A method for the photocatalytic reduction of carbon dioxide by infrared light

Abstract

The present application relates to a kind of infrared photocatalytic reduction carbon dioxide method, belong to the technical field of reducing CO2 greenhouse effect.The photocatalyst is uniformly coated on the inner surface of transparent reactor, then deionized water is added in the transparent reactor, finally CO2 gas is used to purge to remove air in the transparent reactor;Xe lamp filtered out infrared light and infrared light with wavelength of 1.8 μm, 2.0 μm, 2.7 μm, 3.4 μm or 4.3 μm are used to irradiate the transparent reactor simultaneously, carbon dioxide reduction reaction is carried out, reaction temperature is 20-30 ℃, and reaction time is 0.5-6 h.In the method of the present application, infrared light with wavelength of 1.8 μm, 2.0 μm, 2.7 μm, 3.4 μm or 4.3 μm is applied to carbon dioxide reduction reaction, so that the conversion efficiency of carbon dioxide is improved.

Description

Technical Field

[0001] This invention relates to a method for infrared photocatalytic reduction of carbon dioxide, belonging to the field of technology for reducing the greenhouse effect of CO2. Background Technology

[0002] In the continuous development of modern industry, the overuse of fossil fuels has led to the massive emission of greenhouse gases such as CO2, further contributing to environmental problems such as the greenhouse effect. The important issues of recovering and reducing atmospheric CO2 and reducing greenhouse gas emissions have attracted high attention from the international community and become a research hotspot worldwide. Currently, carbon dioxide reduction technologies mainly include thermocatalysis, electrocatalysis, and photocatalysis. Traditional thermocatalysis is often carried out under high temperature (250-400℃) and high pressure (2-5MPa) conditions. Although the reaction efficiency is high, the reaction conditions are harsh and energy consumption is high. Compared with thermocatalysis, electrocatalysis has milder reaction conditions, but the electrocatalytic system still requires a large energy input, and the catalytic performance is greatly affected by the electrode materials and their interfaces, still suffering from low conversion efficiency and poor stability. Compared with thermocatalysis and electrocatalysis, photocatalysis has milder reaction conditions and lower energy consumption. However, on the other hand, most catalysts can only absorb about 47.7% of ultraviolet and visible light, which constitutes a limited light absorption range. Therefore, the light energy conversion efficiency of photocatalytic carbon dioxide reduction is not high. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a method for infrared photocatalytic reduction of carbon dioxide.

[0004] The technical solution of this invention is:

[0005] A method for infrared photocatalytic reduction of carbon dioxide, the method comprising the following steps:

[0006] The first step is to evenly coat the photocatalyst on the inner surface of the transparent reactor, then add deionized water into the transparent reactor, and finally use CO2 gas to purge the air in the transparent reactor.

[0007] The second step involves simultaneously irradiating a transparent reactor with an Xe lamp that filters out infrared light and infrared light with wavelengths of 1.8μm, 2.0μm, 2.7μm, 3.4μm, or 4.3μm to carry out a carbon dioxide reduction reaction. The reaction temperature is 20-30℃, and the reaction time is 0.5-6h.

[0008] In the first step, the photocatalyst is TiO2, ZnO, CdS, g-C3N4, graphene, metal-organic framework, TiO2 composite material, ZnO composite material, CdS composite material, g-C3N4 composite material, graphene composite material, or metal-organic framework composite material, preferably a ZnO composite material, specifically a ZnO / Au / Cu composite material. x O nanoparticles, x = 1-2;

[0009] In the first step, the transparent reactor is a quartz reactor or a glass reactor, and the pressure of the transparent reactor is 0.08-0.10 MPa;

[0010] In the second step, the method for filtering the infrared light in the Xe lamp is as follows: add an infrared filter at the outlet of the Xe lamp light source or add a square transparent quartz container filled with water at the outlet of the Xe lamp light source. The square transparent quartz container has a thickness of 3-6 cm in the light path direction.

[0011] In the second step, the power of the Xe lamp is 100-400W;

[0012] In the second step, the infrared light with wavelengths of 1.8μm, 2.0μm, 2.7μm, 3.4μm or 4.3μm is an LED infrared lamp with a power of 0.1-100W;

[0013] In the second step, when using Xe lamps that filter out infrared light and LED infrared lamps to simultaneously irradiate the transparent reactor, the Xe lamps that filter out infrared light need to irradiate the photocatalyst; the angle between the beam of the Xe lamp and the beam of the LED infrared lamp is 0-90°.

[0014] Through the above technical solution, the present invention achieves the following beneficial effects:

[0015] In the method of the present invention, infrared light with wavelengths of 1.8 μm, 2.0 μm, 2.7 μm, 3.4 μm or 4.3 μm is applied to the carbon dioxide reduction reaction, thereby improving the conversion efficiency of carbon dioxide. Detailed Implementation

[0016] The present invention will be described in detail below through embodiments.

[0017] Example 1

[0018] A method for infrared photocatalytic reduction of carbon dioxide, the method comprising the following steps:

[0019] (1) Add 50 mg ZnO nanoparticles, 3 mL methanol, 7 mL deionized water, and 25 μL chloroauric acid tetrahydrate (25 g / L) solution to a transparent reaction flask. Sonicate for 10 minutes and stir thoroughly. Seal the reaction flask and purge with argon gas for 10 minutes to remove air. Turn on a 300 W Xe lamp and control the light intensity to 100 mW / cm². 2 After 3 hours of illumination, 10 mL of 0.02 mol / L copper nitrate solution was added to the above mixed solution. The mixture was then added to a polytetrafluoroethylene (PTFE) reactor and reacted in an oven at 200°C for 12 hours. After the reaction, the resulting suspension was washed twice each with ethanol and water by centrifugation to remove organic and inorganic impurities. The resulting solid was dried to obtain ZnO / Au / Cu. x O nanoparticles.

