KR20220147948A - Water splitting material, composition for water splitting material and manufacturing method for water splitting material using the same - Google Patents

Abstract

The present invention relates to a water decomposition material, a composition for a water decomposition material and a manufacturing method of a water decomposition material using the same. In one embodiment, the water decomposition material includes an iron oxide-based activator and a calcium aluminate-based support having a spinel structure. The present invention is to provide the water decomposition material having excellent reactivity with water and hydrogen production efficiency.

Description

Water decomposition material, composition for water decomposition material, and method for manufacturing water decomposition material using the same

The present invention relates to a water-decomposing material, a composition for a water-decomposing material, and a method for manufacturing a water-decomposing material using the same.

Hydrogen is currently in the spotlight as an eco-friendly energy fuel for revitalizing a low-carbon economy and reducing greenhouse gases. The conventional hydrogen production method uses a reforming reaction using hydrocarbon-based fossil fuels, but this method produces carbon dioxide (CO ₂ ), a greenhouse gas, together with hydrogen and discharges them to the atmosphere. Therefore, in order to reduce the amount of carbon dioxide (CO ₂ ) emitted to the atmosphere during the hydrogen production process, a separate additional process such as carbon dioxide (CO ₂ ) capture and hydrogen purification is required at the rear end of the reforming process.

As an alternative technology to solve this problem, there is a hydrogen production technology through a chemical looping water splitting (CLWS) reaction using a material made of metal oxide. In this technology, as a material made of metal oxide is reduced by a reducing gas, the material emits oxygen and becomes a metal. Then, when water (H ₂ O), an oxidizing agent containing oxygen atoms, reacts, the metal material is oxidized to a metal oxide. and water is decomposed to produce high-purity hydrogen. In addition, after the oxidation reaction with water, an additional oxidation reaction may occur by reacting with an oxidizing agent such as oxygen or air. Therefore, this technology is a technology for producing hydrogen through repeated redox reactions of metals, and when a fuel containing carbon is used as a reducing agent, high-purity carbon dioxide can be separated and captured without a separate separation process during hydrogen production.

Hydrogen (H ₂ ), carbon monoxide (CO), methane (CH ₄ ) and hydrocarbon compounds may be used as the reducing agent, and in this case, metal oxide (MeO) is reduced through reduction reaction as shown in Formula A and water (H ₂ O) or carbon dioxide (CO ₂ ) is produced.

[Formula A]

Reduction reaction: MeO + C _x H _y O _z → Me + aCO ₂ + bH ₂ O

Therefore, carbon dioxide (CO ₂ ) that can be generated by the reduction reaction can capture high-purity carbon dioxide (CO ₂ ) only by condensation of water (H ₂ O) without a separate gas separation process, and the reduced material is obtained by the following formula B- As shown in 1 and Equation B-2, it reacts with oxygen atoms contained in water (H ₂ O) or air (Air) and is regenerated in the form of metal oxide (MeO) to return to its original form.

[Formula B-1]

Oxidation reaction: Me + H ₂ O → MeO + H ₂

[Formula B-2]

Me + O ₂ → 2MeO

At this time, since hydrogen can be generated only through an oxidation reaction with water (H ₂ O) as shown in Formula B-1, in a process where hydrogen production is the main purpose, the performance is performed in the oxidation reaction with water (H ₂ O) after reduction The development of this excellent metal oxide-based material is an important factor.

In particular, water decomposition materials using iron oxide are known to have excellent hydrogen production capacity due to their excellent reactivity with water. However, the water decomposition material using iron oxide undergoes a stepwise oxidation/reduction reaction as shown in Formula C below, and exists in the air in various forms such as ferric trioxide, triiron tetraoxide, and iron oxide hydrate. Therefore, it is important to optimize the composition of the water decomposition material by selecting the most suitable iron oxide to be used in hydrogen production technology.

[Formula C]

Fe ₂ O ₃ ↔ Fe ₃ O ₄ ↔ FeO ↔ Fe

Background art related to the present invention is disclosed in Japanese Patent Publication No. 6048951 (published on December 21, 2016, title of the invention: high active oxygen carrier material of chemical loop method).

One object of the present invention is to provide a water decomposition material that is excellent in thermal stability, durability and long-term performance, and can prevent performance degradation during repeated redox reactions at high temperatures.

Another object of the present invention is to provide a water decomposition material having excellent reactivity with water and hydrogen production efficiency.

Another object of the present invention is to provide a composition for the water decomposition material.

