CN108187729B

CN108187729B - Composite catalyst film and preparation method and application thereof

Info

Publication number: CN108187729B
Application number: CN201810036905.2A
Authority: CN
Inventors: 王白银; 陈为; 孙予罕; 马翠杰; 张佳舟; 南贵珍
Original assignee: Shanghai Advanced Research Institute of CAS
Current assignee: Shanghai Advanced Research Institute of CAS
Priority date: 2018-01-15
Filing date: 2018-01-15
Publication date: 2021-03-12
Anticipated expiration: 2038-01-15
Also published as: CN108187729A

Abstract

The invention provides a preparation method of a composite catalyst film, which comprises the following steps: mixing metal acid ester and alcohol to prepare a precursor; coating a matrix with a porous material solution; coating the precursor; calcining to obtain the composite catalyst film. The preparation method and the catalyst obtained by the preparation method disclosed by the invention are used for photocatalytic conversion of carbon dioxide, have higher photoactivity, and can generate products such as methanol, ethanol and the like with high selectivity.

Description

Composite catalyst film and preparation method and application thereof

Technical Field

The invention relates to a catalyst, a preparation method and application thereof, in particular to a composite catalyst film, and a preparation method and application thereof.

Background

Due to the gradual increase of the greenhouse effect, people have more and more intensive research on the catalytic conversion of carbon dioxide. Currently, widely studied carbon dioxide reduction methods mainly include catalytic hydrogenation reduction, photocatalytic reduction, thermochemical reduction, biological reduction, and the like. Wherein the thermochemical reduction has higher requirements on reaction equipment; the photocatalytic reduction of carbon dioxide is more attractive from the viewpoint of clean and sustainable solar energy utilization. Unlike other forms of carbon dioxide conversion processes, photocatalytic reduction can directly utilize sunlight to induce the reduction of carbon dioxide. Under the irradiation of sunlight, the photocatalyst can convert carbon dioxide into available fuels and chemical substances, and has great potential in solving the problems of environment and energy.

The most studied photocatalysts are mainly metal oxides, among which titanium dioxide is taken as a representative. Titanium dioxide has the advantages of high photocatalytic activity, strong corrosion resistance, stable optical property, no toxicity, relatively low price and the like, so that the titanium dioxide is a photocatalyst applied more. The nano titanium dioxide can greatly shorten the time for a photon-generated carrier to migrate to the surface due to the reduction of the particle size, thereby reducing the recombination probability of an electron-hole in a bulk phase and hopefully improving the efficiency of photocatalytic reduction.

However, the single metal oxide also has the disadvantages of small specific surface area, low sunlight utilization rate and the like, and finding a photocatalyst with high catalytic activity and high selectivity for improving the conversion rate of carbon dioxide is a future development direction. The common methods at present are to modify metal oxides, including metal doping, non-metal doping, metal oxide compounding, organic matter compounding, etc., which can effectively reduce the particle size of the metal oxides and increase the specific surface area, thereby greatly improving the photocatalytic activity, while the low utilization rate of sunlight is still a problem to be solved.

Disclosure of Invention

In view of the above disadvantages of the prior art, the present invention is directed to a composite catalyst thin film, a method for preparing the same, and a use of the same, which are used to solve the problems of low catalytic conversion efficiency and poor selectivity of carbon dioxide in the prior art.

To achieve the above objects and other related objects, the present invention is achieved by the following technical solutions.

The invention provides a preparation method of a composite catalyst film, which comprises the following steps:

1) mixing metal acid ester and alcohol to prepare a precursor;

2) coating a matrix with a porous material solution;

3) coating the precursor;

4) calcining to obtain the composite catalyst film.

Preferably, in step 1), the metal acid ester is one or more selected from the group consisting of tetraethyl titanate, tetrabutyl zirconate, molybdate ester, and aluminate ester.

Preferably, in step 1), the alcohol is one or more selected from methanol, ethanol, propanol and isopropanol.

