阅读说明：本技术 δ-MnO2负载氧化石墨烯与Ag-Gd复合型催化剂的方法和应用 (δ-MnO2Method and application of loaded graphene oxide and Ag-Gd composite catalyst ) 是由 叶青 董宁 肖阳 张丹 于 2021-08-11 设计创作，主要内容包括：本发明提供了δ-MnO-(2)负载氧化氧化石墨烯Ag-Gd复合型催化剂的方法和应用。采用溶胶-凝胶法制备δ-MnO-(2),然后将氧化石墨烯与Ag(银)-Gd(钆)复合金属采用离子交换法负载到δ-MnO-(2)上,最后得到Ag-Gd/GO/δ-MnO-(2)催化剂。其中GO的负载量为≤3.0wt％,Ag负载量≤1.0wt％,Gd负载量≤0.1wt％。本发明所制催化剂在温度(100～250℃)、空速(60,000～240,000h～(-1))的情况下,对高浓度乙酸乙酯(1000～3000ppm)具有良好的催化消除效果(乙酸乙酯转化率95-99％)和稳定性(反应50h活性不变)。本发明催化剂制备原料廉价和制备过程简单。(The invention provides delta-MnO 2 A method for loading a graphene oxide Ag-Gd composite catalyst and application. Preparation of delta-MnO by sol-gel method 2 Then loading graphene oxide and Ag (silver) -Gd (gadolinium) composite metal to delta-MnO by adopting an ion exchange method 2 Finally obtaining Ag-Gd/GO/delta-MnO 2 A catalyst. Wherein the load capacity of GO is less than or equal to 3.0 wt%, the load capacity of Ag is less than or equal to 1.0 wt%, and the load capacity of Gd is less than or equal to 0.1 wt%. The catalyst prepared by the invention has the advantages of temperature (100-250 ℃) and space velocity (60,000-240,000 h) ‑1 ) Under the condition of (1), the catalyst has good catalytic elimination effect (the conversion rate of the ethyl acetate is 95-99%) and stability (the activity is unchanged after 50 hours of reaction) on high-concentration ethyl acetate (1000-3000 ppm). The catalyst of the invention has cheap raw materials and simple preparation process。)

1.δ-MnO₂Load graphene oxide and Ag-The method for preparing the Gd composite catalyst is characterized by comprising the following steps:

delta-MnO in sol-gel process₂Preparation of the support

50mL 0.38mol/L KMnO₄Adding the solution into 20mL1.4 mol/L glucose solution, stirring for 30s to form brown gel, discharging water generated in the gel synthesis process every 20 minutes, drying at 110 ℃ for 24h to obtain brown xerogel, and calcining the xerogel at 400 ℃ for 2h to obtain delta-MnO₂A grey black gray; washing with water and drying at 110 deg.C to obtain pure delta-MnO₂；

Ag-Gd/GO/δ-MnO₂Catalyst preparation

Dispersing 0.01-0.09g of single-layer graphene oxide powder in 50-100mL of deionized water, and then carrying out ultrasonic treatment for 6h to obtain a single-layer graphene oxide GO suspension solution; mixing 0.017-0.054g AgNO₃And 0.86-8.61mg of Gd (NO)₃)₃·6H₂Adding O into 50-100mL of deionized water to form a uniform Ag and Gd mixed solution, wherein the mass ratio of Ag to Gd is 1: 0.03-0.1; adding 0.012-0.045g of polyvinyl alcohol and 50-100mL of single-layer graphene oxide GO suspension solution prepared above into the Ag and Gd mixed solution under the condition of ice-water bath, stirring for 30 minutes, and injecting 2.0g/L NaBH₄The solution forms a dark brown suspension, and the Ag-Gd/GO suspension is obtained after further stirring for 1 h; then 1-3g of delta-MnO₂Adding the mixture into the Ag-Gd/GO suspension liquid with the volume of 50-200mL, and continuously stirring for 6 hours; washing the sample twice by using deionized water and absolute ethyl alcohol, and then drying the sample in an oven at the temperature of 80-120 ℃ for 12-24 h; finally, calcining the obtained sample in a muffle furnace at the temperature of 400-450 ℃ for 2-4h at the heating rate of 3-5 ℃/min to obtain the sample of Ag-Gd/GO/delta-MnO₂。

2. Use of the catalyst prepared by the process of claim 1 for elimination of ethyl acetate, wherein: putting the catalyst into a continuous flow fixed bed device, and introducing ethyl acetate containing 1000-3000ppm and 20 vol.% of O₂And N₂Reacting in the mixed gas as the balance gas; the reaction pressure is normal pressure 1atm, the reaction space velocity is space velocity 60,000-240,000h^-1The reaction temperature is 100-250 ℃.