Another object of the present invention is to provide a method for manufacturing a water decomposing material using the composition for water decomposing material.

Another object of the present invention is to provide a method for producing hydrogen using the water decomposition material.

One aspect of the present invention relates to a water decomposition material. In one embodiment, the water-decomposing material includes an iron oxide-based active material and a calcium aluminate-based support having a spinel structure.

In one embodiment, the water decomposition material may include 60 to 90% by weight of the iron oxide-based active material and 10 to 40% by weight of the support.

In one embodiment, the iron oxide-based activator may include an iron oxide of Formula 1 below:

[Formula 1]

Fe _a O _b H _c

(In Formula 1, a is 2 or 3, b is 3 or 4, and c is 0 or 2).

In one embodiment, the iron oxide-based activator may be needle-shaped or spherical.

In one embodiment, the iron oxide-based active material may include needle-shaped ferric trioxide hydrate (Fe ₂ O ₃ ·H ₂ O) having a specific surface area of 40 m ² /g or more.

In one embodiment, the iron oxide-based active material may include at least one of spherical ferric trioxide (Fe ₂ O ₃ ) and triiron tetraoxide (Fe ₃ O ₄ ) having a specific surface area of 7 m ² /g or more.

In one embodiment, the water decomposition material is a mixed gas (flow rate 100 l/min) containing hydrogen and nitrogen in a 1:9 volume ratio and a reduction reaction (950°C, 30 minutes), followed by water and nitrogen in a 1:9 volume ratio In an oxidation-reduction reaction in which one cycle of oxidation reaction (950 ° C., 20 minutes) with a mixed gas containing

[Equation 1]

Oxidation amount (wt%) = [(W ₂ -W ₁ )/W ₁ ] * 100

(In Equation 1, W ₁ is the initial mass of the water decomposing material, and W ₂ is the mass of the water decomposing material measured after 20 cycles).

Another aspect of the present invention relates to the composition for the water decomposition material. In one embodiment, the composition for a water-decomposing material comprises: a solid raw material comprising an iron oxide-based active material and a calcium aluminate-based support having a spinel structure; dispersant; and an organic binder.

In one embodiment, the composition for a water decomposition material comprises 100 parts by weight of a solid raw material, 1 to 10 parts by weight of a dispersant, and 1 to 10 parts by weight of an organic binder, and the solid raw material is 60 to 90% by weight of an iron oxide-based active material and It may include 10 to 40% by weight of the support.

In one embodiment, the iron oxide-based activator may include an iron oxide of Formula 1 below:

[Formula 1]

Fe _a O _b H _c

(In Formula 1, a is 2 or 3, b is 3 or 4, and c is 0 or 2).

In one embodiment, the dispersant may include an anionic dispersant, and the organic binder may include a glycol-based binder.

In one embodiment, it may further include more than 0 and 500 parts by weight or less of a solvent based on 100 parts by weight of the solid raw material.

Another aspect of the present invention relates to a method for manufacturing a water decomposing material using the composition for water decomposing material. In one embodiment, the method for producing the water decomposition material comprises the steps of preparing a first mixture comprising a solid raw material; preparing a second mixture including the first mixture, a dispersant, and an organic binder; drying and filtering the second mixture to obtain a filtrate; and calcining the filtrate, wherein the solid raw material includes an iron oxide-based active material and a calcium aluminate-based support having a spinel structure.

In one embodiment, the second mixture is prepared by adding a dispersing agent to the first mixture and stirring at 400 to 650 rpm; And adding an organic binder to the first agitated material, and the step of secondary stirring at 400 ~ 650rpm; can be prepared including.

In one embodiment, the drying may be carried out at 120 °C or higher.

In one embodiment, the calcination, the filtrate is maintained by raising the temperature stepwise at a temperature increase rate of 3 to 8 °C/min at intervals of 100 °C from 200 °C, and maintaining the temperature by raising the temperature to 800 to 1500 °C; can

Another aspect of the present invention relates to a hydrogen production method using the water decomposition material. In one embodiment, the method for producing hydrogen using the water decomposing material comprises the steps of reacting the water decomposing material with a reducing gas to reduce the water decomposing material and generating water; and reacting the reduced water decomposing material with water to generate hydrogen and oxidizing the water decomposing material.

In one embodiment, the method may further include: reacting the water decomposing material oxidized with water with an oxidizing gas to regenerate the water decomposing material.

