JP2019195795A - Catalyzer and fuel reformer - Google Patents

Abstract

To provide a catalyzer capable of promoting production of Hgas and production of Ogas, and enhancing catalyst stabilizer, and a fuel performer using the same.SOLUTION: A catalyzer 1 has oxide 11 represented by LnMAO, wherein Ln:rare earth element, M:transition metal element, A:at least one kind of transition metal element different from noble metal element and the M, 0.03≤x≤0.1, 0.1≤y<0.5, and 2≤z≤4. The catalyzer 1 further has a noble element 12 carried on a surface of the oxide 11. A fuel modifier 2 has a reactor 21, the catalyzer 1 accommodated in the reactor 21, a heat source 22 for heating the catalyzer 1, an electric field application part 23 for applying an electric field to the catalyzer 1, and a control part 24 for changing supply and supply stop of a fuel containing at least H and O into the reactor, and controlling the electric field for applying to the catalyzer 1 by the electric field application part 23.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a catalyst body and a fuel reformer.

Conventionally, Patent Document 1 discloses a catalyst body capable of promoting both generation of H ₂ gas by thermal decomposition of water as fuel and release of O ₂ gas using oxygen trapped during the thermal decomposition of water. as _a catalyst having an oxide mixture of Ce _{0.5 Zr 0.5 O 2} and _Co 3 _{O 4} and _V 2 _{O 5} and MnO ₂ are disclosed. The device for generating H ₂ gas, O ₂ gas using the catalyst are described.

JP 2017-47405 A

However, in the conventional oxide mixture, during thermal decomposition of water, different elements in the mixed oxide, for example, Ce and V are complexed, and a different phase is precipitated. Therefore, the conventional oxide mixed, generation of H ₂ gas fuel reforming, although it is possible to prompt the release of O ₂ gas, catalyst stability is poor, there is a problem that it is difficult to repeatedly use .

The present invention has been made in view of such a problem, and a catalyst body that can promote generation of H ₂ gas and generation of O ₂ gas and improve catalyst stability, and also uses the same. The present invention intends to provide a fuel reforming apparatus.

One embodiment of the present invention includes Ln _(1- yx ₎ M _y A _x O _z (where Ln: rare earth element, M: transition metal element, A: noble metal element, and transition metal element different from M above) The catalyst body (1) has at least one oxide (11) represented by 0.03 ≦ x ≦ 0.1, 0.1 ≦ y <0.5, 2 ≦ z ≦ 4).

Another aspect of the present invention comprises a reactor (21),
The catalyst body (1) housed in the reactor;
A heat source (22) for heating the catalyst body;
An electric field application unit (23) for applying an electric field to the catalyst body;
A control unit (switching between supply of fuel containing at least one of hydrogen atoms and oxygen atoms into the reactor and supply stop of the fuel and controlling an electric field applied to the catalyst body by the electric field application unit ( 24)
In the fuel reformer (2).

The catalyst body has the oxide. In the oxide, the valence balance is destabilized and lattice distortion is likely to occur, and the valence of the constituent elements constituting the oxide is likely to change. Therefore, the oxide itself can fluctuate in valence and can selectively carry out two reactions of oxidation and reduction. Therefore, for example, when a fuel containing hydrogen atoms such as water and oxygen atoms is brought into contact with the catalyst body and an electric field is applied, polarization in the oxide is induced, and H ₂ gas is generated by the decomposition of the fuel. In addition, an oxidation reaction such as trapping oxygen and a reduction reaction such as releasing O ₂ gas using the trapped oxygen can be selectively performed. In addition, even when the above oxide is exposed to a hydrogen environment or an electric field is applied, heterogeneous formation by different elements hardly occurs and the crystal structure hardly changes. Therefore, the catalyst body has higher catalyst stability than the conventional catalyst body. Therefore, according to the above catalyst body, generation of H ₂ gas and generation of O ₂ gas can be promoted, and catalyst stability can be improved.

The fuel reformer includes the catalyst body that can promote the generation of H ₂ gas and O ₂ gas and has high catalyst stability. Therefore, according to the fuel reformer, H ₂ gas and O ₂ gas can be generated by repeatedly using the catalyst body.

  In addition, the code | symbol in the parenthesis described in the means to solve a claim and a subject shows the correspondence with the specific means as described in embodiment mentioned later, and limits the technical scope of this invention. It is not a thing.