Preferably, in the step 1), the mass ratio of the metal acid ester to the alcohol is (1.5-20): 40.

preferably, in step 1), the mixing is carried out under an inert atmosphere. The inert atmosphere comprises one or more of nitrogen, argon and helium. Because the raw material component of the metal acid ester is unstable and is easy to react with substances in the air to generate chemical change, the inert atmosphere is adopted for protection during mixing in the application.

Preferably, in step 1), mixing is performed using ultrasound.

Preferably, in the step 2), the porous material is one or more selected from the group consisting of an ETS-10 molecular sieve, a ZSM-5 molecular sieve, a SAPO-34 molecular sieve and an MCM-68 molecular sieve.

Preferably, in step 2), the solvent of the solution of the porous material is ethylene glycol.

Preferably, in the step 2), the concentration of the porous material solution is 1 wt% to 5 wt%. More preferably, in the step 2), the concentration of the porous material solution is 3 wt% to 5 wt%.

Preferably, in step 2), the substrate is a glass plate.

Preferably, the volume ratio of the precursor to the porous material solution is (1-7): 10.

preferably, the coating in step 2) and step 3) is performed by spin coating. More preferably, the spin coating rate is 1000 to 9000 r/min.

Preferably, in the step 4), the calcining temperature is 400-500 ℃.

Preferably, in step 4), the calcination time is not less than 0.5 hour.

The invention also provides a composite catalyst film prepared by the method.

The invention also provides application of the composite catalyst film in the photocatalytic reaction and the photoelectrocatalysis reaction of carbon dioxide.

According to the method and the application of the composite catalyst film provided by the invention, the single metal oxide nanoparticles are modified to prepare the composite system film of the metal oxide nanoparticles and the porous material, so that the carbon dioxide adsorption performance of the composite system can be improved, the utilization rate of sunlight is increased, the surface active sites and the contact area of the uniformly dispersed film can be greatly increased, and the photocatalytic activity of carbon dioxide is further effectively improved. The process is simple to operate, and the prepared catalyst film has good photocatalytic activity, high selectivity, good reproducibility and high stability. The catalyst can be applied to the processes of photocatalytic conversion and photoelectric catalytic conversion of carbon dioxide, particularly in the process of photocatalytic conversion of carbon dioxide, can greatly improve the generation rate of methanol and ethanol, has high selectivity, can solve the problems of the prior art, and has good application prospect.

Drawings

FIG. 1 is a TEM image of a composite catalyst thin film in example 6 of the present invention.

FIG. 2 shows an XPS plot of a composite catalyst thin film in example 6 of the present invention.

FIG. 3 is a schematic structural diagram of a carbon dioxide photocatalytic reaction apparatus according to an embodiment of the present invention.

Wherein the reference numerals in fig. 3 are as follows:

1 carbon dioxide gas supply device

2 steam mixing device

3 carbon dioxide light reaction device

4 carbon dioxide reaction product detection device

11 carbon dioxide gas storage unit

12 gas flowmeter

21 water container

22 water bath pot

211 inlet port

212 outlet port

31 reactor

32 catalyst carrier

33 light source

311 inlet

312 outlet

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

Before the present embodiments are further described, it is to be understood that the scope of the invention is not limited to the particular embodiments described below; it is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the respective manufacturers.

When numerical ranges are given in the examples, it is understood that both endpoints of each of the numerical ranges and any value therebetween can be selected unless the invention otherwise indicated. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, and materials used in the examples, any methods, devices, and materials similar or equivalent to those described in the examples may be used in the practice of the invention in addition to the specific methods, devices, and materials used in the examples, in keeping with the knowledge of one skilled in the art and with the description of the invention.