Technical Field

The invention relates to delta-MnO for catalyzing and eliminating ethyl acetate₂A preparation method of a loaded graphene oxide Gd-Ag composite catalyst and application of the loaded graphene oxide Gd-Ag composite catalyst in selective catalytic elimination of ethyl acetate.

Background

The volatile esters have various types and wide distribution, and bring great harm to the health of human beings, the growth of animals and plants and the ecological environment. Most of the esters are toxic, some of them are carcinogenic, and the influence on human health is mainly manifested as irritation to eyes, nose, throat, head, neck and facial skin, etc., which may cause dizziness, headache, neurasthenia and inflammations of skin, mucous membrane, etc. Liver and kidney function may also be compromised when the concentration of esters is high.

δ-MnO₂Is a water-containing mineral material with a two-dimensional layered structure, and is a manganese oxide mineral commonly existing in soil, sediments and ocean manganese nodules. The microporous characteristic of birnessite and the abundant content in ocean make it be used as a high-efficiency adsorbent or heterogeneous catalyst, including heavy metal adsorption, oxidation of ethanol and carbon monoxide, reduction of nitric oxide, olefin hydrogenation, decomposition of organic sulfide and the like. Graphene oxide, a powerful sp2 hybridized two-dimensional 2D carbon sheet, has attracted extensive attention in the field of catalysis due to its unique 2D structure, high surface area and good electron transport capability₂Noble metal-loaded ethyl acetate is catalyzed and oxidized, but researches on graphene oxide and Ag-Gd-loaded ethyl acetate are not many. Therefore, the delta-MnO is prepared by adopting a sol-gel method₂Preparing Ag-Gd/GO/delta-MnO by an ion exchange method₂The catalyst can catalyze the ethyl acetate at a lower temperature and shows better activity and stability.

The implementation of this project resulted in: national science foundation project (number: 21277008; 20777005); the subsidization of the national emphasis research and development program (No.2017YFC0209905) is also the research content of these projects.

Disclosure of Invention

The invention relates to delta-MnO for catalyzing and eliminating ethyl acetate₂A preparation method of a loaded graphene oxide Ag-Gd composite catalyst and application of the catalyst in selective catalytic elimination of ethyl acetate. The provided catalyst can effectively eliminate high temperature at the reaction temperature of 100 ℃ and 250 DEG CThe concentration of ethyl acetate is 1000-3000ppm, and the catalyst has good catalytic elimination effect, and the conversion rate of ethyl acetate is 95-99%. The catalyst can obviously enhance the electron transfer efficiency between Ag-Gd-Mn after being doped with graphene, thereby enhancing the catalytic efficiency and reducing the conversion temperature, and has the advantages of simple preparation process, low cost, good stability and the like.

The invention provides delta-MnO for catalyzing and eliminating ethyl acetate₂The preparation method of the loaded graphene oxide Ag-Gd composite catalyst comprises the following steps:

1. delta-MnO in sol-gel process₂Preparation of the support

50mL 0.38mol/L KMnO₄Adding the solution into 20mL1.4 mol/L glucose solution, stirring for 30s to form brown gel, discharging water generated in the gel synthesis process every 20 minutes, drying at 110 ℃ for 24h to obtain brown xerogel, and calcining the xerogel at 400 ℃ for 2h to obtain delta-MnO₂A grey black gray. Washing with water and drying at 110 deg.C to obtain pure delta-MnO₂。