2 is an explanatory view schematically showing a catalyst body of Embodiment 1. FIG. 6 is an explanatory view schematically showing a catalyst body of Embodiment 2. FIG. It is an explanatory view for explaining a fuel reforming method according catalyst embodiment 2, (a) is H ₂ gas generation step, (b) show the O ₂ gas releasing step. It is explanatory drawing which showed the fuel reforming apparatus of Embodiment 3 typically. It is explanatory drawing for demonstrating the implementation method of the activity test in Experimental example 1. FIG. ₃ is an XRD pattern of an oxide mixture composed of Ce _0.5 Zr _0.5 O ₂ , Co ₃ O ₄ , V ₂ O ₅ and MnO ₂ in Experimental Example 1. In Experimental Example _1, XRD pattern in the initial state of _{Ce 0.62 Cr 0.33 Pd 0.05 O 2} , Rietveld analysis pattern, and the difference spectrum. 4 is an XRD pattern, Rietveld analysis pattern, and difference spectrum after application of an electric field of Ce _0.62 Cr _0.33 Pd _0.05 O ₂ in Experimental Example 1. 4 is an XRD pattern, Rietveld analysis pattern, and difference spectrum after hydrogen reduction of Ce _0.62 Cr _0.33 Pd _0.05 O ₂ in Experimental Example 1. 4 is an XRD pattern, Rietveld analysis pattern, and difference spectrum after supplying water vapor after reduction of Ce _0.62 Cr _0.33 Pd _0.05 O ₂ in Experimental Example 1. In Experiment 2, Ce _0.67 Cr _0.33 O ₂ , Ce _0.66 Cr _0.33 A _0.01 O ₂ (however, A: from the group consisting of Pd, Pt, Rh, Au, and Ag) It is a result of an activity test when using 1 type selected. The result of the activity test when using Ce _(0.67-x) Cr _0.33 Pd _x O ₂ (x = 0, 0.01, 0.03, 0.05) in Experimental Example 3 is there. It is an absorption spectrum of the energy absorption edge in the K shell of Ce in Ce _0.62 Cr _0.33 Pd _0.05 O ₂ obtained by In-situ XAFS measurement in Experimental Example 4. In Experimental Example 5, a diagram showing the relationship between the Raman peak shift amount and O ₂ release rate of each oxide. In Experimental Example 5, the relationship between the Raman peak shift amount of Ce _(0.67−x) Cr _0.33 Pd _x O ₂ (x = 0.01, 0.03, 0.05) and the O ₂ release rate is shown. FIG. 7 is an XRD pattern, a Rietveld analysis pattern, and a difference spectrum in the initial state of Ce _0.67 Cr _0.33 O ₂ in Experimental Example 6. 7 shows an XRD pattern, a Rietveld analysis pattern, and a difference spectrum in the initial state of Ce _0.5 Cr _0.5 O ₂ in Experimental Example 6. 7 shows an XRD pattern, a Rietveld analysis pattern, and a difference spectrum in an initial state of Ce _0.3 Cr _0.7 O ₂ in Experimental Example 6. 7 _shows an XRD pattern, a Rietveld analysis pattern, and a difference spectrum in an initial state of Ce _0.66 Cr _0.33 Pd _0.01 O ₂ in Experimental Example 6. 7 _shows an XRD pattern, a Rietveld analysis pattern, and a difference spectrum in an initial state of Ce _0.64 Cr _0.33 Pd _0.03 O ₂ in Experimental Example 6. 7 _shows an XRD pattern, a Rietveld analysis pattern, and a difference spectrum in an initial state of Ce _0.62 Cr _0.33 Pd _0.05 O ₂ in Experimental Example 6.

(Embodiment 1)
The catalyst body of Embodiment 1 is demonstrated using FIG. As illustrated in Figure 1, the catalyst body 1 of the present _{embodiment, Ln (1-y-x} ) M y A x O z ( where, Ln: rare earth element, M: transition metal element, A: noble metal element And at least one transition metal element different from M, having an oxide 11 represented by 0.03 ≦ x ≦ 0.1, 0.1 ≦ y <0.5, 2 ≦ z ≦ 4) ing. This will be described in detail below. FIG. 1 shows an example in which the catalyst body 1 is composed of the oxide 11.

  In the above chemical formula (composition formula), Ln is a rare earth element. Specific examples of Ln include Ce (cerium), La (lanthanum), Pr (praseodymium), Nd (neodymium), Sm (samarium), Eu (eurobium), and the like. These can be used alone or in combination of two or more. Ln is preferable to contain Ce, more preferably Ce, from the viewpoint of easily causing a valence change.