The water decomposition material according to the present invention has excellent thermal stability, durability, and long-term performance, so it is possible to prevent performance degradation during repeated redox reactions at high temperatures, and has excellent reactivity with water, especially after a high temperature reduction reaction. It has excellent oxidation reactivity and hydrogen production efficiency.

1 shows a method for manufacturing a water decomposition material according to an embodiment of the present invention.

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

And the terms described below are terms defined in consideration of functions in the present invention, which may vary depending on the intention or custom of the user or operator, so the definition should be made based on the content throughout this specification describing the present invention.

water decomposition material

One aspect of the present invention relates to a water decomposition material. In one embodiment, the water decomposition material is an iron oxide-based active material; and a calcium aluminate-based support.

The iron oxide-based activator directly participates in the chemical roofing type water decomposition reaction, and the chemical form may change during the water decomposition reaction process.

In one embodiment, the iron oxide-based activator may include an iron oxide of Formula 1 below:

[Formula 1]

Fe _a O _b H _c

(In Formula 1, a is 2 or 3, b is 3 or 4, and c is 0 or 2).

When iron oxide satisfying the conditions of Formula 1 is included, the oxygen transfer efficiency, durability, and long-term performance of the water decomposition material may be reduced.

In one embodiment, the iron oxide-based activator is Fe ₂ O ₃ (a=2, b=3, c=0) called ferric trioxide or red iron oxide; Fe ₂ O ₃ ·H ₂ O (a=2, b=4, c=2), also called ferric trioxide hydrate or yellow iron oxide; and Fe ₃ O ₄ (a=3, b=4, c=0), also called ferric tetraoxide or black iron oxide; It may include one or more of The iron oxide-based activator of the above type may have different colors at room temperature, so it may be possible to distinguish them with the naked eye.

In one embodiment, the iron oxide-based active material may have an average size of 17 μm or less. The average size may mean a “maximum length” or “diameter” of the iron oxide-based active material. Under the above conditions, the reaction efficiency, durability, and long-term performance of the water-decomposing material at high temperature may be excellent. For example, the iron oxide-based active material may have an average size greater than 0 and 16.5 μm. For another example, it may be 3 ~ 15㎛.

In one embodiment, the iron oxide-based active material may be needle-shaped or spherical. In the above form, the reactivity of the water-decomposing material may be excellent.

In one embodiment, the iron oxide-based active material may include needle-shaped ferric trioxide hydrate (Fe ₂ O ₃ ·H ₂ O) having a specific surface area of 40 m ² /g or more. When the needle-shaped ferric trioxide hydrate of the specific surface area condition is included, the surface area is higher than that of the spherical iron oxide-based active material, so that the contact area with the gaseous oxidizing agent and the reducing agent in the surface reaction step of the water decomposition reaction is increased. Reactivity is further improved, durability is excellent, and reactivity degradation is minimized even in repeated oxidation-reduction reactions at high temperatures, so that long-term reactivity can be excellent. For example, the specific surface area may be 40 to 200 m ² /g.

In another embodiment, the iron oxide-based active agent may include at least one of spherical ferric trioxide having a specific surface area of 7 m ² /g or more and spherical triiron tetraoxide having a specific surface area of 7 m ² /g or more. Under the above conditions, the reactivity, durability and long-term reactivity of the water-decomposing material at high temperature may be excellent. The spherical ferric trioxide and tetraoxide may have a specific surface area of 7 to 20 m ² /g.

The iron oxide-based activator may be included in an amount of 50 to 90% by weight based on the total weight of the water-decomposing material. When included under the above conditions, the reactivity, durability and long-term reactivity of the water-decomposing material at high temperatures may be excellent. For example, 65 to 75% by weight may be included.

The calcium aluminate-based support having the spinel structure may include a porous structure that imparts strength and structural stability to the water-decomposing material, and allows the iron oxide-based active material to be uniformly dispersed. In one embodiment, the support of the spinel structure may include at least one of calcium aluminate (CaAl ₂ O ₄ ) and dicalcium aluminate (Ca ₂ Al ₂ O ₅ ). When the support is included, the iron oxide-based active material is easily dispersed, and the stability, strength and thermal stability of the water-decomposing material may be excellent.

In one embodiment, the support may be included in an amount of 10 to 40% by weight based on the total weight of the water decomposing material. When included in the above range, the strength and thermal stability and long-term performance of the water-decomposing material may be excellent. For example, 25 to 35% by weight may be included.