Example 1

Weighing high-purity tetraethyl titanate and isopropanol in a glove box, wherein the mass ratio of the tetraethyl titanate to the isopropanol is 1.5:40, ultrasonically mixing for 10min in a nitrogen atmosphere to form a precursor, subpackaging in small bottles, and taking out for later use. 0.05g of molecular sieve ETS-10 is added into 1.5g of ethylene glycol, and ultrasonic mixing is carried out for 30min at room temperature to prepare a molecular sieve solution. Putting a cleaned transparent glass sheet in the center of a sucker of a spin coater, spin-coating 200 mu L of porous material solution by using an injector, adjusting to a certain rotating speed, spin-coating at a rotating speed of 1000r/min for 20s, then spin-coating at a high rotating speed of 3000r/min for 30s, and repeating for 3-4 times to obtain a molecular sieve film with proper thickness; then 100 μ L of the precursor is taken and spun on the molecular sieve film at the same rotating speed. And then taking out the spin-coated glass sheet, standing at room temperature for about 10min, placing the glass sheet into a muffle furnace, carrying out temperature programming calcination in the air atmosphere, heating to 450 ℃ at a heating rate of 2 ℃/min, keeping the temperature for 60min, and naturally cooling to room temperature to obtain the titanium dioxide and molecular sieve composite catalyst film. The catalyst is used for the photocatalytic conversion of carbon dioxide, has higher photoactivity, and can generate products such as methanol, ethanol and the like with high selectivity.

Example 2

Weighing high-purity tetraethyl titanate and isopropanol in a glove box, wherein the mass ratio of the tetraethyl titanate to the isopropanol is 20:40, ultrasonically mixing for 90min in a nitrogen atmosphere to form a precursor, subpackaging in small bottles, and taking out for later use. 0.05g of ZSM-5 molecular sieve is added into 1.5g of ethylene glycol, and ultrasonic mixing is carried out for 30min at room temperature to prepare a molecular sieve solution. Putting a cleaned transparent glass sheet in the center of a sucker of a spin coater, spin-coating 200 mu L of porous material solution by using an injector, adjusting to a certain rotating speed, spin-coating at a rotating speed of 1500r/min for 20s, then spin-coating at a high rotating speed of 9000r/min for 30s, and repeating for 3-4 times to obtain a molecular sieve film with proper thickness; and then 20 mu L of precursor is taken and is coated on the molecular sieve film in a spin mode at the same rotating speed. And then taking out the spin-coated glass sheet, standing at room temperature for about 10min, placing the glass sheet into a muffle furnace, carrying out temperature programming calcination in the air atmosphere, heating to 450 ℃ at the heating rate of 30 ℃/min, keeping the temperature for 180min, and naturally cooling to room temperature to obtain the titanium dioxide and molecular sieve composite catalyst film. The catalyst is used for the photocatalytic conversion of carbon dioxide, has higher photoactivity, and can generate products such as methanol, ethanol and the like with high selectivity.

Example 3

Weighing high-purity tetrabutyl zirconate and ethanol in a glove box, wherein the mass ratio of the tetrabutyl zirconate to the ethanol is 3.36:40, ultrasonically mixing for 30min in a nitrogen atmosphere to form a precursor, subpackaging in small bottles, and taking out for later use. 0.07g of SAPO-34 molecular sieve is added into 1.4g of ethylene glycol, and ultrasonic mixing is carried out for 30min at room temperature to prepare molecular sieve solution. Putting a cleaned transparent glass sheet in the center of a sucker of a spin coater, taking 200 mu L of porous material solution by using an injector, spin-coating at a certain rotating speed for 20s at 1500r/min, then spin-coating at a high rotating speed of 8000r/min for 30s, and repeating for 3-4 times to obtain a molecular sieve film with proper thickness; then 60 μ L of the precursor is taken and spun on the molecular sieve film at the same rotating speed. And then taking out the spin-coated glass sheet, standing at room temperature for about 10min, placing the glass sheet into a muffle furnace, carrying out temperature programming calcination in the air atmosphere, heating to 450 ℃ at the heating rate of 2 ℃/min, keeping the temperature for 120min, and naturally cooling to room temperature to obtain the zirconium dioxide and molecular sieve composite catalyst film. The catalyst is used for the photocatalytic conversion of carbon dioxide, has higher photoactivity, and can generate products such as methanol, ethanol and the like with high selectivity.