  In the above chemical formula, M is a transition metal element. Specifically, M is at least one selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements, Group 7 elements, Group 8 elements, Group 9 elements, Group 10 elements, and Group 11 elements. Can be included. According to this configuration, there are advantages such that it is easy to relax lattice distortion caused by a change in the valence of the rare earth element Ln such as Ce, reduce the regularity of oxygen defects, and easily increase the doping amount of the A element. is there. Group 4 transition metal elements include Ti (titanium), Zr (zirconium), Group 5 transition metal elements include V (vanadium), Nb (niobium), Group 6 transition metal elements include Cr (chromium). ), Mo (molybdenum), W (tungsten), Mn (manganese) as the group 7 transition metal element, Fe (iron) as the group 8 transition metal element, Co as the group 9 transition metal element (Cobalt) Ni (nickel) is preferable as the group 10 transition metal element, and Cu (copper) is preferable as the group 11 transition metal element. M preferably contains Cr, more preferably Cr, from the viewpoint of a large range of valence change.

In the above chemical formula, A is at least one of a noble metal element and a transition metal element different from M. That is, A is at least one of a noble metal element and a transition metal element not used as a constituent element in M. Specific examples of the noble metal element include Pt (platinum), Pd (palladium), Rh (rhodium), Ir (iridium), Ru (ruthenium), Os (osmium), and the like. These can be used alone or in combination of two or more. Specific examples of the transition metal element include Cu (copper), Ni, and Co. These can be used alone or in combination of two or more. A is preferably at least one selected from the group consisting of Pt, Pd, Rh, Au, and Cu from the viewpoints of improving O ₂ releasing activity, activity of decomposing fuel such as water, and increasing lattice distortion. It may contain a seed element, more preferably at least one element selected from the group consisting of Pt, Pd, Rh, and Cu, and even more preferably Pt, Pd. , And at least one element selected from the group consisting of Cu, and even more preferably Pd.

In the above chemical formula, x is 0.03 or more and 0.1 or less. When x exceeds 0.1, the amount of Ln that is the center of valence change decreases, and the oxide itself becomes difficult to change in valence. Moreover, excess A element tends to precipitate out of the crystal. x is preferably 0.09 or less, more preferably 0.08 or less, and even more preferably 0.07 or less. Further, x is preferably 0.04 or more from the viewpoint of increasing the lattice distortion by increasing the amount of A and promoting the change in the valence of Ln, improving the H ₂ generation activity, improving the O ₂ releasing activity, etc. More preferably, it is 0.05 or more.

  In the above chemical formula, y is 0.1 or more and less than 0.5. When y is 0.5 or more, it becomes difficult for M to dissolve in Ln and the crystal structure is likely to change. y is preferably 0.48 or less, more preferably 0.45 or less, even more preferably 0.43 or less, even more preferably 0.4 or less, even more preferably 0.38 or less, Most preferably, it is 0.36 or less. On the other hand, when y is less than 0.1, it becomes impossible to relieve the lattice distortion caused by the valence change of the rare earth element Ln such as Ce. y is preferably 0.15 or more, more preferably 0.2 or more, still more preferably 0.25 or more, and even more preferably 0.3 or more.

  In the above chemical formula, z is 2 or more and 4 or less. If z exceeds 4, the M element (Cr or the like) or the A element (Pd or the like) constituting the oxide 11 needs to be an expensive number of ions, which may impair the stability of the oxide 11. is there. z is preferably 3.5 or less, more preferably 3 or less, and even more preferably 2.5 or less. When z is less than 2, the M element (Cr or the like) or the A element (Pd or the like) constituting the oxide 11 is metalized and easily deposited. z is preferably 2; In this case, the crystal structure of the oxide 11 is a fluorite-type crystal structure having a larger unit cell free space and lower ionic bondability than the perovskite structure. Therefore, the mobility of the constituent elements and oxygen ions constituting the oxide 11 is increased, and the valence change of the constituent elements is easily promoted.

  When A is composed of a plurality of noble metal elements / transition metal elements, the composition ratio of x is shared by the plurality of noble metal elements / transition metal elements. When M is composed of a plurality of transition metal elements, the composition ratio of y is shared by the plurality of transition metal elements. Similarly, when Ln is composed of a plurality of rare earth elements, the composition ratio of (1-yx) is shared by the plurality of rare earth elements.

Specifically, the oxide 11 has the chemical formula Ce _(1- yx ₎ Cr _y Pd _x O ₂ (where 0.03 ≦ x ≦ 0.05, 0.1 ≦ y <0.5). It can be composed of a certain oxide. According to this arrangement, generation of H ₂ gas, O ₂ can prompt the generation of gas, the catalyst stability can be improved catalytic body can be made reliable. More specifically, the oxide 11 is an oxide having a chemical formula of Ce _(0.67-x) Cr _0.33 Pd _x O ₂ (where 0.03 ≦ x ≦ 0.05). Can do. According to this structure, the said effect can be made more reliable.

