阅读说明：本技术 高比表面积有序大介孔尖晶石镓酸锌及其制备方法 (High specific surface area ordered large mesoporous spinel zinc gallate and preparation method thereof ) 是由 赖小勇 马金苗 王晓中 于 2020-04-15 设计创作，主要内容包括：本发明涉及高比表面积有序大介孔尖晶石镓酸锌,以及介孔氧化硅为硬模板来可控合成有序大介孔镓酸锌的方法。其特点是：比表面积为92-138m<Sup>2</Sup>/g,孔径分布在10-12nm。本发明方法的优点在于：1)通过水热法制备具有较大孔壁联通孔的介孔氧化硅,采用纳米浇筑法使前驱体可以较为顺利地进入孔道中,在刻蚀模板后可以很好的复制得到有序大介孔镓酸盐；2)本发明所得的镓酸锌材料孔径可以达到10.7nm,孔壁厚度约为5nm,大的孔径有利于分子的传输与扩散；比表面积高达138m<Sup>2</Sup>/g,能够提供更多的表面活性位点。3)本发明制备的镓酸锌材料在降解染料等污染物具有很好的效果,另外在光催化产氢方面也有较好的效果。(The invention relates to ordered large mesoporous spinel zinc gallate with high specific surface area and a method for controllably synthesizing the ordered large mesoporous zinc gallate by using mesoporous silicon oxide as a hard template. The method is characterized in that: the specific surface area is 92-138m 2 The pore size distribution is 10-12 nm. The method has the advantages that: 1) preparing mesoporous silicon oxide with larger hole wall connecting holes by a hydrothermal method, enabling a precursor to smoothly enter a pore channel by adopting a nano-casting method, and well copying after a template is etched to obtain ordered large mesoporous gallate; 2) the aperture of the zinc gallate material obtained by the invention can reach 10.7nm, the thickness of the hole wall is about 5nm, and the large aperture is beneficial to the transmission and diffusion of molecules; the specific surface area is as high as 138m 2 And/g, can provide more surface active sites. 3) The zinc gallate material prepared by the invention has good effect in degrading pollutants such as dye and the like, and also has good effect in the aspect of photocatalytic hydrogen production.)

1. A high specific surface area ordered large mesoporous spinel zinc gallate is characterized in that: the specific surface area is 92-138m²The pore size distribution is 10-12 nm.

2. A preparation method of ordered large mesoporous spinel zinc gallate with high specific surface area is characterized by comprising the following steps:

1) firstly, mixing and stirring a surfactant, water and hydrochloric acid until the surfactant is completely dissolved, adding n-butyl alcohol and stirring, then adding tetraethoxysilane and stirring, carrying out hydrothermal reaction, cooling, carrying out suction filtration, washing and drying, then calcining in air to remove the surfactant, and grinding to obtain white powdery ordered mesoporous silicon dioxide;

2) mixing zinc salt and a gallium salt precursor, adding the mixture into a sample tube, putting the sample tube into an oven with a certain temperature, adding the ordered mesoporous silica obtained in the step 1) into the sample tube as a hard template after the mixture is completely melted and mixed, and fully shaking and grinding the mixture to ensure that the precursor solution fully enters a mesoporous silica pore channel;

wherein the zinc salt is zinc nitrate trihydrate, the gallium salt is gallium nitrate x hydrate, and the molar ratio of the zinc salt to the gallium salt is 1: 2, mixing;

3) putting the obtained sample into a muffle furnace for calcining;

4) and putting the calcined product into a sodium hydroxide solution, stirring, and centrifuging to remove the mesoporous silica template to obtain the ordered large mesoporous spinel zinc gallate with the high specific surface area.

3. The method for preparing the high-specific-surface-area ordered large-mesoporous spinel zinc gallate according to claim 2, wherein the method comprises the following steps:

step 1) is concretely to mix P₁₂₃72g, 2600mL deionized water and 120mL 37% concentrated hydrochloric acid, mixing at room temperature, stirring until completely dissolved, transferring into a four-neck flask, stirring in a 35 ℃ water bath for 12 hours, adding 72g n-butanol, stirring for 2 hours, adding 154.8g TEOS, stirring for one day, performing suction filtration on a solid-liquid mixture in the four-neck flask, transferring to a vacuum pump, and performing vacuum filtrationAnd performing hydrothermal reaction in a reaction kettle in an oven for 24 hours, taking out, naturally cooling, performing suction filtration and washing by using deionized water until the reaction kettle is neutral, putting the reaction kettle into a crucible, drying the reaction kettle in a drying oven at 70 ℃ overnight, taking out, grinding and calcining, controlling the heating rate to be 1-2 ℃/min, the calcining temperature to be 550 ℃ and the calcining time to be 6 hours.

