KR20210012383A - Method for hydrogen production using iron oxyhydroxide - Google Patents

Abstract

The present invention relates to a method for producing hydrogen using iron oxyhydroxide. The method includes the steps of: (a) dipping a material including iron oxyhydroxide (FeOOH) in a mixed solution of water containing Fe^2+ and Fe^3+ with a lower alcohol; and (b) irradiating light to the material including iron oxyhydroxide and the mixed solution to produce gaseous hydrogen. According to the method for producing hydrogen using iron oxyhydroxide according to the present invention, it is possible to produce hydrogen through the decomposition of water and a lower alcohol by generating hydroxy radical (·OH) through the photo-Fenton reaction on the surface of the material including iron oxyhydroxide merely by carrying out light irradiation with no need for carrying out voltage application and light irradiation at the same time. In addition, since the iron oxyhydroxide supplied to the photo-Fenton reaction is regenerated through the reaction with a solution of Fe^2+ or oxygen in the air, it is possible to perform radical generation and hydrogen production semi-permanently. Further, since water treatment and energy production are allowed, with the proviso that iron oxyhydroxide contained in easily available corroded iron and an environment capable of irradiation are provided merely, the present invention shows significant advantages in terms of hydrogen production costs and process simplicity.

Description

Hydrogen production method using iron oxyhydroxide{METHOD FOR HYDROGEN PRODUCTION USING IRON OXYHYDROXIDE}

The present invention relates to a hydrogen production method, and more particularly, to a method for producing hydrogen using iron oxyhydroxide treated as a waste resource.

Korea is a poor country in energy resources and relies heavily on imports for its energy consumption, which is within the top 10 in the world, and the economy is greatly affected by world oil prices, so it is difficult to develop and use renewable energy that can be sustainably grown to secure energy security. Not only is it urgent, but as the world's 9th-largest greenhouse gas emitter, the pressure to reduce greenhouse gas emissions is increasing internationally.

Therefore, hydrogen energy is attracting great attention as a future clean energy capable of simultaneously solving environmental problems such as global warming and problems related to energy dependence.

Hydrogen energy is in the spotlight as an energy to replace fossil energy in the future as it does not emit substances that can adversely affect the environment, such as carbon dioxide, NOx, and SOx, while the calorific value per weight is three times higher than that of petroleum.

On the other hand, there are various methods of producing hydrogen, but currently, production by reforming hydrocarbons is more economical than the method of electrolyzing water, and production is excellent.

Accordingly, the hydrogen production method through the reforming pyrolysis process of hydrocarbons has already been put into practical use, but the production cost of hydrogen is still very high compared to fossil fuels, and the storage problem is accompanied. Also, this technology also generates products such as carbon dioxide. It is not so free to environmental problems that its use is very limited.

Therefore, there is a need to develop an economical and eco-friendly hydrogen production method compared to the above-described conventional technology.

Korean Patent Application Publication No. 10-2018-0022606 (published date: 2018.03.06) Japanese Patent Application Publication No. 2016-199439 (published date: 2016.12.01) Japanese Patent Application Publication No. 2013-053060 (published date: 2013.03.21)

The technical problem to be solved by the present invention is that hydrogen production is possible through a more economical and simpler method compared to the existing hydrogen production method, and in particular, it is considered as a waste resource without using expensive materials such as platinum (Pt). It is to provide a method that can economically produce hydrogen through a simple process using iron oxyhydroxide.

In order to achieve the above technical problem, the present invention comprises the steps of (a) immersing a material made of iron oxyhydroxide (FeOOH) in a mixed solution of water and lower alcohol containing Fe ²⁺ and Fe ³⁺ ; And (b) generating gaseous hydrogen by irradiating light to the material and the mixed solution made of the iron oxyhydroxide. It proposes a method for producing hydrogen using iron oxyhydroxide.

