A method for photocatalytic steam reforming of methanol to hydrogen based on optical wavelength regulation

Abstract

The present invention belongs to the technical field of photothermal catalysis, and more specifically relates to a method for photocatalytic steam reforming of methanol to hydrogen based on light wavelength regulation. In the present invention, during the thermal catalysis process of steam reforming of methanol to hydrogen, a single-wavelength light with a wavelength range of 200-1000 nm is introduced to irradiate the catalyst according to the change of reaction temperature, so that the reaction system driven by waste heat can exhibit the optimal performance of the catalyst at different temperatures and improve the hydrogen production performance. By constructing a wavelength-responsive catalyst and using light in a specific wavelength band to regulate the reaction energy barrier, the present invention realizes the dynamic matching of the activation energy of the methanol reforming reaction within a wide temperature range, breaks through the bottleneck of the low coupling efficiency of temperature and light intensity in traditional technologies, and provides an innovative solution for the gradient utilization of industrial waste heat.

Description

Technical Field

[0001] The present invention belongs to the technical field of photothermal catalysis, and more specifically relates to a method for photocatalytic steam reforming of methanol to hydrogen based on light wavelength regulation. Background Art

[0002] As an important way for clean energy conversion, steam reforming of methanol to hydrogen has broad application prospects in fields such as fuel cells and chemical synthesis. Traditional thermal catalysis technology mainly relies on a high-temperature (250 - 350 °C) environment to drive the reaction, and there are problems such as high energy consumption and easy sintering and deactivation of the catalyst. In recent years, the introduction of photocatalysis technology has provided a new idea for reducing the reaction temperature. By promoting surface reactions with photo-generated carriers, the activation energy can be partially reduced. However, a single photocatalytic system is limited by problems such as a narrow light absorption range, a high carrier recombination rate, and an unclear photo-thermal synergy mechanism, and it is difficult to achieve efficient and stable catalytic performance in a wide temperature range.

[0003] The waste heat temperature range in industrial production processes is wide (100 °C to 900 °C), and the specific temperature depends on industry and process requirements. Utilizing waste heat to drive chemical reactions to produce high-value chemicals can reduce energy consumption and production costs. Traditional thermal catalytic materials have a fixed activation energy, but when the reaction temperature changes due to fluctuations in waste heat, they cannot adaptively adjust the reaction path, resulting in insufficient activity in the low-temperature section and increased side reactions in the high-temperature section. Existing research mostly focuses on optimizing the performance under single light / heat conditions and does not solve the problem of poor temperature adaptability, and cannot ensure optimal catalytic performance at different temperatures.

[0004] In view of this, developing a catalytic system that can dynamically adjust the activation energy according to the waste heat temperature and achieve photo-thermal synergistic enhancement has become a technical difficulty. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for photocatalytic steam reforming of methanol to hydrogen based on light wavelength regulation to solve the problems existing in the above-mentioned prior art, maintain the best catalytic performance when the reaction temperature changes due to waste heat fluctuations, and achieve a higher hydrogen production under the same reaction conditions.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention: provides a method for maintaining the best hydrogen production performance in the steam reforming of methanol to hydrogen under temperature fluctuation conditions, and introducing light of a single wavelength to irradiate the catalyst according to the fluctuation of the reaction temperature during the thermal catalysis of the steam reforming of methanol to hydrogen;

[0008] The wavelength of the light of the single wavelength is 200 - 1000 nm;

[0009] The reaction temperature is 150 - 250 °C.

[0010] Further, introducing light of a single wavelength to irradiate the catalyst according to the fluctuation of the reaction temperature specifically includes: when the reaction temperature is 150 - 190 °C, the wavelength of the introduced light source is 200 - 600 nm; when the reaction temperature is greater than 190 °C (i.e., the reaction temperature is 190 (excluding) - 250 °C), the wavelength of the introduced light source is 200 - 1000 nm.

[0011] Optionally, when the reaction temperature is 150 - 190 °C, the wavelength of the introduced light source is 200 - 500 nm; when the reaction temperature is greater than 190 °C (i.e., the reaction temperature is 190 (excluding) - 250 °C), the wavelength of the introduced light source is greater than 500 nm (i.e., light of a single wavelength with a wavelength of 500 (excluding) - 1000 nm).