2、Ag-Gd/GO/δ-MnO₂Catalyst preparation

Dispersing 0.01-0.09g of monolayer graphene oxide powder in 50-100mL of deionized water, and then carrying out ultrasonic treatment for 6h to obtain a monolayer GO suspension solution. Mixing 0.017-0.054g AgNO₃And 0.86-8.61mg of Gd (NO)₃)₃·6H₂And adding O into 50-100mL of deionized water to form a uniform Ag and Gd mixed solution. Under the condition of ice-water bath, 0.012-0.045g of polyvinyl alcohol and 50-100mL of graphene oxide suspension solution prepared above are added into the Ag and Gd mixed solution and stirred for 30 minutes, and then 2.0g/L of NaBH is injected₄The solution formed a dark brown suspension which after further stirring for 1 hour gave an Ag-Gd/GO suspension. Then 1-3g of delta-MnO₂Add to the above 50-200mL Ag-Gd/GO suspension and continue stirring for 6 hours. The sample was washed twice with deionized water and absolute ethanol and then dried in an oven at 80-120 ℃ for 12-24 hours. Finally, calcining the obtained sample in a muffle furnace at the temperature of 400-450 ℃ for 2-4h at the heating rate of 3-5 ℃/min to obtain the sample of Ag-Gd/GO/delta-MnO₂。

3. The inventionCatalyst under the reaction pressure of normal pressure 1atm and the space velocity of 60,000h^-1-240,000h^-1、20vol.％O₂The ethyl acetate concentration is 1000-3000ppm and the equilibrium gas is N₂Under the condition, the catalyst has high catalytic activity on ethyl acetate within the temperature range of 100 ℃ and 250 ℃, and the conversion rate is 95-99%. (ii) a At the reaction pressure of normal pressure 1atm and the space velocity of 60,000h^-1-240,000h^-1、20vol.％O₂The ethyl acetate concentration is 1000-3000ppm and the equilibrium gas is N₂Under the condition, the load type Ag-Gd/delta-MnO is investigated₂And Ag-Gd/GO/delta-MnO₂The catalyst, 120-. The catalytic activity still shows high stability at the temperature range studied.

Drawings

FIG. 1 shows Ag-Gd/delta-MnO prepared in examples 1, 2, 3 and 4 of the present invention₂、Ag-Gd/GO/δ-MnO₂-I、Ag-Gd/GO/δ-MnO₂-II and Ag-Gd/GO/delta-MnO₂-XRD pattern of III catalyst.

FIG. 2 shows Ag-Gd/delta-MnO prepared in examples 1, 2, 3 and 4 of the present invention₂、Ag-Gd/GO/δ-MnO₂-I、Ag-Gd/GO/δ-MnO₂-II and Ag-Gd/GO/delta-MnO₂N of-III catalyst₂Adsorption/desorption scheme.

FIG. 3 shows Ag-Gd/delta-MnO prepared in examples 1, 2, 3 and 4 of the present invention₂、Ag-Gd/GO/δ-MnO₂-I、Ag-Gd/GO/δ-MnO₂-II and Ag-Gd/GO/delta-MnO₂-III catalytic oxidation ethyl acetate activity diagram.

FIG. 4 shows Ag-Gd/delta-MnO prepared in examples 1, 2, 3 and 4 of the present invention₂、Ag-Gd/GO/δ-MnO₂-I、Ag-Gd/GO/δ-MnO₂-II and Ag-Gd/GO/delta-MnO₂Stability of the-III catalyst at 160 ℃ for 50 hours.

Detailed Description

Example 1

1. delta-MnO in sol-gel process₂Preparation of the support

50mL 0.38mol/L KMnO₄The solution was added to 20ml of 1.4 mol/L glucose solution and stirred for 30s to form a brown colorGel, discharging water generated in the gel synthesis process every 20 minutes, drying at 110 ℃ for 24 hours to obtain brown xerogel, and calcining the xerogel at 400 ℃ for 2 hours to obtain delta-MnO₂A grey black gray. Washing with water and drying at 110 deg.C to obtain pure delta-MnO₂。

2、Ag-Gd/δ-MnO₂Catalyst preparation

0.0085g of AgNO₃And 0.86mg of Gd (NO)₃)₃·6H₂O was added to 50mL of deionized water to form a homogeneous Ag and Gd solution. Under the condition of ice-water bath, 0.012g of polyvinyl alcohol is added into the mixed solution and stirred for 30 minutes, and then 2.0g/L of NaBH is injected₄The solution formed a dark brown suspension which after further stirring for 1 hour gave an Ag-Gd suspension. Then 1g of delta-MnO₂Add to the above 50mL of Ag-Gd suspension and continue stirring for 6 hours. The sample was washed twice with deionized water and absolute ethanol and then dried in an oven at 80 ℃ for 12 hours. Finally, the obtained sample is calcined in a muffle furnace for 2h at the heating rate of 3-5 ℃/min for 400 h, and the obtained sample is Ag-Gd/delta-MnO₂。

