Method for photo-initiated hydrogen production in the dark

Abstract

The present application relates to a kind of light initiation dark place hydrogen production method, belong to photochemical reaction hydrogen production technical field.Light catalyst, carbon-containing biomass derivative, alkali and water are added into transparent reactor;Light source of using light catalyst corresponding absorption wave band is used to irradiate reactor, and light excitation is carried out in room temperature air environment, and excitation time is several minutes to several hours, and then the reaction system is placed in dark condition, and hydrogen can be continuously precipitated from solution.The method of the present application applies biomass derivative to dark hydrogen precipitation reaction, so that the photocatalytic hydrogen precipitation reaction can continue in the dark, decouples light excitation and dark hydrogen precipitation reaction, and realizes the direct conversion of light energy to hydrogen energy in dark condition.

Description

Technical Field

[0001] This invention relates to a method for photo-initiated hydrogen production in the dark, belonging to the field of photocatalytic hydrogen production technology. Background Technology

[0002] Industrial development has exacerbated dependence on fossil fuels, and the environmental problems caused by over-exploitation have further led to the energy crisis. Hydrogen energy, with its high calorific value and zero carbon emissions, has become a highly competitive alternative energy source. However, the clean production, storage, and safe transportation of hydrogen still face significant challenges. Photocatalytic water splitting or methanol reforming, as a method of directly converting solar energy into hydrogen, is cleaner and lower cost-effective. However, current photocatalytic hydrogen production technologies heavily rely on continuous, high-intensity light energy input to drive the reaction, and are limited by the alternation of day and night and fluctuations in light intensity, resulting in a core bottleneck of activity interruption in dark environments. Traditional photocatalysis cannot maintain effective electron-hole pair separation under light-free conditions, leading to interruptions in hydrogen production and severely restricting continuous production and the coupling of renewable energy applications. Although attempts have been made to extend activity through energy storage media or noble metal co-catalysts, problems remain, such as excessively low hydrogen evolution reaction rates in the dark (e.g., the dark hydrogen production rate of Pt-based systems is less than 1% of that under light), short hydrogen evolution duration, and inability to repeat the process. Therefore, developing a hydrogen production method that uses light energy as input and can operate continuously and repeatedly even in dark conditions is of great significance. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the problem that existing photocatalytic technologies cannot continuously produce hydrogen under dark conditions, and to propose a photo-initiated method that can continuously and stably produce hydrogen from carbon-containing biomass derivatives and their aqueous solutions under dark conditions.

[0004] The technical solution of this invention is:

[0005] A method for photo-induced hydrogen production in the dark, the method comprising the following steps:

[0006] The first step is to mix the photocatalyst, alkali, and carbon-containing biomass derivative to obtain a mixture. If the mixture is entirely in a liquid or turbid state, proceed directly to the second step. If the mixture is neither entirely in a liquid nor in a turbid state, add water to make the mixture entirely in a liquid or turbid state to obtain the reactants.

[0007] The second step involves adding the reactants obtained in the first step into a transparent reactor, and then using a light source as the excitation source for hydrogen evolution in the dark in room temperature air to irradiate the transparent reactor.

[0008] The third step involves sealing the transparent reactor, which has been exposed to light, in a dark environment to carry out the hydrogen evolution reaction and collect the hydrogen gas.

[0009] In the first step, the alkali is sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, or ammonia.

[0010] In the first step, the types of carbon-containing biomass derivatives are cellulose, starch, glucose, methanol, ethanol, or fructose.

[0011] The photocatalyst is TiO2, ZnO, CdS, g-C3N4, graphene material, metal-organic framework material, TiO2 composite material, ZnO composite material, CdS composite material, g-C3N4 composite material, graphene composite material or metal-organic framework composite material;

[0012] In the second step, the light source is natural light, Xe lamp, or LED lamp with a corresponding absorption band of photocatalyst;

[0013] In the second step, the atmosphere inside the transparent reactor is air, and the temperature under light is room temperature;

[0014] In the second step, the illumination time shall not be less than 1 minute;

[0015] In the second 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;

[0016] In the third step, the hydrogen evolution reaction temperature is room temperature.