[0012] At low temperatures, light with a low wave number can stimulate the activity of the catalyst to a greater extent. When the reaction is at a higher temperature, light with a slightly larger wave number is required. However, as long as there is light irradiation at a higher temperature, the activity of the catalyst can be well stimulated. Therefore, when the temperature is low, light with a lower wavelength is introduced to enhance the low-temperature catalytic activity of the catalyst. At a higher reaction temperature, the wavelength limit of the light is not particularly obvious, and only light of a single wavelength needs to be maintained.

[0013] The second technical solution of the present invention: provides a method for photo-thermal catalytic steam reforming of methanol to produce hydrogen based on light wavelength regulation, including:

[0014] During the thermal catalytic process of steam reforming of methanol to produce hydrogen, light of a single wavelength in the range of 200 - 1000 nm is introduced to irradiate the catalyst according to the change of the reaction temperature;

[0015] The heat energy in the thermal catalytic process is provided by the waste heat of the steam reforming reaction of methanol to produce hydrogen;

[0016] The temperature change range provided by the waste heat is 150 - 250 °C.

[0017] Based on the unstable temperature during the steam reforming reaction of methanol to produce hydrogen driven by waste heat as a heat source, different wavelengths of light are introduced according to the temperature change, so that the optimal performance of the catalyst can be exerted at different temperatures, and the hydrogen production performance is improved.

[0018] Further, the steps of the photo-thermal catalytic steam reforming of methanol to produce hydrogen based on light wavelength regulation include:

[0019] Using an aqueous methanol solution as the reaction substrate, placing the catalyst above the reaction substrate, heating to the reaction temperature under an inert atmosphere, introducing a light source with a single wavelength to irradiate the catalyst, performing the methanol steam reforming reaction for hydrogen production, and cooling to room temperature to collect the gas product and waste heat; the heating is to drive the methanol steam reforming reaction for hydrogen production using the collected waste heat; adjusting the wavelength of the introduced light source according to the different reaction temperatures provided by the waste heat.

[0020] Optionally, the power density of the light source is 0 - 3 W / cm 2 , and it is not 0.

[0021] Optionally, when the reaction temperature is 150 - 190 °C, the wavelength of the introduced light source is 200 - 600 nm.

[0022] Optionally, when the reaction temperature is greater than 190 °C (i.e., the reaction temperature is 190 (excluding) - 250 °C), the wavelength of the introduced light source is 200 - 2000 nm.

[0023] Preferably, when the reaction temperature is 150 - 190 °C, the wavelength of the introduced light source is 200 - 500 nm; when the reaction temperature is greater than 190 °C (i.e., the reaction temperature is 190 (excluding) - 250 °C), the wavelength of the introduced light source is greater than 500 nm (i.e., light with a single wavelength of 500 (excluding) - 1000 nm).

[0024] Optionally, the molar ratio of methanol to water in the aqueous methanol solution is 1:1.

[0025] Optionally, the catalyst is a copper-based catalyst.

[0026] Preferably, the copper-based catalyst includes Cu / TiO2 or Cu / ZnO / Al2O3.

[0027] Optionally, the inert atmosphere is provided by at least one of N2, He, Ne, Ar, Kr, and Xe.

[0028] The third technical solution of the present invention: providing a method for maintaining the best hydrogen production performance of the methanol steam reforming reaction under the above temperature fluctuation conditions or the application of the above method of photo-thermal catalytic methanol steam reforming for hydrogen production based on light wavelength regulation in photo-thermal catalytic methanol steam reforming for hydrogen production.

[0029] The fourth technical solution of the present invention: providing a method for improving the activity stability of the catalyst for methanol steam reforming for hydrogen production driven by waste heat, the method being to apply light with a single wavelength to the catalyst based on the change in the reaction temperature driven by waste heat during the methanol steam reforming reaction for hydrogen production;

[0030] The wavelength of the single-wavelength light is 200 - 1000 nm.

[0031] Furthermore, when the reaction temperature is 150 - 190 °C, the wavelength of the applied light is 200 - 600 nm.

[0032] Furthermore, when the reaction temperature is greater than 190 °C (i.e., the reaction temperature is 190 (excluding) - 250 °C), the wavelength of the applied light is 200 - 1000 nm.

[0033] Optionally, when the reaction temperature is 150 - 190 °C, the wavelength of the introduced light source is 200 - 500 nm; when the reaction temperature is greater than 190 °C (i.e., the reaction temperature is 190 (excluding) - 250 °C), the wavelength of the introduced light source is greater than 500 nm (i.e., single-wavelength light with a wavelength of 500 (excluding) - 1000 nm).

