Novel technology for photocatalytic decomposition of hydrogen phosphide and novel method for preparing photocatalyst

Abstract

According to the novel technology for photocatalytic decomposition of phosphine and the novel method for preparing the photocatalyst, the novel technology for photocatalytic decomposition of phosphine through a photo-initiated composite photocatalyst is innovatively introduced, the photocatalytic active center in the composite photocatalyst is ferroferric oxide, and the chemical catalytic active center is a chemical nickel-plated layer on the surface of a one-dimensional nano material; the two components synergistically catalyze and decompose hydrogen phosphide; the catalyst is simple in preparation method and low in cost, and the nickel utilization rate is further greatly improved. The technology efficiently catalyzes and decomposes the hydrogen phosphide-containing waste gas to generate elemental phosphorus and hydrogen, and provides an ideal way for recycling phosphorus industrial tail gas.

Description

Technical Field

[0001] The invention belongs to the technical field of phosphorus industrial waste gas resource utilization and pollution emission control, and in particular relates to a new technology for photocatalytic decomposition of phosphine and a new method for preparing a photocatalyst. Background Art

[0002] Regarding the removal and resource utilization of phosphine in industrial waste gas, many solutions have been proposed in the past few decades. Conventional technologies including wet scrubbing and thermal combustion will eventually convert the input gas into low-value water-soluble phosphates, phosphoric acid and / or other oxides, resulting in secondary pollution and waste of resources. Some improved methods, such as catalytic oxidation and gas-solid adsorption, are easier to eliminate phosphine in practice, but the oxidant and adsorbent are not recyclable and reusable.

[0003] The direct decomposition of phosphine and proper purification can produce clean energy hydrogen and expensive semiconductor-grade high-purity yellow phosphorus, which is an important phosphorus resource recovery technology. However, its pyrolysis temperature is as high as 600°C, and appropriate catalysts can reduce it to a practical range. Patent CN102936371A reports a low-cost supported iron-based alloy catalyst, which uses cheap natural halloysite nanotubes (HNTs) as a carrier and achieves a phosphine decomposition rate of nearly 100% at 420°C. The catalyst is limited to the alloy structure, and the utilization efficiency of the active nickel component is low. Patent ZL 201810242499.5 proposes a nickel-plated spinel catalyst for phosphine decomposition and a preparation method thereof, with trace Ni plating and NiFe 2 O 4 Spinel particles are active species with the advantages of low cost, high nickel utilization, good medium-temperature catalytic activity, etc., which significantly improves the utilization efficiency of nickel. However, the preparation method of the catalyst is cumbersome and complicated, which limits its industrial application. In addition, the above are all traditional chemical catalytic decomposition technologies. Summary of the invention

[0004] A new technology for photocatalytic decomposition of phosphine and a new method for preparing photocatalysts, which innovatively introduces a new technology for photoinduced composite photocatalyst catalytic decomposition of phosphine. The photocatalytic active center in the composite photocatalyst is Fe 3 0 4 The chemical catalytic active center is the chemically plated nickel layer on the surface of the one-dimensional nanomaterial. The two synergistically catalyze the decomposition of phosphine, and the atomic utilization rate of nickel is significantly improved.

[0005] The present invention is achieved in that:

[0006] 1) The one-dimensional nanomaterial is treated by acidification, silane modification, and chemical nickel plating to form a nickel coating;

[0007] 2) immersing the one-dimensional nanomaterial coated with a nickel layer obtained in 1) in a mixed solution containing a soluble iron salt and a ferrous salt, and aging for 4 hours at a certain temperature and a pH of 10;

[0008] 3) The aged material in 2) is vacuum dried, ground and screened to obtain the nickel-plated "hanging" Fe 3 0 4 Nanoparticle composite nanocatalytic materials (Fe 3 0 4 -Ni@HNTs-NH 2 ), which can be used for the photocatalytic decomposition of phosphine to produce elemental phosphorus and hydrogen.

[0009] The new method for preparing the photocatalyst comprises: Fe in a mixed solution of a soluble iron salt and a ferrous salt 3+ / Fe 2+ The molar ratio is 3:1-2:1.

[0010] The composite photocatalyst is a one-dimensional nanomaterial with natural or artificial synthesis as carrier. 3 O 4 The invention relates to a composite nanocatalyst in which the photocatalytic active site is the nickel coating on the surface of the one-dimensional nanomaterial and the chemical catalytic active site is the nickel coating.

[0011] The one-dimensional nanomaterials include, but are not limited to, halloysite (HNTs), carbon nanotubes (CNTs), SiO 2 Nanowires.