3. The catalyst of the invention has the reaction pressure of 1atm under normal pressure and the space velocity of 60,000h^-1、20vol.％O₂Ethyl acetate concentration 1000ppm and equilibrium gas N₂Under the condition, the catalyst has high catalytic activity within the temperature range of 100 ℃ and 250 ℃, and the conversion rate of ethyl acetate is 98 percent; at the reaction pressure of normal pressure 1atm and the space velocity of 60,000h^-1、20vol.％O₂Ethyl acetate concentration 1000ppm and equilibrium gas N₂Under the condition, the Ag-Gd/delta-MnO is investigated at 160 DEG C₂Conversion of ethyl acetate over 50 hours for the sample. The catalytic activity still shows high stability at the temperatures studied.

Example 2

1. delta-MnO in sol-gel process₂Preparation of the support

50mL 0.38mol/L KMnO₄Adding the solution into 20ml1.4 mol/L glucose solution, stirring for 30s to form brown gel, discharging water every 20 min during gel synthesis, and drying at 110 deg.C for 24 hr to obtain brown xerogel, xerogelCalcining at 400 ℃ for 2h to obtain delta-MnO₂A grey black gray. Washing with water and drying at 110 deg.C to obtain pure delta-MnO₂。

2、Ag-Gd/GO/δ-MnO₂Preparation of the catalyst

0.01g of monolayer graphene oxide powder was dispersed in 50ml of deionized water and then sonicated for 6h to obtain a monolayer GO suspension. 0.017g of AgNO₃And 0.86mg of Gd (NO)₃)₃·6H₂O was added to 50ml of deionized water to form a homogeneous Ag and Gd mixed solution. Under the condition of ice-water bath, 0.012g of polyvinyl alcohol and 50mL of graphene oxide suspension solution prepared above are added into the Ag and Gd mixed solution, stirred for 30 minutes, and then 2.0g/L of NaBH is injected₄The solution formed a dark brown suspension which after further stirring for 1 hour gave an Ag-Gd/GO suspension. Then 1g of delta-MnO₂Add to 100mL of Ag-Gd/GO suspension above and continue stirring for 6 hours. The sample was washed twice with deionized water and absolute ethanol and then dried in an oven at 100 ℃ for 12 hours. Finally, the obtained sample is calcined in a muffle furnace at the temperature of 420 ℃ for 2h, the heating rate is 3 ℃/min, and the obtained sample is Ag-Gd/GO/delta-MnO₂-I。

3. The catalyst of the invention has the reaction pressure of 1atm under normal pressure and the space velocity of 120,000h^-1、20vol.％O₂The concentration of ethyl acetate is 1500ppm and the equilibrium gas is N₂Under the condition, the catalyst has high catalytic activity within the temperature range of 100 ℃ and 200 ℃, and the conversion rate of ethyl acetate is 98 percent; at the reaction pressure of normal pressure 1atm and the space velocity of 120,000h^-1、20vol.％O₂The concentration of ethyl acetate is 1500ppm and the equilibrium gas is N₂Under the condition, the Ag-Gd/GO/delta-MnO is investigated at 160 DEG C₂I conversion of the sample in 50 hours of ethyl acetate. The catalytic activity still shows high stability at the temperatures studied.

Example 3

1. delta-MnO in sol-gel process₂Preparation of the support

50mL 0.38mol/L KMnO₄Adding the solution into 20ml1.4 mol/L glucose solution, stirring for 30s to form brown gel, and mixing every 20 min during gel synthesisDischarging the generated water, drying at 110 ℃ for 24h to obtain brown xerogel, and calcining the xerogel at 400 ℃ for 2h to obtain delta-MnO₂A grey black gray. Washing with water and drying at 110 deg.C to obtain pure delta-MnO₂。