In one embodiment, the water decomposition material is a mixed gas (flow rate 100 l/min) containing hydrogen (H ₂ ) and nitrogen (N ₂ ) in a volume ratio of 1:9 and a reduction reaction (950 ° C., 30 minutes), followed by water (or water vapor, H ₂ O) and nitrogen (N ₂ ) Oxidation-reduction reaction in which one cycle of oxidation reaction (950 ° C, 20 minutes) with a mixed gas (flow rate 100 l/min) containing nitrogen (N 2 ) in a volume ratio of 1:9 In , the oxidation amount after the 20th cycle oxidation reaction represented by the following formula 1 may be 16 wt% or more (16 g or more oxidation in 100 g of the water decomposition material):

[Equation 1]

Oxidation amount (wt%) = [(W ₂ -W ₁ )/W ₁ ] * 100

(In Equation 1, W ₁ is the initial mass of the water decomposing material, and W ₂ is the mass of the water decomposing material measured after 20 cycles).

In one embodiment, the amount of oxidation of the water decomposing material can be calculated as a percentage of the increase in the mass according to the oxidation reaction relative to the initial mass, as shown in Equation 1-1:

[Equation 1-1]

The oxidation amount according to Equation 1 may be measured using thermogravimetric analysis (TGA).

The long-term stability of the water-decomposing material of the present invention may be excellent under the oxidation amount condition of Equation 1 above. For example, the oxidation amount according to Equation 1 may be 16 to 20 wt%. The water-decomposing material of the present invention has excellent long-term stability, so that the oxidation amount according to Equation 1 satisfies 16% by weight or more, and the reduction in the amount of oxidation of the water-decomposing material can be minimized even when the oxidation-reduction reaction is repeated.

Composition for water decomposition material

Another aspect of the present invention relates to a composition for a water decomposing material for producing the water decomposing material. In one embodiment, the composition for a water-decomposing material comprises: a solid raw material comprising an iron oxide-based active material and a calcium aluminate-based support having a spinel structure; dispersant; and an organic binder.

In one embodiment, the average size of the raw material mixture after stirring or pulverizing the raw material for the composition for water decomposition material may be 17 μm or less.

Since the solid raw material may be the same as that described above, a description thereof will be omitted.

The solid raw material may include 60 to 90% by weight of the iron oxide-based active material and 10 to 40% by weight of the support. When included under the above conditions, the reactivity, durability and long-term reactivity of the water-decomposing material at high temperatures may be excellent. For example, the solid raw material may include 65 to 75% by weight of the iron oxide-based active material and 25 to 35% by weight of the support.

The dispersant may include an anionic dispersant. When the dispersing agent is included, the dispersibility of the iron oxide-based active material and the mixing property of the composition are excellent, and thus the reaction efficiency may be excellent. For example, the anionic dispersant may include at least one of an ammonium polycarboxylic acid salt, a polycarboxylic acid sodium salt, and a polycarboxylic acid potassium salt.

In one embodiment, the dispersant may be included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the solid raw material. When included in the above range, the dispersibility of the iron oxide-based active material and the mixing property of the composition may be excellent. For example, 1 to 6 parts by weight may be included.

The organic binder may serve to provide mechanical strength of the water-decomposing material by easily bonding the solid raw material including the active material and the support to each other during the manufacturing process of the composition.

In one embodiment, the organic binder may include a glycol-based binder. When the glycol-based binder is included, the composition may have excellent mixing properties, and mechanical strength such as durability of the water-decomposable material may be excellent. For example, the glycol-based binder may include one or more of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol.

In one embodiment, the organic binder may be included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the solid raw material. When included in the above range, the dispersibility of the iron oxide-based active material and the mixing property of the composition may be excellent. For example, 1 to 6 parts by weight may be included.

In one embodiment, the composition for water decomposition material may further include a solvent. When the solvent is included, the mixability and dispersibility of the composition may be excellent.

In one embodiment, the solvent may include at least one of water, an aromatic hydrocarbon-based compound, an ether-based compound, and an alcohol-based compound. For example, it may include water.

In one embodiment, the aromatic hydrocarbon-based compound may include at least one of toluene, benzene, xylene, tetrahydrofuran (THF), and N-methyl-2-pyrrolidone (NMP).

In one embodiment, the ether-based compound is 3-methoxybutanol, methyl cellosolve (ethylene glycol monomethyl ether), ethylene glycol monoethyl ether (cellosolve), butyl cellosolve (ethylene glycol monobutyl ether), carr It may include at least one of bitol (diethylene glycol monoethyl ether), butyl carbitol (diethylene glycol monobutyl ether), and propylene glycol monomethyl ether.