[0017] Beneficial effects

[0018] This invention relates to a photo-initiated method for hydrogen production in the dark, belonging to the field of photochemical reaction hydrogen production technology. A photocatalyst, a carbon-containing biomass derivative, an alkali, and water are added to a transparent reactor. The reactor is irradiated with a light source corresponding to the absorption band of the photocatalyst, and photoexcitation is performed in room temperature air for several minutes to several hours. The reaction system is then placed in darkness, allowing for continuous hydrogen evolution from the solution. In this method, the biomass derivative is applied to the dark hydrogen evolution reaction, enabling the photocatalytic hydrogen evolution reaction to continue in the dark, decoupling the photoexcitation and dark hydrogen evolution reactions, and achieving direct conversion of light energy into hydrogen energy under dark conditions. Detailed Implementation

[0019] The present invention will be further described below with reference to the embodiments.

[0020] A method for photo-induced hydrogen production in the dark, the method comprising the following steps:

[0021] The first step is to mix the alkali and carbon-containing biomass derivative in water, shake and sonicate to dissolve them, and obtain an alkaline turbid liquid or solution of the carbon-containing biomass derivative.

[0022] The second step involves adding the photocatalyst and an alkaline turbid liquid or solution of carbon-containing biomass derivatives into a transparent reactor, and then using a light source as an excitation source for hydrogen evolution in the dark under room temperature air to irradiate the transparent reactor.

[0023] The third step is to seal the system after it has been exposed to light and place it in a dark environment to carry out the hydrogen evolution reaction.

[0024] In the first step, an alkaline turbid liquid or solution containing carbon biomass derivatives is prepared, and the type of alkali is sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, or ammonia.

[0025] In the first step, the types of carbon-containing biomass derivatives are cellulose, starch, glucose, methanol, ethanol, and fructose.

[0026] In the first step, the volume ratio of liquid carbon-containing biomass derivatives to water is 0-100%, and the mass ratio of solid carbon-containing biomass derivatives to water is 0-100%.

[0027] In the first step, the concentration of the alkali in the liquid phase ranges from zero to saturation concentration (at room temperature).

[0028] In the second step, the photocatalyst is TiO2, ZnO, CdS, g-C3N4, graphene material, metal-organic framework material, TiO2 composite material, ZnO composite material, CdS composite material, g-C3N4 composite material, graphene composite material, or metal-organic framework composite material.

[0029] In the second step, the reaction light source includes natural light, Xe lamps, or LEDs with absorption bands corresponding to the photocatalyst.

[0030] In the second step, the reaction atmosphere is air and the reaction temperature is room temperature.

[0031] In the second step, the illumination time ranges from several minutes to several hours.

[0032] In the second 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.

[0033] In the third step, the hydrogen production temperature is room temperature and the hydrogen production environment is dark.

[0034] The present invention will be described in detail below through embodiments.

[0035] Example 1

[0036] A method for photo-induced hydrogen production in the dark, the method comprising the following steps:

[0037] (1) Add 2.5g of sodium hydroxide to 5ml of water. After the sodium hydroxide is completely dissolved, add 100mg of cellulose, sonicate and vibrate for about 20min to obtain a mixture;

[0038] (2) Add 0.5 mg of Pt / CdS nanorod photocatalytic material and 5 ml of the mixture obtained in step (1) to a transparent reaction flask, sonicate for 5 minutes and stir evenly, and seal the reaction flask;

[0039] (3) Subsequently, a PLS-SXE300E xenon lamp was used as the light source, with an illumination area of ​​15.90 cm². 2 The average light intensity is 300 mW / cm². 2 The reactor was continuously irradiated for 10 minutes. The specific content of the photocatalytic reaction product H2 was then determined using a GC9790Ⅱ gas chromatograph to be 1.55 μmol, and the hydrogen evolution amount was 3107.50 μmol / g.