[0034] The present invention discloses the following technical effects:

[0035] Based on thermal catalysis, the present invention introduces light sources of different single wavelengths. Different wavelengths drive changes in the reaction path and exhibit different activation energies, which can be used in chemical reactions driven by waste heat recovery with large temperature fluctuations, and can exert the optimal performance of the catalyst at different temperature stages of waste heat utilization, maximizing the benefits brought by waste heat recovery.

[0036] By constructing a wavelength-responsive catalyst, the present invention uses light in a specific band to regulate the reaction energy barrier, achieving dynamic matching of the activation energy of the methanol reforming reaction within a wide temperature range, breaking through the bottleneck of low temperature-light intensity coupling efficiency in traditional technologies, and providing an innovative solution for the gradient utilization of industrial waste heat. Description of the Drawings

[0037] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0038] Figure 1 Shows the hydrogen production performance of the Cu / TiO2 catalyst in Example 1 at different temperatures and light wavelengths;

[0039] Figure 2 Shows the hydrogen production activation energy of the Cu / TiO2 catalyst in Example 1 at different light wavelengths;

[0040] Figure 3 Shows the hydrogen production performance of the Cu / ZnO / Al2O3 catalyst in Example 2 at different temperatures and light wavelengths;

[0041] Figure 4The hydrogen production activation energy of the Cu / ZnO / Al2O3 catalyst in Example 2 at different light wavelengths;

[0042] Figure 5 The hydrogen production performance of the Cu / TiO2 catalyst in Comparative Example 1 without introducing light and with introducing light at 190 °C;

[0043] Figure 6 The hydrogen production performance of the Cu / TiO2 catalyst in Comparative Example 2 under full spectrum and at different wavelengths at different temperatures;

[0044] Figure 7 The hydrogen production performance of the Cu / TiO2 catalyst in Comparative Example 3 at different temperatures without introducing light. Detailed implementation manners

[0045] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0046] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0047] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0048] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are only exemplary.

[0049] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0050] It should be noted that the aspects not described in detail in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0051] In some specific embodiments, the present invention provides a method for photocatalytic steam reforming of methanol to hydrogen based on optical wavelength regulation, and the steps include:

[0052] S1. Add the catalyst and the solvent into a sealed container, disperse them evenly by ultrasonic treatment, drop the mixture onto a glass slide, and dry it using a heating stage until the solvent has completely evaporated, obtaining a glass slide loaded with the catalyst;

[0053] S2. Add an aqueous methanol solution into a reaction kettle with a light window as the reaction substrate, place the glass slide loaded with the catalyst in step S1 above the reaction substrate, and separate the reaction substrate from the glass slide loaded with the catalyst without contact;

[0054] S3. After the reaction kettle is sealed, displace the air in the reaction kettle with an inert gas, heat it to the reaction temperature, turn on the light source, and irradiate the glass slide loaded with the catalyst with light having a wavelength of 200 - 1000 nm and a power density of 0 - 3 W / cm 2 (not zero). The vaporized methanol steam contacts the catalyst through heating, and a steam reforming reaction occurs. After cooling to room temperature, the gas and the waste heat are collected, and the waste heat is used to drive the steam reforming reaction.

[0055] In some specific embodiments, in step S1:

[0056] The catalyst is a copper-based catalyst, preferably Cu / TiO2 or Cu / ZnO / Al2O3;

[0057] The solvent includes at least one of methanol, ethanol, and propanol;

[0058] The glass slide includes quartz glass, borosilicate glass, high-aluminum glass, or soda-lime glass;

[0059] The dosage ratio of the catalyst to the solvent is 5 - 300 mg: 1 - 5 mL.

[0060] In some specific embodiments, in step S2:

[0061] The molar ratio of methanol to water in the aqueous methanol solution is 1:1.

[0062] In some specific embodiments, in step S3:

[0063] The inert gas includes at least one of N2, He, Ne, Ar, Kr, and Xe;

[0064] The temperature heated to the reaction temperature is 150 - 350 °C;

[0065] The light source includes a xenon lamp or other replaceable light sources;

[0066] The wavelength of the light can be regulated by a filter.

[0067] In the specific implementation of the present invention, both normal temperature and room temperature refer to 20 - 30 °C.