In one embodiment, the alcohol-based compound may include at least one of ethanol, methanol, butanol, isobutanol, and isopropyl alcohol.

In one embodiment, the solvent may be included in more than 0 and 500 parts by weight or less based on 100 parts by weight of the solid raw material. When included under the above conditions, the active material of the solid raw material is easily dispersed on the surface of the support, the composition has excellent mixability and dispersibility, and the activation efficiency of the water-decomposing material can be increased. For example, 30 to 200 parts by weight may be included.

The oxidation-reduction reaction for hydrogen production using iron oxide-based metal materials takes place at a high temperature of 500°C or higher. However, at a high temperature of 500° C. or higher, the aggregation of iron (Fe)-based oxides is accelerated, and the long-term performance and durability of the material deteriorate in the repeated oxidation-reduction reaction. Therefore, in order to increase hydrogen production and improve the efficiency of the reaction process, it is necessary to develop a water decomposition material using an iron oxide-based material that maintains excellent performance even in repeated oxidation-reduction reactions at high temperatures as an activator.

In the present invention, iron oxide-based (Fe _a O _b H _c /a = 2,3, b = 3,4, c = 0,2) material is applied as an activator, and a spinel structure with excellent physicochemical stability at high temperature Calcium aluminate-based compound (CaAl ₂ O ₄ , Ca ₂ Al ₂ O ₅ ) is applied as a support and has excellent reactivity with water (H ₂ O) during oxidation-reduction reactions that are repeatedly performed at a temperature of 950° C. or higher for 20 or more times. Thus, the optimal composition and mass production of materials with excellent oxygen delivery amount and thermal stability and with insignificant degree of deactivation as the reaction proceeds may be possible.

Method for manufacturing water decomposing material using composition for water decomposing material

Another aspect of the present invention relates to a method for manufacturing a water decomposing material using the composition for water decomposing material. 1 shows a method for manufacturing a water decomposition material according to an embodiment of the present invention. Referring to FIG. 1 , the method for manufacturing a water decomposition material includes (S10) a first mixture preparation step; (S20) preparing a second mixture; (S30) obtaining a filtrate; and (S40) a firing step.

More specifically, the method for producing a water decomposition material comprises the steps of (S10) preparing a first mixture containing a solid raw material; (S20) preparing a second mixture including the first mixture, a dispersant, and an organic binder; (S30) drying and filtering the second mixture to obtain a filtrate; and (S40) calcining the filtrate.

(S10) first mixture preparation step

The step is a step of preparing a first mixture containing the solid raw material. For example, the first mixture may include a solid raw material including an iron oxide-based active material and a calcium aluminate-based support having a spinel structure, and a first mixture including a solvent.

The iron oxide-based activator, the support, and the solvent may be the same as those described above.

The solid raw material includes an iron oxide-based active material and a calcium aluminate-based support having a spinel structure.

In one embodiment, the support of the spinel structure may include at least one of calcium aluminate (CaAl ₂ O ₄ ) and dicalcium aluminate (Ca ₂ Al ₂ O ₅ ).

In one embodiment, the solvent may be included in an amount greater than 0 to 500 parts by weight based on 100 parts by weight of the solid raw material. When included under the above conditions, the active material of the solid raw material is easily dispersed on the surface of the support, and the mixing and dispersibility of the first mixture is excellent, and the activation efficiency of the water decomposing material can be increased. For example, 30 to 200 parts by weight may be included.

(S20) second mixture preparation step

The step is a step of preparing a second mixture including the first mixture, the dispersant and the organic binder.

The dispersant and the organic binder may be the same as those described above.

In one embodiment, the dispersant may be included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the solid raw material. When included in the above range, the dispersibility of the iron oxide-based active material and the mixing property of the composition may be excellent. For example, 1 to 6 parts by weight may be included.

In one embodiment, the organic binder may be included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the solid raw material. When included in the above range, the dispersibility of the iron oxide-based active material and the mixing property of the composition may be excellent. For example, 1 to 6 parts by weight may be included.

In one embodiment, the second mixture is prepared by adding a dispersant of the above-described content to the first mixture and stirring (or pulverizing) at 400 to 650 rpm; And adding the organic binder of the above-described content to the first stirring material and secondary stirring (or grinding) at 400 to 650 rpm; may be prepared including. Under the above conditions, the mixability and dispersibility during primary stirring and secondary stirring or pulverization are excellent, so that the durability and mechanical properties of the water decomposition material are excellent, and hydrogen production efficiency and long-term reactivity can be excellent.

