Method for photocatalytic hydrogen generation by infrared light

Abstract

The application relates to a method for infrared photocatalytic hydrogen production, and belongs to the technical field of photocatalytic hydrogen production. A photocatalyst, methanol and water are added into a transparent reactor, and argon is used for purging to remove air in the transparent reactor; the transparent reactor is simultaneously irradiated by an Xe lamp filtering off infrared light and infrared light with wavelengths of 1.8 microns, 3.4 microns or 4.3 microns to carry out a hydrogen production reaction, the reaction temperature is 20-30 DEG C, and the reaction time is 0.5-6.0 hours; in the method, the infrared light with the wavelengths of 1.8 microns, 3.4 microns or 4.3 microns is applied to photocatalytic water decomposition and photocatalytic methanol reforming to produce hydrogen, so that the hydrogen production is improved.

Description

Technical Field

[0001] This invention relates to a method for producing hydrogen via infrared photocatalysis, belonging to the field of photocatalytic hydrogen production technology. Background Technology

[0002] Currently, approximately 81% of the energy used by humans comes from fossil fuels. The continuous development and utilization of traditional fossil fuels during industrial development has further exacerbated the energy crisis. Simultaneously, the utilization of fossil fuels releases large amounts of harmful pollutants, causing environmental pollution. Hydrogen energy, as a clean and renewable energy source, has a calorific value of 140 MJ / kg, far exceeding that of fossil fuels such as gasoline and diesel, making it an ideal alternative to traditional fossil fuels. The development and utilization of hydrogen energy has enormous potential. Currently, the main methods of hydrogen production include natural gas reforming, water electrolysis, coal gasification, and methane cracking. Among these, natural gas reforming and coal gasification still use fossil fuels as raw materials, while water electrolysis and methane cracking require a large amount of external energy input. In contrast, hydrogen production methods, including photocatalytic water splitting and photocatalytic methanol reforming, directly convert solar energy into hydrogen energy, making them cleaner and lower-cost hydrogen production methods. On the other hand, traditional photocatalytic hydrogen production reactions rely on the light absorption performance of photocatalytic materials, with the light utilization range mainly in the ultraviolet-visible region, resulting in relatively low hydrogen yield and quantum efficiency. Therefore, developing a clean, low-energy-consumption, and highly efficient hydrogen production method is of great significance. 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 to improve the yield of hydrogen production from photocatalytic water splitting and photocatalytic methanol reforming.

[0004] The technical solution of this invention is:

[0005] A method for producing hydrogen via infrared photocatalysis, the steps of which include:

[0006] The first step is to add the photocatalyst, methanol, and water into a transparent reactor, and then purge the reactor with argon gas to remove the air.

[0007] The second step involves simultaneously irradiating a transparent reactor with an Xe lamp that filters out infrared light and infrared light of a set wavelength to carry out a hydrogen production reaction. The reaction temperature is 20-30℃ and the reaction time is 0.5-6h.

[0008] When the molar ratio of methanol to water in the first step is less than or equal to 1, the wavelength set in the second step is 1.8 μm, 3.4 μm, or 4.3 μm.

[0009] When the molar ratio of methanol to water in the first step is greater than 1, the wavelength set in the second step is 1.8 μm, 3.4 μm, or 4.3 μm.

[0010] 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 TiO2 composite material, wherein the TiO2 composite material is Pt / TiO2, and the mass of Pt is 0.1%-3.0% of the mass of TiO2;

[0011] 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;

[0012] 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.

[0013] In the second step, the power of the Xe lamp is 100-400W;

[0014] In the second step, the infrared light of the set wavelength is an LED infrared lamp with a power of 0.1-100W;

[0015] In the second step, Xe lamps that filter out infrared light and LED infrared lamps are used to simultaneously irradiate the reaction liquid containing the photocatalyst in the transparent reactor. The angle between the beam of the Xe lamp and the beam of the LED infrared lamp is 0-90°.

[0016] In the first step, the mass ratio of the photocatalyst to the volume of methanol and water is 0.1-10 g: 1 L.

[0017] Through the above technical solution, the present invention achieves the following beneficial effects:

[0018] In the method of the present invention, infrared light of a set wavelength is applied to the photocatalytic water splitting and photocatalytic methanol reforming hydrogen production reactions, thereby increasing hydrogen production. Detailed Implementation

[0019] The present invention will be described in detail below through embodiments.

[0020] Example 1

[0021] A method for producing hydrogen via infrared photocatalysis, the steps of which include:

[0022] (1) Add 10 mg of 1% Pt / TiO2 (wt%) photocatalyst, 8 ml of water, and 2 ml of anhydrous methanol 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. Then place an LED infrared lamp on the side of the transparent reactor.