[0068] The raw materials and reagents used in the present invention are all commercially available products. Among them, Cu / TiO2 or Cu / ZnO / Al2O3 can be commercially available products or self - made products, which does not affect the realization of the technical effect. An exemplary preparation method of Cu / TiO2 or Cu / ZnO / Al2O3 is given below:

[0069] The preparation steps of Cu / TiO2 include:

[0070] 0.475 g of copper nitrate trihydrate, 0.5 g of titanium dioxide, 1 g of ascorbic acid and 6 g of polyvinylpyrrolidone are dissolved in 40 mL of ultrapure water. 10 mL of an aqueous solution containing 0.9 g of sodium borohydride is added dropwise. After stirring for 10 h, it is centrifuged and vacuum - dried, calcined in air at 400 °C for 4 h, and reduced with 8% H2 / Ar at 350 °C for 1 h to obtain Cu / TiO2.

[0071] The preparation steps of Cu / ZnO / Al2O3 include:

[0072] 3.84 g of copper nitrate trihydrate, 3.16 g of zinc nitrate hexahydrate and 0.99 g of aluminum nitrate nonahydrate are dissolved in 100 mL of deionized water. 100 mL of an aqueous solution containing 3.5 g of sodium carbonate is added dropwise. After oil - bathing at 100 °C for 12 h, it is centrifuged, washed and dried, calcined in air at 380 °C for 3 h, and reduced with 8% H2 / Ar at 350 °C for 1 h to obtain Cu / ZnO / Al2O3.

[0073] Example 1

[0074] The steps of photocatalytic steam reforming of methanol to hydrogen using Cu / TiO2 as a catalyst include:

[0075] S1. Dissolve 50 mg of Cu / TiO2 catalyst in 1 mL of methanol solution, ultrasonicate for 10 min, and use a dropper to evenly drop it on a circular quartz glass sheet, and dry it at 70 °C on a heating table to obtain a quartz glass sheet loaded with the catalyst;

[0076] S2. Take 40 mL of methanol aqueous solution (the molar ratio of methanol to water is 1:1), pour it into a high - pressure reactor with a light window, and put the quartz glass sheet loaded with the catalyst into the high - pressure reactor and place it above the methanol aqueous solution;

[0077] S3. After tightening the screws of the reactor for sealing, replace the air atmosphere inside the reactor with nitrogen, heat the reactor using the waste heat from methanol steam reforming for hydrogen production, and irradiate the quartz glass sheet loaded with the catalyst with a light intensity of 300 mw / cm 2 at 180, 190 or 200 °C using a xenon lamp. Among them, a filter is used to introduce light wavelengths of 405 nm, 578 nm or 650 nm. After reacting for 75 min, cool the reactor to room temperature to collect the gas and waste heat.

[0078] Detect the hydrogen content of the collected gas by gas chromatography, and the results are as Figure 1 shown.

[0079] Figure 1 This is the hydrogen production performance of the Cu / TiO2 catalyst in Example 1 at different temperatures and light wavelengths. As can be seen from the figure, the reactions are significantly different at different wavelengths. At lower temperatures (180 °C and 190 °C), the catalytic performance is the highest in the photo-thermal synergistic reaction with a wavelength of 405 nm, showing excellent low-temperature activity. At higher temperatures, the catalytic performance is the highest in the photo-thermal synergistic reaction with a wavelength of 578 nm, and the hydrogen production is close to 50 mmol g -1 h -1 .

[0080] Figure 2 This is the hydrogen production activation energy of the Cu / TiO2 catalyst in Example 1 at different light wavelengths. As can be seen from the figure, the activation energies at wavelengths of 405 nm, 578 nm, and 650 nm are 162.74 kJ mol -1 , 231.24 kJ mol -1 and 215.78 kJ mol -1 respectively.

[0081] Through Figure 1 - Figure 2 , it can be seen that the lower activation energy (162.74 kJ / mol) at 405 nm indicates that the photo-thermal reforming of methanol vapor for hydrogen production under this condition is light-dominated and can effectively promote the generation of hydrogen at lower temperatures, so the low-temperature activity is good; while the higher activation energy (231.24 kJ / mol) at 578 nm indicates that the reaction under this condition is more dependent on the thermal effect and is heat-dominated, and the best catalytic performance can be achieved at higher temperatures, so the high-temperature activity is good. Therefore, the waste heat recovery is used to drive the photo-thermal reforming of methanol vapor for hydrogen production. When the waste heat temperature is low, light with a wavelength of 405 nm can be introduced, and when the waste heat temperature is high, light with a wavelength of 578 nm can be introduced, so as to achieve the purpose of improving the benefit.