[0040] (4) The system that has been excited by light was placed in a dark room, and the amount of hydrogen evolution in the system in the dark room was continuously monitored by GC9790Ⅱ gas chromatograph. After 1 hour, the total molar amount of hydrogen evolution in the dark was 1.17 μmol, the amount of hydrogen evolution was 2335.27 μmol / g, and the hydrogen evolution rate was 2335.27 μmol / g / h.

[0041] Example 2

[0042] A method for photo-induced hydrogen production in the dark, the method comprising the following steps:

[0043] (1) Add 2g of sodium hydroxide to 10ml of methanol, sonicate and shake for about 20min. After the sodium hydroxide is completely dissolved, centrifuge the solution at 8000rpm for about 8min to remove insoluble impurities and obtain a clear and transparent sodium hydroxide methanol solution.

[0044] (2) Add 100 mg of 1% Pt / TiO2 (wt%) photocatalyst and 50 ml of sodium hydroxide methanol solution to a transparent reaction flask. Sonicate for 5 minutes and stir well, then seal the reaction flask.

[0045] (3) Subsequently, a 365nm LED light was placed on the side of the transparent reactor as a light source, with an illumination area of ​​1cm². 2 The light intensity is 68mW / cm² 2 The reactor was continuously irradiated for 5 minutes. The specific content of the photocatalytic reaction product H2 was then determined using a GC9790Ⅱ gas chromatograph to be 0.68 μmol, and the hydrogen evolution amount was 6.77 μmol / g.

[0046] (4) The system that has been excited by light was placed in a dark room, and the amount of hydrogen evolution in the system in the dark room was continuously monitored by GC9790Ⅱ gas chromatograph. After 21 days, the total molar amount of hydrogen was 589.56 μmol, the amount of hydrogen evolution was 5895.60 μmol / g, and the average hydrogen evolution rate was 285.03 μmol / g / d.

[0047] Example 3

[0048] A method for photo-induced hydrogen production in the dark, the method comprising the following steps:

[0049] (1) Add 2g of sodium hydroxide to a mixed solution containing 5ml of methanol and 5ml of water, sonicate and shake for about 20min. After the alkali is completely dissolved, centrifuge the solution at 8000rpm for about 8min to remove insoluble impurities and obtain a clear and transparent alkaline methanol aqueous solution.

[0050] (2) Add 1 mg of Pt / CdS nanorod photocatalytic material and 10 ml of alkaline methanol aqueous solution to a transparent reaction flask, sonicate for 5 minutes and stir evenly, and seal the reaction flask.

[0051] (3) The transparent reactor was then placed outdoors for natural light exposure, with a light-receiving area of ​​approximately 45 cm². 2 The light intensity is approximately 70-100 mW / cm². 2 The illumination period was from 10:00 AM to 5:00 PM. The specific content of the photocatalytic reaction product H2 was determined to be 1166.78 μmol using a GC9790Ⅱ gas chromatograph, and the hydrogen evolution amount was 1166.78 mmol / g.

[0052] (4) The light-excited system was placed in a dark room, and the amount of hydrogen evolution in the system was continuously monitored in the dark room using a GC9790Ⅱ gas chromatograph. After 17 hours, the total molar amount of hydrogen evolution in the dark was 154.62 μmol, the amount of hydrogen evolution was 154.62 mmol / g, and the average hydrogen evolution rate was 9.10 mmol / g / h.

[0053] Example 4

[0054] A method for photo-induced hydrogen production in the dark, the method comprising the following steps:

[0055] (1) Add 5g of sodium hydroxide to 10ml of water. After the alkali is completely dissolved, add 6g of glucose, sonicate and shake for about 20 minutes.

[0056] (2) Add a mixture of 1 mg Pt / CdS nanorod photocatalyst material and 10 ml glucose alkaline aqueous solution to a transparent reaction flask. Sonicate for 5 minutes and stir well, then seal the reaction flask.