4. The method for preparing the high-specific-surface-area ordered large-mesoporous spinel zinc gallate according to claim 3, wherein the method comprises the following steps: the hydrothermal reaction temperature in the step 1) is 40-140 ℃.

5. The method for preparing the high-specific-surface-area ordered large-mesoporous spinel zinc gallate according to claim 2, wherein the method comprises the following steps: the step 2) of fully shaking and grinding specifically means shaking and grinding for 1 time every 5-30min, and shaking and grinding for 3-5 times in total.

6. The method for preparing the high-specific-surface-area ordered large-mesoporous spinel zinc gallate according to claim 2, wherein the method comprises the following steps: in the step 2), the mass ratio of the gallium salt to the ordered mesoporous silica hard template is 1: 1.13-1:3.69, wherein the mass ratio of the zinc salt to the ordered mesoporous silica hard template is 1: 3.16-1:10.35.

7. The method for preparing the high-specific-surface-area ordered large-mesoporous spinel zinc gallate according to claim 2, wherein the method comprises the following steps: the volume of the precursor in the step 2) accounts for 20-40% of the pore volume of the mesoporous silica.

8. The method for preparing the high-specific-surface-area ordered large-mesoporous spinel zinc gallate according to claim 2, wherein the method comprises the following steps: the calcining temperature in the step 3) is 500-850 ℃, the heating rate is 1-3 ℃/min, and the calcining time is 2-10 h.

9. The method for preparing high specific surface area ordered large mesoporous spinel zinc gallate according to claim 8, wherein: wherein the calcining heating rate is 1-2 ℃/min, the calcining temperature is 550 ℃, and the calcining time is 6 h.

10. The method for preparing the high-specific-surface-area ordered large-mesoporous spinel zinc gallate according to claim 2, wherein the method comprises the following steps: the concentration of the sodium hydroxide solution in the step 4) is 2-10M.

Technical Field

The invention relates to ordered large mesoporous spinel zinc gallate with high specific surface area and a method for controllably synthesizing the ordered large mesoporous zinc gallate by using mesoporous silicon oxide as a hard template.

Background

Since the first reports of the synthesis of mesoporous materials in the 90 s of the 20 th century by researchers in Japan and scientists of Mobil corporation, the research on the mesoporous materials has attracted great attention; later the StuCky group of silicon-based SBA series further improved the pore size of mesoporous materials. Nanomaterials, which are already close in size to the wavelength of light, exhibit characteristics, such as melting point, magnetic, optical, thermal, electrical conductivity, etc., that are often different from the properties exhibited by the material in its bulk state, due to the special effect of their large surface area. In addition, the mesoporous structure also has the performances of large specific surface area, adjustable aperture, good pore connectivity and the like. The unique porous structure provided by mesoporous materials has revolutionized many areas of research over the past few decades.

The method is characterized in that a formed inorganic mesoporous material such as silicon oxide is used as a template, generally a porous silicon oxide template, then a precursor is filled into a pore channel, and the template is removed by a physical or chemical method to obtain an ordered mesoporous material filled in a reversed phase.

The ordered silicon oxide template is prepared by adding a surfactant, utilizing the hydrophilic and hydrophobic characteristics of the surfactant to enable a silicon source to be capable of arranging hydrophobic ends of surfactant micelles, hydrothermally forming a pore channel, and then removing the surfactant in the pore channel, so that the ordered silicon oxide template can be used as a template to prepare other ordered mesoporous materials such as metal oxides. In general, a method of removing silicon oxide as a hard template is to perform etching by reacting with a sodium hydroxide solution or a hydrofluoric acid solution.