[0082] Example 2

[0083] The steps of photo-thermal catalytic methanol steam reforming for hydrogen production using Cu / ZnO / Al2O3 as the catalyst include:

[0084] S1. Dissolve 50 mg of Cu / ZnO / Al2O3 catalyst in 1 mL of methanol solution, sonicate for 10 min, and evenly drip it onto a circular quartz glass slide using a dropper. Dry it at 70 °C on a heating stage to obtain a quartz glass slide loaded with the catalyst;

[0085] S2. Take 40 mL of methanol aqueous solution (molar ratio of methanol to water is 1:1), pour it into a high-pressure reactor with a light window, and place the quartz glass slide loaded with the catalyst into the high-pressure reactor above the methanol aqueous solution;

[0086] S3. After tightening the screws of the reactor to seal it, displace the air atmosphere in the reactor with nitrogen, heat the reactor using the waste heat from methanol steam reforming to produce hydrogen, and irradiate the quartz glass slide loaded with the catalyst with a light intensity of 300 mw / cm 2 at 180, 190 or 200 °C using a xenon lamp. Introduce light wavelengths of 405 nm, 578 nm or 650 nm using a filter. After reacting for 75 min, cool the reactor to room temperature and collect the gas and waste heat.

[0087] Figure 3 This is the hydrogen production performance of the Cu / ZnO / Al2O3 catalyst in Example 2 at different temperatures and light wavelengths.

[0088] Figure 4 This is the hydrogen production activation energy of the Cu / ZnO / Al2O3 catalyst in Example 2 at different light wavelengths.

[0089] Through the Figure 3 and Figure 4 of Example 2 and the Figure 1 and Figure 2 of Example 1 for comparison, it is found that although the wavelengths and catalysts used are different from those in Example 1, the differences in different wavelengths are still shown, indicating the general performance of the method of the present invention. Furthermore, it can be extended to other catalysts and has a wide application range.

[0090] Comparative Example 1

[0091] Compared with Example 1, the difference is that the reaction temperature is 190 °C and no light source is introduced. The specific steps include:

[0092] S1. Dissolve 50 mg of Cu / TiO2 catalyst in 1 mL of methanol solution, sonicate for 10 min, and evenly drip it onto a circular quartz glass slide using a dropper. Dry it at 70 °C on a heating stage to obtain a quartz glass slide loaded with the catalyst;

[0093] S2. Take 40 mL of methanol aqueous solution (molar ratio of methanol to water is 1:1), pour it into a high-pressure reactor with a light window, and put the quartz glass sheet loaded with the catalyst into the high-pressure reactor, placing it above the methanol aqueous solution;

[0094] S3. After tightening the screws of the reactor to seal it, use nitrogen to displace the air atmosphere in the reactor, heat the reactor with the waste heat of methanol steam reforming for hydrogen production. After heating to 190 °C and reacting for 75 min, cool the reactor to room temperature and collect the gas.

[0095] Figure 5 It is the hydrogen production performance of the Cu / TiO2 catalyst in Comparative Example 1 without introducing light and with introducing light at 190 °C. As can be seen from the figure, at the same reaction temperature, when the light with a wavelength of 200 - 1000 nm is not applied for assistance, its reaction performance is significantly reduced.

[0096] Comparative Example 2

[0097] Compared with Example 1, the difference is that the reaction temperature is 190 °C and a filter is not used to introduce a specific wavelength light source. The specific steps include:

[0098] S1. Dissolve 50 mg of Cu / TiO2 catalyst in 1 mL of methanol solution, ultrasonicate for 10 min, and use a dropper to evenly drip it on a circular quartz glass sheet, and dry it at 70 °C on a heating table to obtain a quartz glass sheet loaded with the catalyst;

[0099] S2. Take 40 mL of methanol aqueous solution (molar ratio of methanol to water is 1:1), pour it into a high-pressure reactor with a light window, and put the quartz glass sheet loaded with the catalyst into the high-pressure reactor, placing it above the methanol aqueous solution;

[0100] S3. After tightening the screws of the reactor to seal it, use nitrogen to displace the air atmosphere in the reactor, heat the reactor with the waste heat of methanol steam reforming for hydrogen production, and irradiate the quartz glass sheet loaded with the catalyst with a light intensity of 300 mw / cm 2 using a xenon lamp at 180, 190 or 200 °C (without using a filter, that is, full-spectrum irradiation). After reacting for 75 min, cool the reactor to room temperature and collect the gas and waste heat.