Example 4

Weighing high-purity molybdate and propanol in a glove box, wherein the mass ratio of the molybdate to the propanol is 3.36:40, ultrasonically mixing for 30min in a nitrogen atmosphere to form a precursor, subpackaging in small bottles, and taking out for later use. 0.07g of MCM-68 molecular sieve is added into 1.4g of ethylene glycol, and ultrasonic mixing is carried out for 30min at room temperature, so as to prepare molecular sieve solution. Putting a cleaned transparent glass sheet in the center of a sucker of a spin coater, taking 200 mu L of porous material solution by using an injector, spin-coating at a certain rotating speed for 20s at 1500r/min, then spin-coating at a high rotating speed of 8000r/min for 30s, and repeating for 3-4 times to obtain a molecular sieve film with proper thickness; then 100 μ L of the precursor is taken and spun on the molecular sieve film at the same rotating speed. And then taking out the spin-coated glass sheet, standing at room temperature for about 10min, placing the glass sheet into a muffle furnace, carrying out temperature programming calcination in the air atmosphere, heating to 450 ℃ at the heating rate of 2 ℃/min, keeping the temperature for 120min, and naturally cooling to room temperature to obtain the molybdenum dioxide and molecular sieve composite catalyst film. The catalyst is used for the photocatalytic conversion of carbon dioxide, has higher photoactivity, and can generate products such as methanol, ethanol and the like with high selectivity.

Example 5

Weighing high-purity aluminate and isopropanol in a glove box, wherein the mass ratio of the aluminate to the isopropanol is 2:40, ultrasonically mixing the aluminate and the isopropanol in a nitrogen atmosphere for 30min to form a precursor, subpackaging the precursor into small bottles, and taking out the small bottles for later use. 0.07g of ETS-10 molecular sieve is added into 1.4g of ethylene glycol, and ultrasonic mixing is carried out for 30min at room temperature to prepare a molecular sieve solution. Putting a cleaned transparent glass sheet in the center of a sucker of a spin coater, taking 200 mu L of porous material solution by using an injector, spin-coating at a certain rotating speed for 20s at 1500r/min, then spin-coating at a high rotating speed of 8000r/min for 30s, and repeating for 3-4 times to obtain a molecular sieve film with proper thickness; and then 140 mu L of mixed solution of aluminate and isopropanol is taken to be spin-coated on the molecular sieve film at the same rotating speed. And then taking out the spin-coated glass sheet, standing at room temperature for about 10min, placing the glass sheet into a muffle furnace, carrying out temperature programming calcination in the air atmosphere, heating to 450 ℃ at the heating rate of 2 ℃/min, keeping the temperature for 120min, and naturally cooling to room temperature to obtain the aluminum oxide and molecular sieve composite catalyst film. The catalyst is used for the photocatalytic conversion of carbon dioxide, has higher photoactivity, and can generate products such as methanol, ethanol and the like with high selectivity.

Example 6

Weighing high-purity tetraethyl titanate and isopropanol in a glove box, wherein the mass ratio of the tetraethyl titanate to the isopropanol is 2:40, ultrasonically mixing for 30min in a nitrogen atmosphere to form a precursor, subpackaging in small bottles, and taking out for later use. 0.07g of ETS-10 molecular sieve is added into 1.4g of ethylene glycol, and ultrasonic mixing is carried out for 30min at room temperature to prepare a molecular sieve solution. Putting a cleaned transparent glass sheet in the center of a sucker of a spin coater, taking 200 mu L of molecular sieve solution by using an injector, spin-coating at a certain rotating speed for 20s at 1500r/min, then spin-coating at a high rotating speed of 8000r/min for 30s, and repeating for 3-4 times to obtain a molecular sieve film with proper thickness; then 100 mul of tetraethyl titanate and isopropanol mixed solution is taken to be spin-coated on the molecular sieve film at the same rotating speed. And then taking out the spin-coated glass sheet, standing at room temperature for about 10min, placing the glass sheet into a muffle furnace, carrying out temperature programming calcination in the air atmosphere, heating to 450 ℃ at a heating rate of 2 ℃/min, keeping the temperature for 100min, and naturally cooling to room temperature to obtain the titanium dioxide and molecular sieve composite catalyst film. The catalyst is used for the photocatalytic conversion of carbon dioxide, has higher photoactivity, and can generate products such as methanol, ethanol and the like with high selectivity.