The oxide 11 can be configured to have oxygen ion conductivity and electronic conductivity. When the oxide 11 has oxygen ion conductivity, the oxide 11 is easily captured by the oxide 11 when the fuel containing oxygen atoms, the hydrogen atom, and the fuel containing oxygen atoms are decomposed. In addition, when an electric field is applied to the catalyst body 1, the oxide 11 easily develops an oxygen pumping action by the electric field, and it is easy to promote the trapping of oxygen into the oxide 11 and the release of O ₂ from the oxide 11. . In addition, since the oxide 11 has electronic conductivity, it is easy to promote the decomposition reaction of the fuel accompanying the transfer of electrons. Therefore, according to this structure, the catalyst body 1 capable of decomposing the fuel at a lower temperature is obtained.

Specifically, the oxygen ion conductivity of the oxide 11 can be 1 × 10 ⁻⁵ or more and 1 × 10 ⁻² S / cm or less. According to this structure, the effect when the oxide 11 has oxygen ion conductivity can be ensured. In addition, the electron conductivity of the oxide 11 can be specifically set to 1 × 10 ⁻² or more and 1 × 10 ⁻¹ S / cm or less. According to this structure, the effect when the oxide 11 has electronic conductivity can be ensured.

The specific surface area of the oxide 11 can be 5 or more and 100 m ² / g or less. According to this configuration, it becomes easy to obtain the catalyst body 1 having an excellent balance between H ₂ generation activity and O ₂ release activity. The specific surface area of the oxide 11 is preferably 8 m ² / g or more, more preferably 10 m ² / g or more, still more preferably 25 m ² / g or more, and further from the viewpoint of improving H ₂ generation activity. Preferably, it can be 50 m ² / g or more. The specific surface area of the oxide 11 is preferably 90 m ² / g or less, more preferably 80 m ² / g or less, and still more preferably 70 m ² from the viewpoint of facilitating securing of the O ₂ releasing activity. / G or less. The specific surface area is a value (adsorption gas: nitrogen) measured in accordance with JIS R1626-1996 “Method for measuring specific surface area of fine ceramic powder by gas adsorption BET method”. The measurement is performed using a sample before being subjected to fuel reforming.

The catalyst body 1 can be used to promote generation of H ₂ gas by decomposition of fuel containing hydrogen atoms. According to this configuration, it is possible to take out the H ₂ gas by reforming the fuel containing hydrogen atoms. Further, the catalyst body 1 can be used for promoting the release of O ₂ gas using oxygen captured during decomposition of the fuel containing oxygen atoms. According to this configuration, the O ₂ gas can be taken out by reforming the fuel containing oxygen atoms. Further, the catalyst body 1 can be used to promote both generation of H ₂ gas by decomposition of a fuel containing hydrogen atoms and oxygen atoms and release of O ₂ gas using oxygen captured during decomposition of the fuel. . According to this configuration, it is possible to take out both H ₂ gas and O ₂ gas by reforming the fuel containing hydrogen atoms and oxygen atoms.

  Examples of the fuel containing hydrogen atoms include hydrocarbons and ammonia. Examples of the fuel containing oxygen atoms include oxides, ozone, nitrides, sulfides, and the like. Examples of the fuel containing hydrogen atoms and oxygen atoms include water, alcohols, urea, hydrogen peroxide, and the like.

The catalyst body 1 of the present embodiment has an oxide 11. In the oxide 11, the valence balance is destabilized and lattice distortion is likely to occur, and the valence of components constituting the oxide 11 is likely to change. Therefore, the oxide 11 itself can fluctuate in valence, and can selectively perform two reactions of oxidation and reduction. Therefore, for example, when a fuel containing hydrogen atoms such as water and oxygen atoms is brought into contact with the catalyst body 1 and an electric field is applied, polarization in the oxide 11 is induced, and the H ₂ gas is decomposed by the decomposition of the fuel. An oxidation reaction such as generation and oxygen trapping and a reduction reaction such as release of O ₂ gas using the trapped oxygen can be selectively performed. In addition, even when the oxide 11 is exposed to a hydrogen environment or is applied with an electric field, the formation of a different phase between different elements hardly occurs and the crystal structure hardly changes. Therefore, the catalyst body 1 has high catalyst stability compared with the conventional catalyst body. Therefore, according to the catalyst body 1, the generation of H ₂ gas, it is possible to promote the formation of O ₂ gas, it is possible to improve the catalytic stability.