In addition, the iron oxyhydroxide proposes a hydrogen production method using iron oxyhydroxide, characterized in that the iron oxyhydroxide is α-iron oxyhydroxide, β-iron oxyhydroxide, δ-iron oxyhydroxide or γ-iron oxyhydroxide.

In addition, a method for producing hydrogen using iron oxyhydroxide is proposed, wherein the lower alcohol is methanol.

In addition, it proposes a hydrogen production method using iron oxyhydroxide, characterized in that the light is ultraviolet light.

In addition, a method for producing hydrogen using iron oxyhydroxide is proposed, wherein the hydroxy radical (·OH) generated by light irradiation in step (b) decomposes water and lower alcohol to generate hydrogen.

In addition, in the step (b), Fe ³⁺ is reduced to Fe ²⁺ and a hydroxy radical (OH) is generated according to the photo-Fenton reaction represented by the following reaction equation by light irradiation, A method for producing hydrogen using iron oxyhydroxide is proposed, characterized in that hydroxy radicals decompose water and lower alcohols to produce hydrogen:

(In the above formula, hν is the photon energy).

According to the hydrogen production method using iron oxyhydroxide according to the present invention, even if only light irradiation is performed without voltage application and light irradiation at the same time, hydroxy by photo-Fenton reaction on the surface of a material consisting of only iron oxyhydroxide. Hydrogen can be produced through decomposition of water and lower alcohol by generating radicals (OH), and the iron oxyhydroxide provided in the photofenton reaction is semi-permanently regenerated through a reaction with Fe ²⁺ solution or oxygen in the atmosphere. Radical generation and hydrogen production are possible.

In addition, since water treatment and energy production are possible only if an environment capable of light irradiation and iron oxyhydroxide contained in corroded iron that can be easily obtained anywhere is provided, it has a remarkable advantage compared to the conventional technology in terms of hydrogen production cost and process simplicity.

1 is a flowchart sequentially showing each step of a method for producing hydrogen using iron oxyhydroxide according to the present invention.
2(a) and 2(b) are scanning electron microscopy (SEM) pictures taken at different magnifications and XRD analysis results for α-FeOOH synthesized in the present example.
3(a) and 3(b) are scanning electron microscope (SEM) photographs taken at different magnifications and XRD analysis results for β-FeOOH synthesized in the present example.
4(a) and 4(b) are scanning electron microscope (SEM) photographs taken at different magnifications and XRD analysis results for γ-FeOOH synthesized in the present example.
5(a) and 5(b) are scanning electron microscope (SEM) photographs taken at different magnifications and XRD analysis results for δ-FeOOH synthesized in the present example.
6 is a graph showing the amount of hydrogen production according to UV irradiation time for α-iron oxyhydroxide, β-iron oxyhydroxide, δ-iron oxyhydroxide and γ-iron oxyhydroxide prepared in Examples.

In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Since the embodiments according to the concept of the present invention can apply various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiments according to the concept of the present invention to a specific form of disclosure, and it should be understood that all changes, equivalents, and substitutes included in the spirit and scope of the present invention are included.

The terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of a set feature, number, step, action, component, part, or combination thereof, but one or more other features or numbers It is to be understood that the possibility of addition or presence of, steps, actions, components, parts, or combinations thereof is not preliminarily excluded.

Hereinafter, the present invention will be described in detail.

As shown in Figure 1, the hydrogen production method using iron oxyhydroxide according to the present invention (a) a material made of iron oxyhydroxide (FeOOH), a mixed solution of water and lower alcohol containing Fe ²⁺ and Fe ³⁺ It characterized in that it comprises the steps (S100) and (b) irradiating light (light) to the material made of the iron oxyhydroxide and the mixed solution to generate gaseous hydrogen (S200).

In step (a), prior to performing the light irradiation step for hydrogen generation, a water/lower alcohol mixed solution containing Fe ²⁺ and Fe ³⁺ is prepared, and a material made of iron oxyhydroxide (FeOOH) is immersed in the mixed solution. Let it.