2、Ag-Gd/GO/δ-MnO₂Preparation of the catalyst

0.04g of single-layer graphene oxide powder was dispersed in 70ml of deionized water and then sonicated for 6h to obtain a single-layer GO suspension. 0.034g of AgNO₃And 0.344mg of Gd (NO)₃)₃·6H₂O was added to 50ml of deionized water to form a homogeneous Ag and Gd mixed solution. Under the condition of ice-water bath, 0.026g of polyvinyl alcohol and 70mL of graphene oxide suspension solution prepared above are added into the Ag and Gd mixed solution, stirred for 30 minutes, and then 2.0g/L of NaBH is injected₄The solution formed a dark brown suspension which after further stirring for 1 hour gave an Ag-Gd/GO suspension. Then 2g of delta-MnO₂Add to the above 120mL Ag-Gd/GO suspension and continue stirring for 6 hours. The sample was washed twice with deionized water and absolute ethanol and then dried in an oven at 120 ℃ for 12 hours. Finally, the obtained sample is calcined in a muffle furnace at 430 ℃ for 4h, the heating rate is 4 ℃/min, and the obtained sample is Ag-Gd/GO/delta-MnO₂-II。

3. The catalyst of the invention has the reaction pressure of 1atm under normal pressure and the space velocity of 180,000 h^-1、20vol.％O₂Ethyl acetate concentration 2000ppm and equilibrium gas N₂Under the condition, the catalyst has high catalytic activity within the temperature range of 100 ℃ and 180 ℃, and the conversion rate of ethyl acetate is 98.9 percent; at the reaction pressure of normal pressure 1atm and the space velocity of 120,000h^-1、20vol.％O₂Ethyl acetate concentration 2000ppm and equilibrium gas N₂Under the condition, the Ag-Gd/GO/delta-MnO is investigated at 160 DEG C₂II conversion of the sample of ethyl acetate in 50 hours. The catalytic activity still shows high stability at the temperatures studied.

Example 4

1. delta-MnO in sol-gel process₂Preparation of the support

50mL 0.38mol/L KMnO₄The solution was added to 20ml L1.4 mol/L glucoseStirring for 30s in glucose solution to form brown gel, discharging water every 20 min during gel synthesis, drying at 110 deg.C for 24 hr to obtain brown xerogel, and calcining at 400 deg.C for 2 hr to obtain delta-MnO₂A grey black gray. Washing with water and drying at 110 deg.C to obtain pure delta-MnO₂。

2、Ag-Gd/GO/δ-MnO₂Preparation of the-III catalyst

0.09g of single layer graphene oxide powder was dispersed in 100ml of ionized water and then sonicated for 6h to obtain a single layer GO suspension. 0.054g of AgNO₃And 8.61mg of Gd (NO)₃)₃·6H₂O was added to 100mL of deionized water to form a homogeneous Ag and Gd solution. Under the condition of ice-water bath, 0.045g of polyvinyl alcohol and 100mL of graphene oxide suspension solution prepared above are added into the Ag and Gd mixed solution, stirred for 30 minutes, and then 2.0g/L of NaBH is injected₄The solution formed a dark brown suspension which after further stirring for 1 hour gave an Ag-Gd/GO suspension. Then 3g of delta-MnO₂Add to 200mL of Ag-Gd/GO suspension above and continue stirring for 6 hours. The sample was washed twice with deionized water and absolute ethanol and then dried in an oven at 120 ℃ for 24 hours. Finally, the obtained sample is calcined in a muffle furnace at 430 ℃ for 3 hours at a heating rate of 5 ℃/min, and the obtained sample is Ag-Gd/GO/delta-MnO₂-III。

3. The catalyst of the invention has the reaction pressure of 1atm under normal pressure and the space velocity of 240,000h^-1、20vol.％O₂Ethyl acetate concentration 3000ppm and equilibrium gas N₂Under the condition, the catalyst has high catalytic activity within the temperature range of 100 ℃ and 190 ℃, and the conversion rate of ethyl acetate is 99 percent; under the reaction pressure of normal pressure 1atm and the space velocity of 240,000h^-1、20vol.％O₂Ethyl acetate concentration 3000ppm and equilibrium gas N₂Under the condition, the Ag-Gd/GO/delta-MnO is investigated at 160 DEG C₂-conversion of ethyl acetate in 50 hours for sample III. The catalytic activity still shows high stability at the temperatures studied.