tetrahydrate, thiourea and deionized water is 0.03-0.05:1.2-1.3:6.

[0013] Preferably, in the above step S2., the solvent thermal reaction temperature is 200-220° C. and the time is 19-21 h.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0015] The Ag atoms in the present invention are doped into MoS 2-x Atomic Layer@TiO 2-y Nano-photocatalysts are made by solvothermal method to incorporate Ag atoms into MoS 2-x Atomic Layer@TiO 2-y Nano-array photocathode was prepared;

[0016] Titanium dioxide is an ideal photoelectrode material, but the band gap of original titanium dioxide is wide, and it can only use ultraviolet light in the solar spectrum. - Easy to be h + Recombination, thereby limiting its optical activity; the present invention uses a solvothermal method to prepare O-defective TiO 2-y Nanocone array, followed by Ag atoms doping into MoS 2-x Atomic Layer@TiO 2-y Preparation of nano-photocatalysts: Ag atoms are doped into MoS 2-x Atomic Layer@TiO 2-y Nanoarray photocathode, in TiO 2-y and MoS 2-x The construction of the interface heterojunction between -Ag expands the response wavelength range of titanium dioxide to the visible light and even near-infrared region, improves the separation and transfer efficiency of photogenerated electrons and holes, and improves the degradation efficiency and degradation stability of metronidazole. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The O-deficient TiO prepared in Example 2 2-y Microscopic image of a nanocone array.

[0018] Figure 2 The Ag atoms prepared in Example 2 are doped into MoS 2-x Atomic Layer@TiO 2-y Metronidazole degradation test was carried out using the nano-photocatalyst and the control as working electrodes, and the residual rate of metronidazole in the electrolyte within 30 minutes.

[0019] Figure 3 The Ag atoms prepared in Example 2 are doped into MoS 2-x Atomic Layer@TiO 2-y The residual rate of metronidazole in the electrolyte within 30 minutes after the nano-photocatalyst was subjected to an external voltage of -0.2 to -1.0 V.

[0020] Figure 4 The Ag atoms prepared in Example 2 are doped into MoS 2-x Atomic Layer@TiO 2-y When the pH value of the nano-photocatalyst is adjusted to 4-8, the residual rate of metronidazole in the electrolyte within 30 minutes.

[0021] Figure 5 The Ag atoms prepared in Example 2 are doped into MoS 2-x Atomic Layer@TiO 2-y The nano-photocatalyst was tested for degradation of electrolyte, tap water, lake water and river water, and the residual rate of metronidazole in electrolyte, tap water, lake water and river water was measured within 30 minutes. DETAILED DESCRIPTION

[0022] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention. Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art.

[0023] Example 1

[0024] In this embodiment, Ag atoms are doped into MoS 2-x Atomic Layer@TiO 2-y The preparation method of nano photocatalyst is:

[0025] S1. The titanium sheet was sequentially cleaned with deionized water, 1 mol / L hydrochloric acid, acetone and ethanol at 40kHz ultrasonic cleaning for 10 min, and dried at 60°C to obtain a clean titanium sheet; isopropyl titanate was added to acetylacetone at a volume of 0.16 times that of acetylacetone, and the mixture was stirred at 600 rpm for 18 min, and then 0.07 mol / L disodium ethylenediaminetetraacetic acid aqueous solution was added at a volume of 10 times that of acetylacetone, and the mixture was stirred for 30 min, and the titanium sheet was transferred to the inner tank of a polytetrafluoroethylene hydrothermal reactor, and the clean titanium sheet was placed in a The pretreated titanium sheet was vertically immersed in a reactor, heated to 195°C, reacted for 13 hours, taken out and washed 6 times with deionized water and ethanol, and dried to obtain a pretreated titanium sheet; the pretreated titanium sheet was placed in a tubular furnace, heated to 500°C for annealing for 50 minutes under nitrogen protection, with a nitrogen flow rate of 60 ml / min and a heating rate of 2°C / min. After cooling to room temperature, it was used as an anode, with a formic acid solution with a mass fraction of 5% as the electrolyte, the temperature of the electrolyte was 8°C, the distance between the plates was 1.5 cm, and the current was 5 mA / cm 2 The cathode was reduced for 5 min under constant current conditions, washed with deionized water and ethanol three times, and dried in a vacuum oven at 60 °C for 50 min to obtain O-deficient TiO 2-y Nanocone arrays;