[0012] The silane according to claim 5, includes but is not limited to 3-aminopropyltriethoxysilane (APTES), N-(n-butyl)-3-aminopropyltrimethoxysilane, and Y-aminopropyltrimethoxysilane (APTMS).

[0013] Further:

[0014] The obtained photocomposite catalyst can efficiently remove phosphine under different temperatures and photoinitiated conditions.

[0015] The advantages of the present invention are: light initiation significantly improves the phosphine degradation rate of the catalyst at all temperatures; the catalyst preparation method is simple, the cost is low, and the nickel utilization rate is further greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Raw HNTs (a), nickel-plated HNTs (b), Fe 3 O 4 -Ni@HNTs-NH 2 (c) TEM image.

[0017] Figure 2 For nickel-plated HNTs, Fe 3 O 4 -Ni@HNTs-NH 2 A diagram showing the catalytic degradation effect of the catalyst on phosphine (1 v / v%) under different photoinitiation conditions.

[0018] Figure 3 (a) is Fe 3 O 4 -Ni@HNTs-NH 2 EPR spectra after different time of light initiation at 395nm wavelength; (b) PH 3 In Ni(111) and Fe 3 O 4 (111) Theoretical calculation of adsorption energy for direct decomposition and catalytic decomposition on the crystal surface. DETAILED DESCRIPTION

[0019] The following embodiments are provided to facilitate a better understanding of the present application, but are not intended to limit the present application.

[0020] Example 1

[0021] A new technology for photocatalytic decomposition of phosphine and a new method for preparing photocatalysts, which for the first time uses light-triggered technology to catalytically decompose phosphine, and under the synergistic effect of composite photocatalysts, phosphine is efficiently catalytically decomposed; the photocatalyst is Fe 3 O 4 The composite photocatalyst is composed of a chemically plated nickel (Ni) layer on the surface of HNTs and halloysite; using soluble nickel salt, soluble iron salt, soluble ferrous salt and nano HNTs as raw materials, the Ni-plated layer "suspended" Fe 3 O 4 The composite nano-catalytic material of nano-particles comprises the following specific steps:

[0022] 1) Weigh 2.5 g HNTs into a 50 mL round-bottom flask, then add 20 ml toluene and 3 mL APTES, mix well, heat in an oil bath at 120 ° C, condense and reflux for 12 h, filter after the reaction is completed, wash with toluene and ethanol for several times, and vacuum dry at 100 ° C for 5 hours to obtain the product with aminosilane modified on the surface of HNTs, which is recorded as HNTs-NH 2 ; 1.0gHNTs-NH 2 Dissolve in 20ml SnCl 2 After stirring at room temperature for 20 min, the solution was filtered and the precipitate was washed once to remove the excess Sn adsorbed on the surface. 2+ , then add 20 ml PdCl 2The solution was stirred for 20 min and then filtered; the solid obtained after sensitization and activation was dissolved in 40 ml of Ni chemical plating solution, heated and stirred at 60 ° C for 20 min, and the pH was adjusted to about 9.0 with ammonia water; the solution was filtered and washed with deionized water for 3 times, and the obtained precipitate was vacuum dried at 70 ° C for 6 hours to form a nanocatalyst with a nickel coating (Ni@HNTs-NH 2 ). The above solutions were prepared as follows:

[0023] ①Ni chemical plating solution: weigh 5.90g NiCl 2 6H 2 O was placed in a beaker, and an appropriate amount of distilled water was added to dissolve it. Then 7.90 g of NaH 2 PO 3 ·H 2 O, after stirring evenly, 22.05g Na 3 C 6 H 5 O 7 ·2H 2 Dissolve O in the mixed solution, mix well, add to a 250ml volumetric flask, shake well and set aside;

[0024] ②SnCl 2 Solution: 7.0 g SnCl 2 ·2H 2 Place O in a beaker, add appropriate amount of distilled water, stir evenly, then add 7.5 ml of concentrated HCl, dilute to 100 ml volumetric flask after dissolving, shake well for use (prepare immediately before use);

[0025] ③PdCl 2 Solution: 0.25 g PdCl 2 Place in a beaker, add appropriate amount of distilled water, stir evenly, then add 2.5ml of concentrated HCl, mix evenly, make up to volume in a 1000ml volumetric flask, shake well and set aside.