  In addition, the oxide 11 can be produced using, for example, a complex polymerization method. When the complex polymerization method is used, for example, the salt of each constituent element as a precursor (inorganic salt such as nitrate), citric acid, ethylene glycol, pure so as to have the same constituent element ratio as the target oxide Mix water well at about 75-80 ° C. The obtained mixture was dried at about 100 ° C. for about 12 to 48 hours, calcined at about 400 to 450 ° C. for about 2 to 48 hours to decompose and remove citric acid and ethylene glycol in advance, and then obtained. The target oxide 11 can be obtained by subjecting the calcined material to main firing at about 500 to 900 ° C. for about 5 to 48 hours.

(Embodiment 2)
The catalyst body of Embodiment 2 is demonstrated using FIG. Of the reference numerals used in the second and subsequent embodiments, the same reference numerals as those used in the above-described embodiments represent the same components as those in the above-described embodiments unless otherwise indicated.

As illustrated in FIG. 2, the catalyst body 1 of the present embodiment includes the oxide 11 described above in Embodiment 1, and the noble metal element 12 supported on the surface of the oxide 11. In the first embodiment, as shown in FIG. 1, the example in which the catalyst body 1 is made of the oxide 11 is shown. However, according to the configuration of the present embodiment, the contact is made by both the oxide 11 and the noble metal element 12. It becomes easy to promote the decomposition reaction of the fuel brought into contact with the medium 1. Therefore, according to the above construction, generation of H ₂ gas, O ₂ catalyst 1 release capable of urging the gas can be obtained at a lower temperature.

Specifically, the noble metal element 12 supported on the surface of the oxide 11 can include at least one selected from the group consisting of Pt, Pd, Rh, and Ru. According to this configuration, H ₂ generation activity and O ₂ release activity can be enhanced. The noble metal element 12 supported on the surface of the oxide 11 is preferably Pt, Pd, or the like, more preferably Pd, from the viewpoint of the balance of H ₂ generation activity and O ₂ release activity. Good.

  Note that the metal element can be supported on the oxide 11 by, for example, an impregnation method. In the case of using the impregnation method, for example, a salt of a noble metal element (acetate or the like) that is a precursor of the noble metal element to be supported and pure water are put into an evaporator, and water is evaporated to dryness. At this time, the amount of the salt of the noble metal element is adjusted so that the noble metal element becomes a predetermined mass% with respect to the oxide 11. Thereafter, the dried solid is baked at about 400 to 600 ° C. for about 2 to 48 hours, whereby the noble metal element can be supported on the oxide 11 at a predetermined mass%.

  The total amount of the noble metal element 12 supported on the oxide 11 can be 0.3 mass% or more and 7 mass% or less.

The loading is preferably 0.5% by mass or more, more preferably 0.7% by mass or more, and further preferably 1% by mass from the viewpoint of ensuring the effect of promoting the decomposition reaction of the fuel. % Or more. On the other hand, the supported amount is preferably 7% by mass or less, more preferably 6% by mass or less, and still more preferably 5% by mass or less from the viewpoint of suppressing inhibition of O ₂ release.

An example of a fuel reforming method using the catalyst body 1 of the present embodiment will be described with reference to FIG. Specifically, the fuel reforming method includes an H ₂ generation step and an O ₂ release step. As shown in FIG. 3A, in the H ₂ generation step, fuel (in this embodiment, water (H ₂ O) is exemplified as fuel) is brought into contact with the heated catalyst body 1 to heat the fuel. In this process, H ₂ is generated by decomposition and the catalyst body 1 captures oxygen. On the other hand, as shown in FIG. 3B, the O ₂ releasing step is a step in which the catalyst body 1 that has captured oxygen is heated to release O ₂ . External energy can be applied to the catalyst body 1 in the O ₂ releasing step, or the H ₂ generating step and the O ₂ releasing step. Examples of the external energy include an electric field, a magnetic field, and plasma. Of these, an electric field is preferred as the external energy. This is because application of an electric field to the catalyst body 1 easily induces polarization of the catalyst body 1, changes in the valence of constituent elements, and lattice distortion, and facilitates the fuel decomposition reaction. In addition, the electric current value at the time of applying an electric field can be 5 mA or more and 15 mA or less, for example, and the voltage value at the time of applying an electric field can be 0.2 kV or more and 1.7 kV or less, for example.

  Other configurations and operational effects are the same as those of the first embodiment.