[0026] S2. Mix ammonium molybdate tetrahydrate, thiourea and deionized water in a mass ratio of 0.03:1.2:6 and stir evenly, add silver nitrate 0.3 times the mass of ammonium molybdate tetrahydrate, stir at 600 rpm for 13 min, transfer to the inner tank of a polytetrafluoroethylene hydrothermal reactor, and heat the O-deficient TiO 2-y The nanocone array was immersed in water and subjected to solvent thermal reaction at 200 °C for 19 h. After being taken out, it was washed with deionized water and ethanol three times in sequence and dried in a vacuum oven at 60 °C for 25 min to obtain Ag atoms doped in MoS 2-x Atomic Layer@TiO 2-y Nano-photocatalyst.

[0027] Example 2

[0028] In this embodiment, Ag atoms are doped into MoS 2-x Atomic Layer@TiO 2-y The preparation method of nano photocatalyst is:

[0029] S1. The titanium sheet was sequentially cleaned with deionized water, 1 mol / L hydrochloric acid, acetone and ethanol at 50kHz ultrasonic cleaning for 13 minutes, and dried at 65°C to obtain a clean titanium sheet; isopropyl titanate was added to acetylacetone at a volume of 0.24 times that of acetylacetone, and the mixture was stirred at 700rpm for 20 minutes, and then 0.075 mol / L disodium ethylenediaminetetraacetic acid aqueous solution was added at a volume of 13 times that of acetylacetone, and the stirring was continued for 35 minutes, and the clean titanium sheet was transferred to the inner tank of a polytetrafluoroethylene hydrothermal reactor, and the clean titanium sheet was placed in a The pretreated titanium sheet was vertically immersed in a reactor, heated to 200°C, reacted for 14 hours, taken out and washed with deionized water and ethanol for 7 times, and dried to obtain a pretreated titanium sheet; the pretreated titanium sheet was placed in a tubular furnace, heated to 525°C for annealing for 60 minutes under nitrogen protection, with a nitrogen flow rate of 70 ml / min and a heating rate of 3°C / min. After cooling to room temperature, it was used as an anode, with a formic acid solution with a mass fraction of 8% as the electrolyte, the temperature of the electrolyte was 10°C, the distance between the plates was 1.5 cm, and the current was 5 mA / cm 2 The TiO2O3 was subjected to cathode reduction under constant current conditions for 7 min, washed with deionized water and ethanol four times, and dried in a vacuum oven at 60 °C for 60 min to obtain TiO2O3 with O defects. 2-y Nanocone arrays;

[0030] S2. Mix ammonium molybdate tetrahydrate, thiourea and deionized water in a mass ratio of 0.04:1.25:6 and stir evenly, add silver nitrate 0.4 times the mass of ammonium molybdate tetrahydrate, stir at 700 rpm for 15 min, transfer to the inner tank of a polytetrafluoroethylene hydrothermal reactor, and heat the O-deficient TiO 2-yThe nanocone array was immersed in water and subjected to solvent thermal reaction at 210 °C for 20 h. After being taken out, it was washed with deionized water and ethanol four times in sequence and dried in a vacuum oven at 60 °C for 30 min to obtain Ag atoms doped in MoS 2-x Atomic Layer@TiO 2-y Nano-photocatalyst.

[0031] Example 3

[0032] In this embodiment, Ag atoms are doped into MoS 2-x Atomic Layer@TiO 2-y The preparation method of nano photocatalyst is:

[0033] S1. The titanium sheet was sequentially cleaned with deionized water, 1 mol / L hydrochloric acid, acetone and ethanol at 60kHz ultrasonic cleaning for 15 minutes, and dried at 70°C to obtain a clean titanium sheet; isopropyl titanate was added to acetylacetone at a volume of 0.34 times that of acetylacetone, and the mixture was stirred at 800 rpm for 22 minutes, and then 0.08 mol / L disodium ethylenediaminetetraacetic acid aqueous solution was added at a volume of 16 times that of acetylacetone, and the stirring was continued for 40 minutes, and the titanium sheet was transferred to the inner tank of a polytetrafluoroethylene hydrothermal reactor, and the clean titanium sheet was vertically placed in a 100-meter-high temperature reactor. Immerse in a reactor, heat to 205°C, react for 15 hours, take out and wash 8 times with deionized water and ethanol, dry to obtain a pretreated titanium sheet; place the pretreated titanium sheet in a tube furnace, heat to 550°C for annealing for 70 minutes under nitrogen protection, the nitrogen flow rate is 80 ml / min, the heating rate is 3°C / min, and after cooling to room temperature, it is used as an anode, and a formic acid solution with a mass fraction of 5-10% is used as an electrolyte, the temperature of the electrolyte is 12°C, the distance between the plates is 1.5 cm, and the current is 5 mA / cm 2 The cathode was reduced for 8 min under constant current conditions, washed with deionized water and ethanol for 5 times, and dried in a vacuum oven at 60 °C for 70 min to obtain O-deficient TiO 2-y Nanocone arrays;

[0034] S2. Mix ammonium molybdate tetrahydrate, thiourea and deionized water in a mass ratio of 0.05:1.3:6 and stir evenly, add silver nitrate 0.5 times the mass of ammonium molybdate tetrahydrate, stir at 800 rpm for 17 min, transfer to the inner tank of a polytetrafluoroethylene hydrothermal reactor, and heat the O-deficient TiO 2-y The nanocone array was immersed in water and subjected to solvent thermal reaction at a temperature of 220°C for 21 h. After being taken out, it was washed with deionized water and ethanol for 5 times in sequence and dried in a vacuum oven at 60°C for 35 min to obtain Ag atoms doped in MoS 2-x Atomic Layer@TiO 2-y Nano-photocatalyst.

[0035] Effect example

[0036] The Ag atoms prepared in Examples 1-3 were doped into MoS 2-x Atomic Layer@TiO 2-y Nano-photocatalyst and comparative example were used as working electrode for metronidazole degradation test. The comparative example was TiO2, TiO 2-y , TiO 2-y @MoS2,TiO 2-y @MoS 2-x , TiO2, TiO 2-y , TiO 2-y @MoS2,TiO 2-y @MoS 2-x and TiO 2-y @MoS 2-x -Ag are denoted as T, OvT, OvTMS, OvTMSv, and OvTMSvA;

[0037] The test method is as follows:

[0038] The reaction was carried out in a 50mL double-layer electrolytic cell (circulating condensed water at 25°C was introduced into the system during the reaction to ensure constant temperature), with 30mL of 0.1mol / L Na2SO4 as the electrolyte (containing 30ppm metronidazole), Ag / AgCl as the reference electrode, the Pt sheet as the counter electrode, and the nanophotocatalyst prepared in the embodiment as the working electrode (the area of ​​the counter electrode and the working electrode was 2×2cm). During the reaction, the system was adjusted to pH 4 to 8 with 0.5mol / L H2SO4 and NaOH, the applied voltage was adjusted to -0.2 to -1.0V (vs.RHE), and the potassium persulfate concentration was adjusted to 4 to 16mmol / L. Before the reaction started, 30mL of the electrolyte was added to the electrolytic cell, and the electrode was completely vertically immersed in the solution, and the adsorption was stirred at 100rmp in the dark for 30min before testing;

[0039] The test used a voltage applied on a Chenhua 660E electrochemical workstation, and a 300W xenon lamp was used to vertically irradiate the photocathode (a filter was installed in front of the xenon lamp to ensure that the reaction irradiation wavelength λ>400nm), and the system was stirred at a constant speed of 100rmp. The concentration after dark adsorption was taken as the zero point, and 3mL of water sample was taken every 5min for UV-visible light absorption test. After the test, the water sample was returned to the reactor, and then tap water, lake water and river water were used for testing (the water sample was filtered through a 0.22μm organic filter membrane after it was retrieved, and then used to prepare the electrolyte.