[0020] (2) Add 5mg ZnO / Au / Cu x O nanoparticles are uniformly coated on one side of a transparent reactor, with that side facing the light source. 200 μL of deionized water is added to the reactor, the reactor is sealed, and CO2 gas is purged for 5 minutes to remove air from the reactor. The pressure inside the reactor is 0.08 MPa.

[0021] (3) An LED infrared light source with a power of 0.4W and an infrared wavelength of 2.0μm was selected. A Xe lamp with a power of 150W was selected, and a square transparent quartz container filled with water was placed at the outlet of the Xe lamp to filter out the infrared light from the Xe lamp. The container was 5cm thick along the light path. The Xe lamp and the LED infrared lamp were turned on simultaneously and the light was applied for 2 hours to complete the photocatalytic carbon dioxide reduction reaction.

[0022] The specific contents of the reduction reaction products CH4 and CO were determined to be 2.0 μmol and 6.0 μmol, respectively, using a GC9790Plus gas chromatograph. Based on these contents, the generation rates of CH4 and CO were found to be 200 μmol / g / h and 600 μmol / g / h, respectively.

[0023] Example 2

[0024] The difference from Example 1 is that the wavelength of the LED infrared light source used is 1.8 μm;

[0025] The specific contents of the reduction reaction products CH4 and CO were determined to be 1.5 μmol and 12.5 μmol, respectively, using a GC9790Plus gas chromatograph. Based on these contents, the generation rates of CH4 and CO were found to be 150 μmol / g / h and 1250 μmol / g / h, respectively.

[0026] Example 3

[0027] The difference from Example 1 is that the wavelength of the LED infrared light source used is 2.7 μm;

[0028] The specific contents of the reduction reaction products CH4 and CO were determined to be 1.4 μmol and 3.2 μmol, respectively, using a GC9790Plus gas chromatograph. Based on these contents, the generation rates of CH4 and CO were found to be 140 μmol / g / h and 320 μmol / g / h, respectively.

[0029] Example 4

[0030] The difference from Example 1 is that the wavelength of the LED infrared light source used is 3.4 μm;

[0031] The specific contents of the reduction reaction products CH4 and CO were determined to be 3.6 μmol and 4.2 μmol, respectively, using a GC9790Plus gas chromatograph. Based on these contents, the generation rates of CH4 and CO were found to be 360 ​​μmol / g / h and 420 μmol / g / h, respectively.

[0032] Example 5

[0033] The difference from Example 1 is that the wavelength of the LED infrared light source used is 4.3 μm;

[0034] The specific contents of the reduction reaction products CH4 and CO were determined to be 1.7 μmol and 3.5 μmol, respectively, using a GC9790Plus gas chromatograph. Based on these contents, the generation rates of CH4 and CO were found to be 170 μmol / g / h and 350 μmol / g / h, respectively.

[0035] Comparative Example

[0036] The difference from Example 1 is that in step (3), the reactor is directly irradiated with an Xe lamp for 2 hours.

[0037] The specific contents of the reduction reaction products CH4 and CO were determined to be 1.5 μmol and 2.8 μmol, respectively, using a GC9790Plus gas chromatograph. Based on these contents, the generation rates of CH4 and CO were found to be 150 μmol / g / h and 280 μmol / g / h, respectively.

[0038] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for infrared photocatalytic reduction of carbon dioxide, characterized in that... The steps of this method include: The first step is to evenly coat the photocatalyst on the inner surface of the transparent reactor, then add deionized water into the transparent reactor, and finally use CO2 gas to purge the air in the transparent reactor. The second step involves simultaneously irradiating a transparent reactor with an Xe lamp that filters out infrared light and infrared light with wavelengths of 1.8 μm, 2.0 μm, 2.7 μm, 3.4 μm, or 4.3 μm to carry out a carbon dioxide reduction reaction. The photocatalyst is ZnO / Au / Cu. x O nanoparticles, x=1-2; In the second step, the power of the Xe lamp is 100-400 W; In the second step, the infrared light with wavelengths of 1.8 μm, 2.0 μm, 2.7 μm, 3.4 μm or 4.3 μm is an LED infrared lamp with a power of 0.1-100W; In the second step, when using Xe lamps that filter out infrared light and LED infrared lamps to simultaneously irradiate the transparent reactor, the Xe lamps that filter out infrared light need to irradiate the photocatalyst; the angle between the beam of the Xe lamp and the beam of the LED infrared lamp is 0-90°. In the second step, the reaction temperature is 20-30°C and the reaction time is 0.5-6 h.

2. The method for infrared photocatalytic reduction of carbon dioxide according to claim 1, characterized in that: In the first step, the transparent reactor is a quartz reactor or a glass reactor, and the pressure of the transparent reactor is 0.08-0.10 MPa.

3. The method for infrared photocatalytic reduction of carbon dioxide according to claim 1, characterized in that: In the second step, the method for filtering the infrared light in the Xe lamp is as follows: add an infrared filter at the exit of the Xe lamp light source or add a square transparent quartz container filled with water at the exit of the Xe lamp light source. The square transparent quartz container has a thickness of 3-6 cm in the light path direction.