[0023] (2) An LED infrared light source with a power of 0.4W and an infrared wavelength of 1.8μm 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 illumination was carried out for 4 hours to complete the photocatalytic water splitting to produce hydrogen. The H2 yield was then sampled and tested.

[0024] The specific content of the reaction product H2 was determined to be 2.37 μmol using a GC9790Ⅱ gas chromatograph, and the generation rate of H2 was obtained as 59.25 μmol / g / h based on the specific content.

[0025] Example 2

[0026] (1) Add 10 mg of 1% Pt / TiO2 (wt%) photocatalyst, 2 ml of water, and 8 ml of anhydrous methanol to each 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. Then place an LED infrared lamp on the side of the transparent reactor.

[0027] (2) An LED infrared light source with a power of 0.4W and an infrared wavelength of 4.3μm 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 illumination was carried out for 4 hours to complete the photocatalytic methanol reforming to hydrogen production reaction and to sample and test the H2 yield.

[0028] The specific content of the reaction product H2 was determined to be 4.65 μmol using a GC9790Ⅱ gas chromatograph, and the generation rate of H2 was found to be 116.25 μmol / g / h based on the specific content.

[0029] Example 3

[0030] The difference from Example 1 is that the wavelength of the LED infrared light source used in step (2) is 3.4 μm.

[0031] The specific content of the reaction product H2 was determined to be 3.61 μmol using a GC9790Ⅱ gas chromatograph, and the generation rate of H2 was obtained as 90.25 μmol / g / h based on the specific content.

[0032] Example 4

[0033] The difference from Example 1 is that the wavelength of the LED infrared light source used in step (2) is 4.3 μm.

[0034] The specific content of the reaction product H2 was determined to be 2.85 μmol using a GC9790Ⅱ gas chromatograph, and the generation rate of H2 was obtained as 71.25 μmol / g / h based on the specific content.

[0035] Example 5

[0036] The difference from Example 2 is that the wavelength of the LED infrared light source used in step (2) is 1.8 μm.

[0037] The specific content of the reaction product H2 was determined to be 4.57 μmol using a GC9790Ⅱ gas chromatograph, and the generation rate of H2 was obtained as 106.75 μmol / g / h based on the specific content.

[0038] Example 6

[0039] The difference from Example 2 is that the wavelength of the LED infrared light source used in step (2) is 3.4 μm.

[0040] The specific content of the reaction product H2 was determined to be 6.32 μmol using a GC9790Ⅱ gas chromatograph, and the generation rate of H2 was obtained as 158.00 μmol / g / h based on the specific content.

[0041] Comparative Example 1

[0042] The difference from Example 1 is that in step (2), the reactor is directly irradiated with an Xe lamp for 4 hours.

[0043] The specific content of the reduction reaction product H2 was determined to be 0.95 μmol using a GC9790Ⅱ gas chromatograph, and the generation rate of H2 was found to be 23.75 μmol / g / h based on the specific content.

[0044] Comparative Example 2

[0045] The difference from Example 2 is that in step (2), the reactor is directly irradiated with an Xe lamp for 4 hours.

[0046] The specific content of the reduction reaction product H2 was determined to be 3.43 μmol using a GC9790Ⅱ gas chromatograph, and the H2 generation rate was found to be 85.75 μmol / g / h based on the specific content.

[0047] 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 producing hydrogen via infrared photocatalysis, characterized in that... The steps of this method include: The first step is to add the photocatalyst, methanol, and water into a transparent reactor, and then purge the reactor with argon gas to remove the air. The second step involves simultaneously irradiating a transparent reactor with an Xe lamp that filters out infrared light and infrared light of a set wavelength to carry out a hydrogen production reaction. When the molar ratio of methanol to water in the first step is less than or equal to 1, the wavelength set in the second step is 1.8 μm, 3.4 μm, or 4.3 μm. When the molar ratio of methanol to water in the first step is greater than 1, the wavelength set in the second step is 1.8 μm, 3.4 μm, or 4.3 μm. In the first step, the photocatalyst is Pt / TiO2, wherein the mass of Pt is 0.1%-3.0% of the mass of TiO2; In the first step, the mass ratio of the photocatalyst to the volume of methanol and water is 0.1-10 g: 1 L; 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. In the second step, the infrared light of the set wavelength is an LED infrared lamp with a power of 0.1-100W. The Xe lamp (which filters out infrared light) and the LED infrared lamp are used to simultaneously irradiate the reaction liquid containing the photocatalyst in the transparent reactor. The angle between the beam of the Xe lamp and the beam of the LED infrared lamp is 0-90°, the reaction temperature is 20-30°C, and the reaction time is 0.5-6.0 h.

2. The method for infrared photocatalytic hydrogen production 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 hydrogen production according to claim 1, characterized in that: In the second step, the power of the Xe lamp is 100-400 W.