(S30) step of obtaining the filtrate

The step is a step of drying and filtering the second mixture to obtain a filtrate. In one embodiment, the drying may be performed by drying the second mixture at 120° C. or higher. Under the above conditions, the moisture of the second mixture is easily evaporated, and the durability and mechanical properties of the water-decomposing material are excellent, and long-term reactivity may be excellent. For example, it can be dried at 120 ~ 200 ℃ for 10 ~ 30 hours.

(S40) firing step

The step is a step of calcining the filtrate. In one embodiment, the sintering may be carried out at 800 to 1500 °C. Under the above conditions, the mechanical strength of the water-decomposing material may be excellent, and the reaction efficiency may be excellent.

In one embodiment, the calcination, but raising and maintaining the temperature of the filtrate at a temperature increase rate of 3 to 8 ° C / min step by step at intervals of 100 ° C. have. Under the above conditions, the mechanical strength of the water-decomposing material may be excellent, and the reaction efficiency may be excellent.

For example, the calcination may be carried out by raising and maintaining the temperature of the filtrate at a temperature increase rate of 5-8°C/min step by step at intervals of 100°C from 200°C, raising the temperature to 800-1500°C and maintaining it for 10-20 hours. can When calcined under the above conditions, the mechanical strength of the water decomposition material may be excellent, and hydrogen production efficiency and reaction efficiency may be excellent.

Hydrogen production method using water decomposition material

Another aspect of the present invention relates to a hydrogen production method using the water decomposition material. Or, it relates to a hydrogen production method using the chemical roof combustion using the water decomposition material.

In one embodiment, the method for producing hydrogen using the water decomposing material comprises the steps of reacting the water decomposing material with a reducing gas to reduce the water decomposing material and generating water; and reacting the reduced water decomposing material with water to generate hydrogen and oxidizing the water decomposing material.

In one embodiment, the reducing gas may include at least one of hydrogen (H ₂ ), carbon monoxide (CO), methane (CH ₄ ), and hydrocarbon compounds.

In one embodiment, the method may further include: reacting the water decomposing material oxidized with water with an oxidizing gas to regenerate the water decomposing material.

In one embodiment, the oxidizing gas may include oxygen or air.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and cannot be construed as limiting the present invention in any sense. Content not described here will be omitted because it can be technically inferred sufficiently by those skilled in the art.

Examples and Comparative Examples

Example 1

(1) Preparation of the first mixture: 70 wt% of ferric trioxide (Fe ₂ O ₃ ) and a spinel structure support (calcium aluminate (CaAl ₂ O ₄ )) 30 wt. % was mixed with 100 parts by weight of a solid raw material and 30 to 200 parts by weight of a solvent (distilled water) to prepare a first mixture.

(2) Preparation of second mixture: 100 parts by weight of the solid raw material and 2 parts by weight of a dispersant (ammonium polycarboxylic acid salt) were added to the first mixture, and stirred at 400 to 650 rpm to prepare a first stirred product. Then, 3 parts by weight of an organic binder (polyethylene glycol) was added to the first stirred water based on 100 parts by weight of the solid raw material, and stirred at 400 to 650 rpm to prepare a second mixture.

(3) Obtaining filtrate: The second mixture was dried in an air atmosphere reflux dryer at 120 to 200° C. for 24 hours, and filtered through a sieve to obtain a filtrate having a size of 53 to 150 μm.

(4) Firing: The filtrate was heated and maintained at a temperature increase rate of 5 °C/min step by step at intervals of 100 °C from 200 °C, but the temperature was raised to 1000 °C and held for 12 hours and calcined to prepare a water decomposition material.

Example 2

A water-decomposable material was prepared in the same manner as in Example 1, except that dicalcium aluminate (Ca ₂ Al ₂ O ₅ ) of Table 2 below was applied as a support.

Comparative Example 1

A water-decomposing material was prepared in the same manner as in Example 1, except that alumina (Al ₂ O ₃ ) of Table 2 was applied as a support.

Example 3

A water-decomposing material was prepared in the same manner as in Example 1, except that triiron tetraoxide (Fe ₄ O ₃ ) of the conditions in Table 1 below was applied as an activator.

Example 4

A water-decomposing material was prepared in the same manner as in Example 3, except that the support of the following Table 3 conditions was applied.

Comparative Example 2

A water-decomposing material was prepared in the same manner as in Example 3, except that alumina (Al ₂ O ₃ ) of Table 3 was applied as a support.