[0101] Figure 6 It is the hydrogen production performance of the Cu / TiO2 catalyst in Comparative Example 2 under full-spectrum and different wavelengths at different temperatures. As can be seen from the figure, 300 mw / cm 2The hydrogen production performance under full-spectrum irradiation is inferior to that of light sources with wavelengths of 405 nm and 578 nm under the same light intensity. The hydrogen production performance of the 650-nm light source is lower than that of the full spectrum because this wavelength belongs to infrared light and has limited ability to excite the semiconductor. In summary, introducing single-wavelength light can maximize the activation of the catalyst activity.

[0102] Comparative Example 3

[0103] Compared with Example 1, the difference is that no light source is introduced, and the same catalytic effect is achieved. The specific steps include:

[0104] S1. Dissolve 50 mg of Cu / TiO2 catalyst in 1 mL of methanol solution, ultrasonicate for 10 min, and use a dropper to evenly drop it on a circular quartz glass sheet, and dry it at 70 °C on a heating table to obtain a quartz glass sheet loaded with the catalyst;

[0105] S2. Take 40 mL of methanol aqueous solution (molar ratio of methanol to water is 1:1), pour it into a high-pressure reactor with a light window, and put the quartz glass sheet loaded with the catalyst into the high-pressure reactor and place it above the methanol aqueous solution;

[0106] S3. After tightening the screws of the reactor to seal it, use nitrogen to displace the air atmosphere in the reactor, heat the reactor, after reacting for 75 min, cool the reactor to room temperature to collect the gas, detect the hydrogen content, and record the reaction temperature when the same hydrogen production performance as in Example 1 (200 °C, 578-nm wavelength light) is achieved.

[0107] When reducing the introduction of a specific wavelength, if the same hydrogen production performance as in Example 1 (200 °C, 578-nm wavelength light) is to be achieved, the required reaction temperature needs to be higher than 230 °C. It can be seen that introducing a specific wavelength of light in the present invention can also reduce the reaction temperature required.

[0108] Figure 7 It is the hydrogen production performance of the Cu / TiO2 catalyst in Comparative Example 3 without light irradiation at different temperatures.

[0109] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0110] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for maintaining the optimal hydrogen production performance of methanol steam reforming for hydrogen production under temperature fluctuation conditions, characterized in that, During the thermal catalytic process of hydrogen production by methanol steam reforming, a single-wavelength light is introduced to irradiate the catalyst according to the fluctuation of the reaction temperature; The specific steps of introducing a single-wavelength light to irradiate the catalyst according to the fluctuation of the reaction temperature include: When the reaction temperature is 150 - 190 °C, the wavelength of the introduced light source is a single-wavelength light with a wavelength of 200 - 500 nm; When the reaction temperature is greater than 190 °C, the wavelength of the introduced light source is a single-wavelength light with a wavelength of 500 nm - 1000 nm, excluding 500 nm.

2. A method for photocatalytic steam reforming of methanol to hydrogen based on optical wavelength regulation, characterized in that, It includes: Using an aqueous methanol solution as the reaction substrate, placing the catalyst above the reaction substrate, heating to the reaction temperature under an inert atmosphere, introducing a single-wavelength light source to irradiate the catalyst, conducting the methanol steam reforming reaction to produce hydrogen, cooling to room temperature to collect the gas product and waste heat; the collected waste heat is used to heat and drive the methanol steam reforming reaction; the wavelength of the introduced light source is dynamically adjusted according to the fluctuation of the reaction temperature; When the reaction temperature is 150 - 190 °C, the wavelength of the introduced light source is 200 - 500 nm; When the reaction temperature is greater than 190 °C, the wavelength of the introduced light source is 500 - 1000 nm, excluding 500 nm.

3. The method according to claim 2, wherein The power density of the light source is 0 - 1 W / cm 2 , and is not 0; and / or, the molar ratio of methanol to water in the methanol aqueous solution is 1:1; and / or, the catalyst is a copper-based catalyst; and / or, the inert atmosphere is provided by at least one of N2, He, Ne, Ar, Kr, and Xe.

4. Use of the method according to claim 1 or the method according to any one of claims 2 - 3 in the photo-thermal catalytic methanol steam reforming for hydrogen production.

5. A method for improving the activity stability of a catalyst for hydrogen production by methanol steam reforming driven by waste heat, characterized in that, The method applies a single-wavelength light to the catalyst based on the change in the reaction temperature driven by waste heat during the methanol steam reforming reaction process; When the reaction temperature is 150 - 190 °C, the wavelength of the introduced light source is 200 - 500 nm; When the reaction temperature is greater than 190 °C, the wavelength of the introduced light source is 500 - 1000 nm, excluding 500 nm.

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