The composite catalyst film prepared in examples 1 to 6 is used in a photocatalytic reaction of carbon dioxide, and a specific reaction system is shown in fig. 3, and the reaction system includes a carbon dioxide gas supply device 1, a water vapor mixing device 2, a carbon dioxide photoreaction device 3, and a carbon dioxide reaction product detection device 4, which are sequentially in airflow communication.

As shown in fig. 3, the carbon dioxide gas supply device 1 in the figure comprises a carbon dioxide gas storage unit 11 and a gas flow meter 12; the water vapor mixing device 2 comprises a closed water containing container 21, a water bath 22 and a gas conduit, wherein the water containing container 21 is provided with an inlet 211 and an outlet 212, the carbon dioxide gas supply device 1 extends into water through the gas conduit and the inlet 211 of the water containing container, the water containing container 21 is placed in the water bath 22, and the outlet 212 of the water containing container is communicated with the carbon dioxide photoreaction device 3 through the gas conduit; the carbon dioxide photoreaction device 3 comprises a reactor 31, a catalyst bearing part 32 and a light source 33, wherein the reactor is provided with an inlet 311 and an outlet 312, the catalyst bearing part 32 is arranged in a cavity of the reactor 31, the light source 33 is arranged vertically above the catalyst bearing part 32, and effluent gas in the water vapor mixing device 2 flows into the catalyst bearing part 32 through a gas conduit and the inlet 311 of the carbon dioxide photoreaction device; the outlet gas flow in the carbon dioxide photoreaction device 3 enters the carbon dioxide reaction product detection device 4 through the outlet 312 via a gas conduit. In a preferred embodiment, the carbon dioxide light reaction device 3 further comprises a quartz window, and the window is convenient for the xenon lamp light to pass through.

First, the process is reversedHigh purity CO of reaction gas₂The flow rate of the reaction is 10ml/min, and the reaction solution enters a closed reaction system with water vapor after passing through a constant-temperature 60 ℃ water bath device. The reaction device is a quartz reactor and is provided with an air inlet, an air outlet and a quartz window, and the window is convenient for xenon lamp light to pass through. Introducing CO under the condition of illumination₂And the gas and the water vapor react on the surface of the composite catalyst film, and the product is directly connected to chromatographic analysis and detection through a gas outlet and a gas conduit.

The catalytic performance of the composite catalyst thin films of examples 1 to 6 is shown in the following table:

as can be seen from the above table: the catalyst prepared in the embodiment 1-6 has high ethanol generation rate and high ethanol selectivity.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. The application of the composite catalyst film in the photocatalytic reaction of carbon dioxide comprises the following steps:

1) mixing metal acid ester and alcohol to prepare a precursor;

2) coating a matrix with a porous material solution;

3) coating the precursor;

4) calcining to obtain the composite catalyst film;

wherein, the coating adopts a spin coating mode;

in the step 1), the metal acid ester is one or two selected from tetraethyl titanate and tetrabutyl zirconate;

in the step 2), the porous material is one or more selected from an ETS-10 molecular sieve, a ZSM-5 molecular sieve, a SAPO-34 molecular sieve and an MCM-68 molecular sieve.

2. The use according to claim 1, wherein in step 1), the alcohol is one or more selected from the group consisting of methanol, ethanol, propanol and isopropanol.

3. The use according to claim 1, wherein in the step 1), the mass ratio of the metal acid ester to the alcohol is (1.5-20): 40.

4. use according to claim 1, wherein in step 1) the mixing is carried out in an inert atmosphere.

5. Use according to claim 1, wherein in step 2) the solvent of the porous material solution is ethylene glycol.

6. The use according to claim 1, wherein in step 2), the concentration of the porous material solution is 1 to 5 wt.%.

7. The use according to claim 1, wherein the volume ratio of the precursor to the porous material solution is (1-7): 10.

8. the use according to claim 1, wherein in step 4), the calcination temperature is 400 to 500 ℃.