The synthesis of zinc gallate materials is mostly to synthesize nanoflowers or nanoparticles by solvothermal, sol-gel and other methods, but few materials report ordered large mesoporous ZnGa₂O₄Influence on photocatalytic performance. ZnGa₂O₄Due to its unique electronic structure. Zhang et al reported ZnGa prepared by sol-gel method₂O₄Para methyleneThe blue has better degradation performance, and 97 percent (Zhang W, Zhang J, Lan X, et al. Photocalalytical performance of ZnGa2O4 for degradation of methyl blue and its improved side while with Cd [ J ] is degraded in 45min]Catalysis Communications,2010,11(14): 0-1108); sun et al reported that ZnGa was synthesized by a rapid, simple, microwave-assisted hydrothermal method₂O₄Has more excellent dye degradation performance than P25 (Sun M, Li D, Zhang W, et al. Rapid microwave hydraulic synthesis of ZnGa2O4with high photocatalytic activity waterborne compatibility in air and dye liquid water [ J].Journal of Solid State Chemistry,2012,190(none):135-142.)。

Disclosure of Invention

One of the purposes of the invention is to provide the ordered large-mesoporous spinel zinc gallate with high specific surface area, which has good effect on degrading pollutants such as dye;

the second purpose of the invention is to provide a preparation method of the high-specific surface area ordered large-mesoporous spinel zinc gallate.

The high specific surface area ordered large mesoporous spinel zinc gallate is characterized in that: the specific surface area is 92-138m²The pore size distribution is 10-12 nm.

The preparation method of the ordered large-mesoporous spinel zinc gallate with the high specific surface area is characterized by comprising the following steps of:

1) firstly, mixing and stirring a surfactant, water and hydrochloric acid until the surfactant is completely dissolved, adding n-butyl alcohol and stirring, then adding tetraethoxysilane and stirring, carrying out hydrothermal reaction, cooling, carrying out suction filtration, washing and drying, then calcining in air to remove the surfactant, and grinding to obtain white powdery ordered mesoporous silicon dioxide;

2) mixing zinc salt and a gallium salt precursor, adding the mixture into a sample tube, putting the sample tube into an oven with a certain temperature, adding the ordered mesoporous silica obtained in the step 1) into the sample tube as a hard template after the mixture is completely melted and mixed, and fully shaking and grinding the mixture to ensure that the precursor solution fully enters a mesoporous silica pore channel;

wherein the zinc salt is zinc nitrate trihydrate, the gallium salt is gallium nitrate x hydrate, and the molar ratio of the zinc salt to the gallium salt is 1: 2, mixing;

3) putting the obtained sample into a muffle furnace for calcining;

4) and putting the calcined product into a sodium hydroxide solution, stirring, and centrifuging to remove the mesoporous silica template to obtain the ordered large mesoporous spinel zinc gallate with the high specific surface area.

Step 1) is concretely to mix P₁₂₃72g, 2600mL deionized water and 120mL 37% concentrated hydrochloric acid, mixing and stirring at room temperature until the components are completely dissolved, transferring the mixture into a four-neck flask, stirring in 35 ℃ water bath for 12 hours, adding 72g of n-butyl alcohol, stirring for 2 hours, adding 154.8g of TEOS, stirring for one day, carrying out suction filtration on a solid-liquid mixture in the four-neck flask, transferring the mixture into a reaction kettle, carrying out hydrothermal reaction in an oven for 24 hours, taking out the mixture for natural cooling, carrying out suction filtration and washing with deionized water until the mixture is neutral, placing the mixture into a crucible, drying the mixture in a drying oven at 70 ℃ overnight, taking out, grinding and calcining, controlling the temperature rise rate to be 1-2 ℃/min, the calcining temperature to be 550 ℃ and the calcining time to.

The hydrothermal reaction temperature in the step 1) is 40-140 ℃.

The step 2) of fully shaking and grinding specifically means shaking and grinding for 1 time every 5-30min, and shaking and grinding for 3-5 times in total.

In the step 2), the mass ratio of the gallium salt to the ordered mesoporous silica hard template is 1: 1.13-1:3.69, wherein the mass ratio of the zinc salt to the ordered mesoporous silica hard template is 1: 3.16-1:10.35.

The volume of the precursor in the step 2) accounts for 20-40% of the pore volume of the mesoporous silica.

The calcining temperature in the step 3) is 500-850 ℃, the heating rate is 1-3 ℃/min, and the calcining time is 2-10 h.