The iron oxyhydroxide is classified into α-iron oxyhydroxide, β-iron oxyhydroxide, δ-iron oxyhydroxide, γ-iron oxyhydroxide, etc., depending on its crystal structure, but in adopting iron oxyhydroxide used as a material for hydrogen production in the present invention The crystal structure is not particularly limited.

In addition, the shape of the material made of iron oxyhydroxide is not particularly limited, and in consideration of the control of hydrogen production according to the specific surface area, ease of handling, etc., in the form of a powder (0 dimensional), a tube or whisker (1 dimensional), a thin film ( It can take various forms, such as 2D) and bulk (3D).

On the other hand, the lower alcohol included in the water/lower alcohol mixed solution containing Fe ²⁺ and Fe ³⁺ is preferably an alcohol having 1 to 6 carbon atoms, and more preferably methanol.

In order to decompose water to obtain hydrogen, energy of 1.2 eV is theoretically required, but in practice more energy is required due to overpotential, whereas lower alcohols can generate hydrogen using much lower energy than water. .

For example, in the case of methanol, when two hydroxy radicals (OH) generated in the valence band in the presence of a photocatalyst meet one molecule of methanol, the following reaction proceeds to generate hydrogen, and the energy required for the reaction is about 0.6 eV. As compared to the case of water decomposition, about half of the energy is required, and accordingly, methanol decomposition reaction is accelerated, and hydrogen production can be greatly increased.

Next, in the step (b), in order to produce hydrogen by decomposing water and lower alcohol, light is irradiated to the material made of iron oxyhydroxide and the mixed solution.

In this step, hydroxy radicals (OH) generated by irradiating light in the wavelength range of ultraviolet or visible light to a material and a mixed solution made of iron oxyhydroxide decompose water and lower alcohols to generate hydrogen.

More specifically, when light is irradiated to a material made of iron oxyhydroxide and a mixed solution, Fe ³⁺ in the mixed solution is reduced to Fe ²⁺ according to the photo-Fenton reaction represented by the following reaction formula, and hydroxy A radical (·OH) is generated, and the hydroxy radical decomposes water and a lower alcohol to generate hydrogen.

(hν는 광자 에너지임)

(hν is photon energy)

In particular, in this step, unlike the prior art, it is not necessary to simultaneously apply voltage and light irradiation, and even if only light irradiation is performed, hydroxy radicals (OH) are generated through the photofenton reaction on the surface of the material consisting of only iron oxyhydroxide. Hydrogen can be produced through decomposition of alcohol, and since the iron oxyhydroxide provided in the photofenton reaction is regenerated through a reaction with a solution of Fe ²⁺ or oxygen in the atmosphere, radical generation and hydrogen production are possible semi-permanently.

In addition, since water treatment and energy production are possible only if an environment capable of light irradiation and iron oxyhydroxide contained in corroded iron that can be easily obtained anywhere is provided, it has a remarkable advantage compared to the conventional technology in terms of hydrogen production cost and process simplicity.

Hereinafter, the present invention will be described in more detail with reference to examples.

The embodiments according to the present specification may be modified in various forms, and the scope of the present specification is not construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely describe the present specification to those of ordinary skill in the art.

<Example>

1. Preparation of iron oxyhydroxide

(1) Synthesis of α-FeOOH

An aqueous ammonia solution was added dropwise to an aqueous solution containing 3.00 g of iron (II) sulfate (FeSO ₄ ㅇ7H ₂ O) in 100 ml of DI water, while adjusting the pH to 6.5ㅁ0.2, and then aged at 80°C for 4 hours, After drying at 60° C. for 12 hours, washing with deionized water and centrifugation were repeated three times, and then drying at 60° C. for 24 hours, α-FeOOH was obtained (FIGS. 2A and 2B ).