(Embodiment 3)
A fuel reformer according to Embodiment 3 will be described with reference to FIG. As illustrated in FIG. 4, the fuel reformer 2 of this embodiment includes a reactor 21, a catalyst body 1, a heat source 22, an electric field application unit 23, and a control unit 24.

The reactor 21 is a container for causing thermal decomposition of a fuel containing at least one of hydrogen atoms and oxygen atoms using the catalytic action of the catalyst body 1. In the present embodiment, specifically, the reactor 21 accommodates the catalyst body 1 and an introduction part 211 for introducing water as a fuel containing both hydrogen atoms and oxygen atoms into the reactor 21. The housing unit 212 and a deriving unit 213 for deriving the generated H ₂ gas or O ₂ gas to the outside of the reactor 21 are provided. The introduction unit 21 can be connected to a water supply path (not shown) having an on-off valve.

  Specifically, the catalyst body 1 of Embodiment 1 or Embodiment 2 is used as the catalyst body 1.

  The heat source 22 is for heating the catalyst body 1 as necessary. As the heat source 22, for example, a heat exchanger or a heater can be used. In the present embodiment, the heat source 22 is composed of a heat exchanger. The heat exchanger is configured such that the catalyst body 1 can be heated using heat energy such as exhaust heat from a boiler or solar heat, for example. In this embodiment, water (water vapor) vaporized by the heat exchanger is configured to be supplied to the catalyst body 1.

  The electric field applying unit 23 is for applying an electric field to the catalyst body 1. In the present embodiment, the electric field application unit 23 specifically includes a pair of electrodes 230 and a power source 233. The pair of electrodes 230 includes a first electrode 231 and a second electrode 232, and is disposed with the catalyst body 1 interposed therebetween. The first electrode 231 and the second electrode 232 are electrically connected to the power source 233. The first electrode 231 and the second electrode 232 are configured to allow gas permeation.

  The control unit 24 switches between the supply of the fuel containing at least one of hydrogen atoms and oxygen atoms into the reactor 21 and the supply stop of the fuel, and the electric field applied to the catalyst body 1 by the electric field applying unit 23. Control. In the present embodiment, specifically, the control unit 24 is configured by an electronic control device including a known microcomputer or the like. The control unit 24 is configured to variably control the current applied to the catalyst body 1 by the electric field application unit 23. In addition, the control unit 24 performs first current control for applying a first current to the catalyst body 1 and second current control for applying a second current having a current value higher than the first current to the catalyst body 1. It is configured as follows.

The fuel reformer 2 can be operated as follows, for example. First, the catalyst body 1 is heated by the heat source 22. Next, fuel is supplied into the reactor 21, and the fuel is brought into contact with the catalyst body 1. In the present embodiment, the fuel supply / supply stop switching is performed by controlling the opening degree of the on-off valve provided in the fuel supply path by the control unit 24. Next, an electric field for generating H ₂ gas is applied to the catalyst body 1 by the electric field applying unit 23. In the present embodiment, an electric field is applied to the catalyst body 1 by applying a voltage between the pair of electrodes 230 and causing a first current to flow through the catalyst body 1. Thus, H ₂ gas is generated from the fuel by the catalytic action of the catalyst body 1, and oxygen due to the decomposition of the fuel is captured by the catalyst body 1. The H ₂ gas can be generated without applying an electric field, but more H ₂ gas can be generated when an electric field is applied. Then, after a predetermined reaction time (for example, several minutes to several tens of minutes) has elapsed, the supply of fuel to the catalyst body 1 is stopped. Subsequently, the catalyst body 1 is heated with the heat source 22 as needed. Incidentally, if I have a temperature suitable for O ₂ release is obtained by the heating at the time of H ₂ generation may not heat the catalyst body 1 again. Next, the electric field applying unit 23 applies an electric field for releasing O ₂ gas to the catalyst body 1. In the present embodiment, an electric field is applied to the catalyst body 1 by applying a voltage between the pair of electrodes 230 and causing the second current to flow through the catalyst body 1. Thereby, O ₂ gas is generated from the oxygen trapped in the catalyst body 1. Although an example of the operation in which the electric field applying unit 23 is functioned has been described above, the fuel reformer 2 can be operated without functioning the electric field applying unit 23 (ON / OFF control).

The fuel reformer 2 of the present embodiment has a catalyst body 1 that can promote generation of H ₂ gas and generation of O ₂ gas and has high catalyst stability. Therefore, according to the fuel reforming apparatus 2 of the present embodiment, H ₂ gas and O ₂ gas can be generated by repeatedly using the catalyst body 1.