[0040] The experimental results of the examples and the comparative examples show that in Example 2, under the conditions of pH 5, applied voltage of -0.6 V, and potassium persulfate concentration of 8 mmol / L, the degradation efficiency of metronidazole after 30 minutes is 95.47%, which is 4 times higher than that of the unmodified material, indicating that the present invention uses the solvothermal method to prepare TiO with O defects.2-y Nanocone array, followed by Ag atoms doping into MoS 2-x Atomic Layer@TiO 2-y Preparation of nano-photocatalysts: Ag atoms are doped into MoS 2-x Atomic Layer@TiO 2-y Nanoarray photocathode, in TiO 2-y and MoS 2-x The construction of the interface heterojunction between -Ag expands the response wavelength range of titanium dioxide to the visible light and even near-infrared region, improves the separation and transfer efficiency of photogenerated electrons and holes, and improves the degradation efficiency and degradation stability of metronidazole.

[0041] Obviously, the above embodiments are merely examples for clearly illustrating the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. However, these obvious changes or modifications derived from the spirit of the present invention are still within the scope of protection of the present invention.

Claims

1. Ag atom doping into MoS 2-x Atomic Layer@TiO 2-y The method for preparing a nano photocatalyst is characterized in that: The specific steps include: S1. Place the pretreated titanium sheet in a tube furnace, heat it to 500-550℃ and anneal it for 50-70min under nitrogen protection, and use it as an anode after cooling to room temperature. Use 5-10% formic acid solution as electrolyte at 5mA / cm 2 The cathode was reduced for 5-8 min under constant current conditions, washed with deionized water and ethanol for 3-5 times, and dried in a vacuum oven at 60 °C for 50-70 min to obtain O-deficient TiO 2-y Nanocone arrays; S2. Mix ammonium molybdate tetrahydrate, thiourea and deionized water and stir evenly, add silver nitrate 0.3 to 0.5 times the mass of ammonium molybdate tetrahydrate, stir at 600 to 800 rpm for 13 to 17 minutes, transfer to the inner tank of a polytetrafluoroethylene hydrothermal reactor, and heat the TiO 2-y The nanocone array was immersed in water for solvothermal reaction, and then washed with deionized water and ethanol for 3 to 5 times, and dried in a vacuum oven at 60 °C for 25 to 35 min to obtain Ag atoms doped in MoS 2-x Atomic Layer@TiO 2-y Nano-photocatalysts; The process of pretreating the titanium sheet is as follows: adding isopropyl titanate in an amount of 0.16 to 0.34 times the volume of acetylacetone to acetylacetone, stirring and mixing at 600 to 800 rpm for 18 to 22 minutes, then adding a 0.07 to 0.08 mol / L aqueous solution of disodium ethylenediaminetetraacetate in an amount of 10 to 16 times the volume of acetylacetone, continuing stirring for 30 to 40 minutes, transferring to a polytetrafluoroethylene hydrothermal reactor liner, vertically immersing the cleaned titanium sheet in the reactor, heating to 195 to 205° C., reacting for 13 to 15 hours, taking out and washing with deionized water and ethanol for 6 to 8 times, and drying.

2. The Ag atom-doped MoS according to claim 1 2-x Atomic Layer@TiO 2-y The method for preparing a nano photocatalyst is characterized in that: The process of cleaning the titanium sheet is as follows: the titanium sheet is cleaned with deionized water, 1 mol / L hydrochloric acid, acetone and ethanol in sequence at 40-60 kHz ultrasonic cleaning for 10-15 minutes, and dried at 60-70°C.

3. The Ag atom-doped MoS according to claim 1 2-x Atomic Layer@TiO 2-y The method for preparing a nano photocatalyst is characterized in that: In the above step S1., the nitrogen flow rate is 60-80 ml / min, and the heating rate is 2-3° C. / min.

4. The Ag atom-doped MoS according to claim 1 2-x Atomic Layer@TiO 2-y The method for preparing a nano photocatalyst is characterized in that: In the above step S1., the temperature of the electrolyte is 8-12° C., and the distance between the electrode plates is 1.5 cm.

5. The Ag atom-doped MoS according to claim 1 2-x Atomic Layer@TiO 2-y The method for preparing a nano photocatalyst is characterized in that: In the above step S2., the mass ratio of ammonium molybdate tetrahydrate, thiourea and deionized water is 0.03-0.05:1.2-1.3:

6.

6. The Ag atom-doped MoS according to claim 1 2-x Atomic Layer@TiO 2-y The method for preparing a nano photocatalyst is characterized in that: In the above step S2., the solvent thermal reaction temperature is 200-220° C. and the time is 19-21 hours.

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