[0026] 2) 1.165 g FeCl 3 6H 2 O and 0.6g FeSO 4 7H 2 O(Fe 3+ / Fe 2+ The molar ratio is 2:1) and 0.5 g Ni@HNTs-NH 2 . Heat and stir at 60°C under nitrogen protection, and add 8 mol / L NH 3 ·H 2 O solution until the pH is 9-10, then aged at 70°C for 4h;

[0027] 3) The aged material in 2) was filtered and washed with deionized water for 3 times, and vacuum dried at 70°C for 6 hours to finally obtain the nickel-plated "hanging" Fe 3 O 4 Nanoparticle composite nanocatalytic materials (Fe 3 O 4 -Ni@HNTs-NH 2 ), whose Ni content is 0.46%, can be used for photocatalytic decomposition of phosphine to produce elemental phosphorus and hydrogen.

[0028] The obtained photocatalyst containing 0.46% Ni has a high efficiency of 6000 ml·(h·g cat ) -1 The removal rate of the initial concentration of 1v / v%) reached 89%, the residual phosphine concentration was only 0.11%, and the unit catalytic efficiency of Ni was as high as 18889.9ml·(min·g Ni ) -1 .

[0029] The SEM images of the obtained materials are shown in the attached Figure 1 , indicating that nickel is uniformly coated on the surface of HNTs in the form of a coating, and its Fe 3 O 4 Nanoparticles are "suspended" on the surface of the nickel coating; Figure 2 It shows that Fe 3 O 4 -Ni@HNTs-NH 2 The catalytic degradation performance of phosphine was significantly improved under the light initiation of wavelength 395nm; Figure 3 (a) shows that Fe 3 O 4 -Ni@HNTs-NH 2 After different lengths of light initiation, oxygen vacancies are generated, which are beneficial to the catalytic decomposition reaction. Figure 3 (b) Theoretical calculation results verify that Fe 3 O 4 and Ni plating as a catalyst effectively lowers the pH 3 Energy barrier for catalytic decomposition reactions.

[0030] Example 2

[0031] A new technology for photocatalytic decomposition of phosphine and a new method for preparing photocatalysts, which for the first time uses light-triggered technology to catalytically decompose phosphine, and under the synergistic effect of composite photocatalysts, phosphine is efficiently catalytically decomposed; the photocatalyst is Fe 3 O 4The composite photocatalyst is composed of a chemically plated nickel (Ni) layer on the surface of HNTs and halloysite; using soluble nickel salt, soluble iron salt, soluble ferrous salt and nano HNTs as raw materials, the Ni-plated layer "suspended" Fe 3 0 4 The composite nano-catalytic material of nano-particles comprises the following specific steps:

[0032] 1) Weigh 2.5 g HNTs into a 50 mL round-bottom flask, then add 20 ml toluene and 3 mL APTES, mix well, heat in an oil bath at 120 ° C, condense and reflux for 12 h, filter after the reaction is completed, wash with toluene and ethanol for several times, and vacuum dry at 100 ° C for 5 hours to obtain the product with aminosilane modified on the surface of HNTs, which is recorded as HNTs-NH 2 ; 1.0gHNTs-NH 2 Dissolve in 100ml SnCl 2 After stirring at room temperature for 20 min, the solution was filtered and the precipitate was washed once to remove the excess Sn adsorbed on the surface. 2+ , then add 100 ml PdCl 2 The solution was stirred for 20 min and then filtered; the solid obtained after sensitization and activation was dissolved in 200 ml Ni chemical plating solution, heated and stirred at 60 ° C for 20 min, and the pH was adjusted to about 9.0 with ammonia water; the solution was filtered and washed with deionized water for 3 times, and the obtained precipitate was vacuum dried at 70 ° C for 6 hours to form a nanocatalyst with a nickel coating (Ni@HNTs-NH 2 ). The above solutions were prepared as follows:

[0033] ①Ni chemical plating solution: weigh 5.90g NiCl 2 6H 2 O was placed in a beaker, and an appropriate amount of distilled water was added to dissolve it. Then 7.90 g of NaH 2 PO 3 ·H 2 O, after stirring evenly, 22.05g Na 3 C 6 H 5 O 7 ·2H 2 Dissolve O in the mixed solution, mix well, add to a 250ml volumetric flask, shake well and set aside;

[0034] ②SnCl 2 Solution: 7.0 g SnCl 2 ·2H 2Place O in a beaker, add appropriate amount of distilled water, stir evenly, then add 7.5 ml of concentrated HCl, dilute to 100 ml volumetric flask after dissolving, shake well for use (prepare immediately before use);

[0035] ③PdCl 2 Solution: 0.25 g PdCl 2 Place in a beaker, add appropriate amount of distilled water, stir evenly, then add 2.5ml of concentrated HCl, mix evenly, make up to volume in a 1000ml volumetric flask, shake well and set aside.