(Experimental example 1)
<Production of catalyst body>
Ce _0.62 Cr _0.33 Pd _0.05 O ₂ was produced according to the complex polymerization method described above. At this time, Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours. Specifically, in the complex polymerization method, citric acid monohydrate and ethylene glycol were weighed so that the amount of the material used was three times the amount of the metal used. Each sample was placed in a polytetrafluoroethylene beaker, and distilled water was added and stirred while heating to about 70 ° C. When the water had evaporated to some extent, it was evaporated to dryness on a hot stirrer. Then, main baking was performed using the flow-type baking furnace.

In this way, a catalyst body made of Ce _0.62 Cr _0.33 Pd _0.05 O ₂ (hereinafter sometimes simply referred to as “Ce _0.62 Cr _0.33 Pd _0.05 O ₂ ”) was produced. . The obtained catalyst body was put in a disk having a diameter of 20 mm with about 2 g of the catalyst body, pressed with a press molding machine at a pressure of 60 kN for 10 minutes to be pelletized, and then pulverized. By sieving, the particle size was adjusted to 355 to 500 μm.

For comparison, a catalyst body in which Pd is supported on an oxide mixture of Ce _0.5 Zr _0.5 O ₂ , Co ₃ O ₄ , V ₂ O ₅ and MnO ₂ (hereinafter referred to as Pd / (CZO + Co ₃ O ₄ + V ₂ O ₅ + MnO ₂ )).

<Activity test>
An activity test was conducted using each catalyst body. The activity test uses a fixed bed flow reactor, the amount of the catalyst body is 1 g, the temperature rising temperature is 10 K / min, the reaction temperature is 623 K, and the total gas flow rate is 200 SCCM (internal standard: Ar 10 SCCM, balance: He). did. In the activity test, first, as shown in FIG. 5, a prepared predetermined catalytic body 53 is filled in a reaction tube 54 made of a quartz tube having an outer diameter of 18 mm and an inner diameter of 15 mm, and further inside the reaction tube 54. Mesh electrodes 55 and 56 (manufactured by SUS) capable of gas permeation were disposed at both ends of the catalyst body 53 in the axial direction. The mesh electrodes 55 and 56 were contacted with rod electrodes for voltage application, respectively. The reaction tube 54 containing the catalyst body 53 and the electrodes 55 and 56 was set in the apparatus 50. The water in the container 51 was fed into the reaction tube 54 by the pump 52 and supplied to the catalyst body 53 in a vaporized state. A power source (not shown) is connected to the electrodes 55 and 56 so that an electric field can be applied to the catalyst body 53. The gas released from the downstream of the catalyst body 53 was collected in the sample bottle 57.

In the hydrogen generation activity test, the catalyst body 53 heated to the reaction temperature was pre-reduced for 30 minutes with Ar—He gas (Ar 5% internal standard) containing 10% by volume of H ₂ . Next, a current of 5 mA was applied to the catalyst body 53 for 10 minutes in an Ar—He gas (Ar 5% internal standard) atmosphere containing 40% by volume of H ₂ O (water vapor), and the amount of H ₂ produced was measured. On the other hand, in the oxygen release activity test, the catalyst body 53 heated to the above reaction temperature was pre-oxidized with Ar—He gas (Ar 5% internal standard) containing 10% by volume of O ₂ for 30 minutes. Next, after flowing Ar—He gas for 5 minutes, a current of 15 mA was applied to the catalyst body 53 for 5 minutes in an Ar—He gas atmosphere, and the amount of O ₂ released was measured.

  Moreover, the analysis of the product by the catalytic reaction was performed using a quadrupole mass spectrometer (measurement temperature range: room temperature to 1073 K), and the current value and voltage value in each operation were recorded using an oscilloscope.

As a result, the catalyst body composed of Pd / (CZO + Co ₃ O ₄ + V ₂ O ₅ + MnO ₂ ) has a maximum H ₂ production rate of 0.22 mmol / min and a maximum O ₂ release rate of 0.13 mmol / min. there were. On the other hand, the catalyst body made of Ce _0.62 Cr _0.33 Pd _0.05 O ₂ had a maximum H ₂ production rate of 0.27 mmol / min and a maximum O ₂ release rate of 0.14 mmol / min. . From this result, the catalyst body made of Ce _0.62 Cr _0.33 Pd _0.05 O ₂ is similar to the catalyst body made of Pd / (CZO + Co ₃ O ₄ + V ₂ O ₅ + MnO ₂ ). It can be said that it is possible to promote both generation of H ₂ by thermal decomposition of O ₂ and release of O ₂ using oxygen captured during thermal decomposition of water.