Examples 5-6

Water in the same manner as in Example 1, except that 60 wt% of ferric trioxide hydrate (Fe ₂ O ₃ ·H ₂ O) active material under the conditions of Table 1 below and 40 wt% of support under the conditions of Table 4 below were applied as solid raw materials. A decomposition material was prepared.

Comparative Examples 3 to 10

A water-decomposable material was prepared in the same manner as in Example 5, except that the support in Table 4 conditions was applied.

Examples 7-8

A water-decomposable material was prepared in the same manner as in Example 5, except that 70% by weight of the activator and 30% by weight of the support according to the conditions in Table 5 were applied.

Comparative Example 11

Example 7 above, except that 30 wt% of the support of the following Table 5 conditions was applied, and the composition ratio of calcium oxide and alumina of calcium aluminate (CaO 50 mol% and Al ₂ O ₃ 50 mol%) was applied to be the same. A water-decomposing material was prepared in the same manner as in

Comparative Example 12

30% by weight of the support of the following Table 5 conditions was applied, except that the composition ratio of calcium oxide and alumina of dicalcium aluminate (CaO 67 mol% and Al ₂ O ₃ 33 mol%) was applied to be the same as the above Examples A water decomposition material was prepared in the same manner as in 8.

Experimental example

Long-term reaction performance evaluation: For the water decomposition materials prepared in Examples 1 to 8 and Comparative Examples 1 to 12, long-term reaction performance was evaluated. Specifically, with respect to the water decomposition material (initial mass: 10 mg), a mixed gas (flow rate 100 l/min) containing hydrogen (H ₂ ) and nitrogen (N ₂ ) in a 1:9 volume ratio and a reduction reaction (950 ° C., 30 minutes), followed by an oxidation reaction (950°C, 20 minutes) with a mixed gas (flow rate 100 l/min) containing water (or water vapor, H ₂ O) and nitrogen (N ₂ ) in a 1:9 volume ratio 1 The oxidation-reduction reaction according to the cycle was repeated, and the oxidation amount after the oxidation reaction at the 5th cycle and the 20th cycle represented by the following formula 1 was measured using thermogravimetric analysis. At the end of the oxidation-reduction reaction of each cycle, pure nitrogen gas was flowed for 5 to 10 minutes to remove residual gas that may exist in the water decomposition material and the reaction device, and 20 cycles were performed after 5 cycles After calculating the amount of oxidation decrease, the results are shown in Tables 6 to 9:

[Equation 1]

Oxidation amount (wt%) = [(W ₂ -W ₁ )/W ₁ ] * 100

(In Equation 1, W ₁ is the initial mass (mg) of the water decomposing material, and W ₂ is the mass (mg) of the water decomposing material measured after 5 cycles and 20 cycles).

Referring to the results of Tables 6 to 9, the water decomposition materials of Examples 1 to 4 are comparative examples 1 to which generally widely used alumina (Al ₂ O ₃ ) is applied as a support for chemical reaction materials such as catalysts and adsorbents. It can be seen that the performance of the measured oxidation amount after 5 cycles and 20 cycles is improved from a minimum of 9 wt% to a maximum of 13 wt% compared to 3, and it can be seen that the reduction amount of the oxidation amount is very excellent compared to Comparative Examples 1 to 3.

In Examples 5-6, it can be seen that the oxidation amount measured after 5 cycles and 20 cycles improved by at least 1.5 wt% to a maximum of 4 wt% compared to Comparative Examples 4 to 10 to which an alumina support having a spinel structure different from the present invention was applied. and it can be seen that the amount of oxidation reduction is very excellent compared to Comparative Examples 4 to 10.

In addition, in Examples 7 and 8, compared to Comparative Examples 11 to 12 to which a support having the same calcium oxide and alumina component ratio was applied, the oxidation amount measured after 5 cycles and 20 cycles was at least 1.7% by weight and up to 3% by weight. could see that

Therefore, a water-decomposing material was prepared in the composition range presented in the present invention by using an iron oxide-based activator and a calcium aluminate-based single spinel structure (CaAl ₂ O ₄ and Ca ₂ Al ₂ O ₅ ) as a support. By doing so, it was confirmed that the oxygen delivery amount and long-term stability of the water decomposition material were improved at a high temperature of 900°C or higher.