[0057] (3) Subsequently, a PLS-SXE300E xenon lamp was used as the light source, with an illumination area of ​​15.90 cm². 2 The average light intensity is 300 mW / cm². 2 The reactor was continuously irradiated for 10 minutes. The specific content of the photocatalytic reaction product H2 was then determined using a GC9790Ⅱ gas chromatograph to be 14.99 μmol, and the hydrogen evolution amount was 14993.07 μmol / g.

[0058] (4) The system that has been excited by light was placed in a dark room, and the amount of hydrogen evolution in the system in the dark room was continuously monitored by GC9790Ⅱ gas chromatograph. After 1 hour, the total molar amount of hydrogen evolution in the dark was 5.68 μmol, the amount of hydrogen evolution was 5677.38 μmol / g, and the hydrogen evolution rate was 5677.38 μmol / g / h.

[0059] Example 5

[0060] A method for photo-induced hydrogen production in the dark, the method comprising the following steps:

[0061] (1) Add 18.75 mg of calcium oxide to a mixed solution containing 5 ml of methanol and 5 ml of water, sonicate and shake for about 20 min. After the alkali is completely dissolved, centrifuge the solution at 8000 rpm for about 8 min to remove insoluble impurities and obtain a clear and transparent calcium hydroxide methanol solution.

[0062] (2) Add 1 mg of Pt / CdS nanorod photocatalyst material and 10 ml of calcium hydroxide methanol solution to a transparent reaction flask. Sonicate for 5 minutes and stir well, then seal the reaction flask.

[0063] (3) Subsequently, a PLS-SXE300E xenon lamp was used as the light source, with an illumination area of ​​15.90 cm². 2 The average light intensity is 300 mW / cm². 2 The reactor was continuously irradiated for 30 minutes. The specific content of the photocatalytic reaction product H2 was then determined using a GC9790Ⅱ gas chromatograph to be 21.12 μmol, and the hydrogen evolution amount was 21.12 mmol / g.

[0064] (4) The system that has been excited by light was placed in a dark room, and the amount of hydrogen evolution in the system in the dark room was continuously monitored by GC9790Ⅱ gas chromatograph. After 5 days, the total molar amount of hydrogen evolution in the dark was 5.23 μmol, the amount of hydrogen evolution was 5.23 mmol / g, and the average hydrogen evolution rate was 1.04 mmol / g / d.

[0065] 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 photo-initiated hydrogen production in the dark, characterized in that... The steps of this method include: The first step is to mix the photocatalyst, alkali, and carbon-containing biomass derivatives to obtain the reactants; The second step involves adding the reactants obtained in the first step into a transparent reactor, and then using a light source as the excitation source for hydrogen evolution in the dark in room temperature air to irradiate the transparent reactor. The third step is to seal the transparent reactor after it has been exposed to light and place it in a dark environment to carry out the hydrogen evolution reaction and collect the hydrogen gas. In the second step, the atmosphere inside the transparent reactor is air, the light temperature is room temperature, and the light exposure time is not less than 1 minute. In the second 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; In the third step, the hydrogen evolution reaction temperature is room temperature; In the first step, when the photocatalyst, alkali, and carbon-containing biomass derivatives are all solids, water is added to obtain the reactants. In the first step, when the photocatalyst, alkali, and carbon-containing biomass derivatives are not all solids, water is also added to obtain the reactants. In the first step, the types of carbon-containing biomass derivatives are cellulose, starch, glucose, methanol, ethanol, or fructose. In the first step, the photocatalyst is TiO2, ZnO, CdS, g-C3N4, WO3 graphene material, metal-organic framework material, TiO2 composite material, ZnO composite material, CdS composite material, g-C3N4 composite material, graphene composite material, or metal-organic framework composite material.

2. The method for photo-initiated hydrogen production in the dark according to claim 1, characterized in that: In the first step, the alkali is sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, or ammonia.

3. The method for photo-initiated hydrogen production in the dark according to claim 1, characterized in that: In the second step, the light source is natural light, Xe lamp, or LED lamp with a corresponding absorption band of photocatalyst.