(2) Synthesis of β-FeOOH

An aqueous solution containing 3.00 g of PEG (10000) and 0.60 g of iron (III) chloride (FeCl ₃ ㅇ6H ₂ O) in 40 ml of DI water was subjected to hydrothermal treatment at 80° C. for 6 hours, followed by deionization. After repeating ion water washing and centrifugation three times, drying at 60° C. for 24 hours was completed to obtain β-FeOOH (FIGS. 3A and 3B ).

(3) Synthesis of γ-FeOOH

After dropping an aqueous solution of sodium hydroxide (NaOH) while adjusting the pH to 7.0 to an aqueous solution containing 0.50 g of EDTA and 0.50 g of iron (II) chloride (FeCl ₂ ㅇ4H ₂ O) to 100 ml of DI water, washing with deionized water And after repeating the centrifugation 3 times, drying at 60° C. for 24 hours was completed to obtain γ-FeOOH (FIGS. 4A and 4B).

(4) Synthesis of δ-FeOOH

Iron (II) ammonium sulfate (Fe(NH ₄ ) ₂ (SO ₄ ) ₂ ㅇ6H ₂ O) 3.00 g in 100 ml of DI water, 100 ml of 2M NaOH and 0.5 ml of 30% hydrogen peroxide (H ₂ O ₂ ) or After adding 1.5 ml, washing with deionized water and centrifugation were repeated 3 times, and then drying at 60° C. for 24 hours was completed to obtain δ-FeOOH (FIGS. 5A and 5B ).

2. Hydrogen production using synthesized iron oxyhydroxide

After adding 90 ml of deionized water (D.I. water) and 10 ml of methanol to a 190 ml volume triangular beaker, 50 mg of iron oxyhydroxide synthesized in the above 1. The triangular beaker uses optical fiber lighting to block the inside of the beaker from the outside and simultaneously irradiates light. The wavelength of light used was a UV wavelength of 400 nm or less.

6 is a result of measuring the amount of hydrogen production according to the UV irradiation time for each of the iron oxyhydroxide synthesized in 1., according to this, γ-iron oxyhydroxide, α-iron oxyhydroxide, β- at 48 hours after the start of UV irradiation. It was found that the order of iron oxyhydroxide and δ-iron oxyhydroxide showed high hydrogen production.

The present invention is not limited to the above embodiments, but may be manufactured in a variety of different forms, and a person of ordinary skill in the art to which the present invention pertains to other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that it can be implemented with. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting.

Claims (6)

(a) immersing a material made of iron oxyhydroxide (FeOOH) in a mixed solution of water and lower alcohol containing Fe ²⁺ and Fe ³⁺ ; And
(b) irradiating light to the material made of iron oxyhydroxide and the mixed solution to generate gaseous hydrogen; including,
Hydrogen production method using iron oxyhydroxide. The method of claim 1,
The iron oxyhydroxide is a hydrogen production method using iron oxyhydroxide, characterized in that α-iron oxyhydroxide, β-iron oxyhydroxide, δ-iron oxyhydroxide, or γ-iron oxyhydroxide. The method of claim 1,
Hydrogen production method using iron oxyhydroxide, characterized in that the lower alcohol is methanol. The method of claim 1,
Hydrogen production method using iron oxyhydroxide, characterized in that the light is ultraviolet light. The method of claim 1,
Hydrogen production method using iron oxyhydroxide, characterized in that the hydroxy radical (·OH) generated by light irradiation in the step (b) decomposes water and lower alcohol to produce hydrogen. The method of claim 5,
In the step (b), Fe ³⁺ is reduced to Fe ²⁺ according to the photo-Fenton reaction represented by the following reaction formula by light irradiation, and a hydroxy radical (OH) is generated, and the hydroxy Hydrogen production method using iron oxyhydroxide, characterized in that radicals decompose water and lower alcohols to produce hydrogen:

(In the above equation, hν is photon energy).

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