Up to now, the present invention has been mainly examined in the examples. Those of ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments are to be considered in an illustrative rather than a restrictive sense. The scope of the present invention is indicated in the claims rather than the foregoing description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims (18)

A water decomposition material comprising an iron oxide-based active material and a calcium aluminate-based support having a spinel structure.
The water-decomposing material according to claim 1, wherein the water-decomposing material comprises 60 to 90% by weight of the iron oxide-based active material and 10 to 40% by weight of the support.
[Claim 2] The water decomposition material according to claim 1, wherein the iron oxide-based active material comprises an iron oxide represented by the following formula (1):
[Formula 1]
Fe _a O _b H _c
(In Formula 1, a is 2 or 3, b is 3 or 4, and c is 0 or 2).
The water-decomposing material according to claim 1, wherein the iron oxide-based active material is needle-shaped or spherical.
The water decomposition material according to claim 1, wherein the iron oxide-based active material comprises needle-shaped ferric trioxide hydrate (Fe ₂ O ₃ ·H ₂ O) having a specific surface area of 40 m ² /g or more.
The water decomposition according to claim 1, wherein the iron oxide-based active material comprises at least one of spherical ferric trioxide (Fe ₂ O ₃ ) and triiron tetraoxide (Fe ₃ O ₄ ) having a specific surface area of 7 m ² /g or more. Material.
The method according to claim 1, wherein the water decomposition material is a mixed gas (flow rate 100 l/min) containing hydrogen and nitrogen in a volume ratio of 1:9 and a reduction reaction (950°C, 30 minutes), followed by water and nitrogen in a ratio of 1:9 In an oxidation-reduction reaction in which one cycle is performed with a mixed gas (flow rate 100 l/min) and an oxidation reaction (950°C, 20 minutes) containing in a volume ratio,
Water decomposition material, characterized in that the oxidation amount after 20 cycles represented by the following formula 1 is 16 wt% or more:
[Equation 1]
Oxidation amount (wt%) = [(W ₂ -W ₁ )/W ₁ ] * 100
(In Equation 1, W ₁ is the initial mass of the water decomposing material, and W ₂ is the mass of the water decomposing material measured after 20 cycles).
a solid raw material comprising an iron oxide-based active material and a calcium aluminate-based support having a spinel structure;
dispersant; and
An organic binder; a composition for water decomposition material comprising a.
According to claim 8, wherein the composition for water decomposition material,
100 parts by weight of solid raw material,
1 to 10 parts by weight of a dispersant and
Contains 1 to 10 parts by weight of organic binder,
The solid raw material is a composition for water decomposition material, characterized in that it comprises 60 to 90% by weight of the iron oxide-based active material and 10 to 40% by weight of the support.
The composition for a water decomposition material according to claim 8, wherein the iron oxide-based active material comprises an iron oxide represented by the following formula (1):
[Formula 1]
Fe _a O _b H _c
(In Formula 1, a is 2 or 3, b is 3 or 4, and c is 0 or 2).
9. The method of claim 8, wherein the dispersant comprises an anionic dispersant,
The organic binder is a water-decomposing material composition comprising a glycol-based binder.
The composition for a water decomposing material according to claim 8, further comprising more than 0 and 500 parts by weight or less of a solvent based on 100 parts by weight of the solid raw material.
preparing a first mixture including a solid raw material;
preparing a second mixture including the first mixture, a dispersant, and an organic binder;
drying and filtering the second mixture to obtain a filtrate; and
Including; calcining the filtrate;
The solid raw material is a water-decomposing material manufacturing method, characterized in that it comprises an iron oxide-based active material and a calcium aluminate-based support having a spinel structure.
14. The method of claim 13, wherein the second mixture is prepared by adding a dispersant to the first mixture and stirring at 400 to 650 rpm to prepare a first stirring; and
A method for producing a water decomposing material, characterized in that it is prepared including; adding an organic binder to the first stirring material and second stirring at 400 to 650 rpm.
The method of claim 13, wherein the drying is carried out at 120° C. or higher.
14. The method of claim 13, wherein the calcination, the filtrate is maintained by raising the temperature stepwise at a rate of 3 to 8 °C/min at intervals of 100 °C from 200 °C, raising and maintaining the temperature to 800 to 1500 °C; Water decomposition material manufacturing method, characterized in that it comprises.
Claims 1 to 7 by reacting the water decomposition material and a reducing gas of any one of claims 1 to 7, reducing the water decomposition material and generating water; and
Hydrogen production method comprising a; generating hydrogen by reacting the reduced water decomposing material with water and oxidizing the water decomposing material.
18. The method of claim 17, further comprising the step of reacting the water decomposing material oxidized with water with an oxidizing gas to regenerate the water decomposing material.

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