[0036] 2) 1.165 g FeCl 3 6H 2 O and 0.6g FeSO 4 7H 2 O(Fe 3+ / Fe 2+ The molar ratio is 2:1) and 0.5 g Ni@HNTs-NH 2 . Heat and stir at 60°C under nitrogen protection, and add 8 mol / L NH 3 ·H 2 O solution until the pH is 9-10, then aged at 70°C for 4h;

[0037] 3) The aged material in 2) was filtered and washed with deionized water for 3 times, and vacuum dried at 70°C for 6 hours to finally obtain Fe 3 O 4 -Ni@HNTs-NH 2 , whose Ni content is 1.51%, can be used for photocatalytic decomposition of phosphine to produce elemental phosphorus and hydrogen.

[0038] The obtained photocatalyst containing 1.51% Ni has a high efficiency of 6000 ml·(h·g cat ) -1 The removal rate of the initial concentration of 1v / v%) was as high as 95%, the residual phosphine concentration was only 0.06%, and the unit catalytic efficiency of Ni was 6204.9ml·(min.g Ni ) -1 .

[0039] Although the present application has been disclosed above through the description of the specific embodiments of the present application, it should be understood that those skilled in the art can design various modifications, improvements or equivalents to the present application within the spirit and scope of the attached scheme. These modifications, improvements or equivalents should also be considered to be included in the scope of protection claimed in the present application.

Claims

1. A new technology for photocatalytic decomposition of phosphine and a new method for preparing a photocatalyst, characterized in that: For the first time, light-triggered technology was used to catalytically decompose phosphine. Under the action of the composite photocatalyst, phosphine could be efficiently catalytically decomposed into elemental phosphorus and hydrogen.

2. A new technology for photocatalytic decomposition of phosphine according to claim 1, characterized in that: Light sources for photoinitiation include ultraviolet light and visible light.

3. The new technology for photocatalytic decomposition of phosphine according to claim 1 is characterized in that: The light-initiating methods include single-point or multi-point point light source irradiation, single-surface or multi-surface surface light source irradiation.

4. The new technology for photocatalytic decomposition of phosphine according to claim 1 is characterized in that: The contact modes between phosphine gas and light source include direct contact and indirect contact.

5. The novel method for preparing a photocatalyst according to claim 1, characterized in that: The photocatalyst is a composite photocatalyst composed of ferroferric oxide and a chemically plated nickel layer on the surface of a one-dimensional nanomaterial. The composite nanocatalyst is prepared by chemically plating nickel and precipitation method using soluble nickel salt, soluble iron salt, soluble ferrous salt and natural or synthetic one-dimensional nanomaterial as raw materials, and the composite nanocatalyst material with ferroferric oxide nanoparticles "suspended" on the nickel-plated layer is prepared. The process includes the following steps: 1) The one-dimensional nanomaterial is treated by acidification, silane modification, and chemical nickel plating to form a nickel coating; 2) immersing the one-dimensional nanomaterial coated with a nickel layer obtained in 1) in a mixed solution containing a soluble iron salt and a ferrous salt, and aging for 4 hours at a certain temperature and a pH of 10; 3) The aged material in 2) is vacuum dried, ground and screened to obtain a composite nano-catalytic material with nickel-plated layers "suspending" ferroferric oxide nanoparticles, which can be used for photocatalytic decomposition of phosphine to produce elemental phosphorus and hydrogen.

6. The novel method for preparing a photocatalyst according to claim 5, characterized in that: Fe3+ / Fe in a mixed solution of soluble iron salt and ferrous salt 2+ The molar ratio is 1.1:1 to 2:1, preferably, the molar ratio is 1.5:1-2:1; the aging temperature is 40-90°C, preferably, the aging temperature is 60-70°C.

7. The composite photocatalyst according to claim 5, characterized in that: It is a composite nanocatalyst with natural or artificially synthesized one-dimensional nanomaterials as carriers, ferroferric oxide as photocatalytic active sites, and the nickel coating on the surface of the one-dimensional nanomaterials as chemical catalytic active sites.

8. The one-dimensional nanomaterial according to claim 5, comprising but not limited to halloysite, carbon nanotubes, and SiO2 nanowires.

9. The silane according to claim 5, including but not limited to 3-aminopropyltriethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane.

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