Wherein the calcining heating rate is 1-2 ℃/min, the calcining temperature is 550 ℃, and the calcining time is 6 h.

The concentration of the sodium hydroxide solution in the step 4) is 2-10M.

The invention provides a controllable synthetic ordered large mesoporous zinc gallate material and a preparation method thereof, and the material has good methylene blue degradation performance.

The method has the advantages that:

1) preparing mesoporous silicon oxide with larger hole wall connecting holes by a hydrothermal method, enabling a precursor to smoothly enter a pore channel by adopting a nano-casting method, and well copying after a template is etched to obtain ordered large mesoporous gallate;

2) the aperture of the zinc gallate material obtained by the invention can reach 10.7nm, the thickness of the hole wall is about 5nm, and the large aperture is beneficial to the transmission and diffusion of molecules; the specific surface area is as high as 138m²And/g, can provide more surface active sites.

3) The zinc gallate material prepared by the invention has good effect on degrading pollutants such as dye, for example, 99.3% of methylene blue is degraded in 50 minutes under the condition of ultraviolet light. In addition, the material of the invention also has better effect in the aspect of photocatalytic hydrogen production.

Drawings

FIG. 1 is a TEM image of the mesoporous zinc gallate material obtained in example 1;

FIG. 2 is a diagram showing the pore size distribution of the mesoporous zinc gallate material obtained in example 1;

FIG. 3 shows the property of the zinc pore gallate material obtained in example 1 on the degradation of methylene blue.

Detailed Description

The invention relates to a method for synthesizing zinc gallate with ordered large mesopores and high specific surface area. The preparation method is that orderly silicon dioxide with hole walls and larger through holes is synthesized as a hard template to prepare the spinel zinc gallate with ordered and large mesopores. The synthesis method of the invention mainly comprises the steps of firstly synthesizing mesoporous silica with larger pore wall communicated pore channels, and removing the surfactant in the pore channels through high-temperature calcination, thereby obtaining rigid silica as a hard template to prepare the ordered mesoporous zinc gallate. The invention can controllably synthesize the ordered spinel zinc gallate with different apertures and specific surface areas through different hydrothermal temperatures during template preparation, has high controllability and repeatability, and is widely applied to the fields of gas-sensitive materials, photocatalytic degradation, carbon dioxide catalytic reduction and the like.

The technical scheme of the invention is as follows:

a process for preparing the high-specific-surface-area ordered large-mesopore spinel zinc gallate features that the calcined mesopore silicon dioxide is used as hard template. The method comprises the following steps:

1) preparation of a silica template: adding surfactant P₁₂₃Mixing with water and hydrochloric acid, stirring to obtain mixture P₁₂₃Dissolving completely, then sequentially adding a certain amount of tetraethoxysilane and n-butanol, continuously stirring, performing suction filtration, putting into a polytetrafluoroethylene lining, performing hydrothermal reaction, then performing suction filtration and washing by using deionized water to be neutral, drying in a forced air drying oven, and grinding and calcining to obtain white powder, namely the ordered mesoporous silica template; '

2) The specific steps in the implementation mode of the invention are as follows: will P₁₂₃72g, 2600mL deionized water and 120mL concentrated hydrochloric acid (37%), mixing at room temperature, and stirring until completely dissolved; then stirring in a water bath at 35 ℃ for 12 hours; adding 72g of n-butanol, stirring for 2 hours, then adding 154.8g of TEOS, and stirring for 24 hours; then filtering and transferring, carrying out suction filtration on the solid-liquid mixture in the four-neck flask, transferring into a reaction kettle, and carrying out hydrothermal reaction in an oven for 24 hours; then taking out and naturally cooling, and carrying out suction filtration and washing until the solution is neutral; putting into a crucible, and drying in a drying oven at 70 ℃ overnight; taking out, grinding and calcining;

3) the surfactant is mainly removed by high-temperature calcination, the specific calcination procedure is 1-2 ℃/min, the calcination temperature is 550 ℃, and the calcination time is 6 h;

4) taking the prepared ordered mesoporous silicon oxide as a hard template, heating and melting gallium salt and zinc salt serving as precursors by the method in the step 2), mixing with the template, shaking up, grinding and calcining;

the gallium salt is x hydrated gallium nitrate, and the zinc salt is zinc nitrate hexahydrate;