<Crystal structure analysis of catalyst body>
In order to analyze the change in the crystal structure of the catalyst body in the initial state after the above activity test, XRD measurement was performed. A Smart Lab manufactured by Rigaku was used as the XRD measurement apparatus. At this time, the XRD measurement conditions were a start angle: 10 °, an exit angle: 90 °, a scan step: 0.01 °, and a scan speed: 20 ° / min.

FIG. 6 shows an XRD pattern of an oxide mixture composed of Ce _0.5 Zr _0.5 O ₂ , Co ₃ O ₄ , V ₂ O ₅ and MnO ₂ . FIG. 6 also shows the results for the oxide mixture heat-treated at 1073K. According to this result, it can be seen that the detected peak of the oxide mixture is different between the initial state and the state after the release of O ₂ . Specifically, in the above oxide mixture, after releasing O ₂ , some of the peaks of CZO, Co ₃ O ₄ , and V ₂ O ₅ disappeared, and a new peak of CeVO ₄ appeared. From this result, it can be seen that in the above oxide mixture, Ce and V are combined to release O ₂ . In other words, it can be said that the above oxide mixture is difficult to use repeatedly because the heterogeneous elements are complexed and a heterogeneous phase is precipitated, resulting in poor catalyst stability.

In the above oxide mixture, disappearance was also observed in peaks other than Ce and V. This is presumably because a part of the film was made amorphous by the change in crystal structure due to O ₂ emission. Further, in the above oxide mixture, a peak similar to the XRD pattern after the activity test was detected when the temperature was increased to 1073K, but the XRD pattern when the temperature was increased to 1073K disappeared. There were many peaks. From this result, the oxide mixture was partially decomposed or compounded by being exposed to high temperature, so that crystallization did not proceed well, and as a result, a peak was observed in the XRD pattern. It is presumed that there was not.

On the other hand, for Ce _0.62 Cr _0.33 Pd _0.05 O ₂ , FIG. 7 shows the XRD pattern, Rietveld analysis pattern, and difference spectrum in the initial state, and FIG. 8 shows the XRD pattern after applying the electric field, Belt analysis pattern and difference spectrum, FIG. 9 XRD pattern after hydrogen reduction, Rietveld analysis pattern, and difference spectrum, FIG. 10 XRD pattern after supplying water after hydrogen reduction, Rietveld analysis pattern And shows the difference spectrum. 7 to 10, Rwp is a weighted pattern reliability factor, Re is a statistical error between actual measurement and calculation, Rp is an R factor without weighting, and S is an Rwp value considering the statistical error. 7 to 10 show the measured XRD pattern, Rietveld analysis pattern, and the difference spectrum between the measured XRD pattern and the Rietveld analysis pattern. According to these results, Ce _0.62 Cr _0.33 Pd _0.05 O ₂ is between the initial state and the activity test (after hydrogen reduction, after electric field application, after hydrogen reduction and after water vapor supply). There was no significant change in the crystal structure as seen with the oxide mixture. From this result, it was confirmed that Ce _0.62 Cr _0.33 Pd _0.05 O ₂ has high catalyst stability and can generate H ₂ gas and O ₂ gas by repeated use.

(Experimental example 2)
<Production of catalyst body>
In the same manner as in Experimental Example 1, the following oxides were produced according to the complex polymerization method described above.
・ Ce _0.67 Cr _0.33 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O and Cr (NO ₃ ) ₃ .6H ₂ O were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.66 Cr _0.33 Pd _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
・ Ce _0.66 Cr _0.33 Pt _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pt (NH ₄ ) ₄ (NO ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.66 Cr _0.33 Rh _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Rh (NO ₃ ) ₃ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.66 Cr _0.33 Au _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and HAuCl ₄ .4H ₂ O were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
・ Ce _0.66 Cr _0.33 Ag _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and AgNO ₃ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.

As described above, Ce _0.67 Cr _0.33 O ₂ , Ce _0.66 Cr _0.33 A _0.01 O ₂ (however, A: Pd, Pt, Rh, Au, and Ag are selected. 1 type). The obtained catalyst bodies were sized in the same manner as in Experimental Example 1.

Next, an activity test was performed in the same manner as in Experimental Example 1 using each catalyst body. The result is shown in FIG. As shown in FIG. 11, it can be seen that when Pd is used as the A element constituting the oxide, the H ₂ generation activity and the O ₂ release activity are the highest.

(Experimental example 3)
<Production of catalyst body>
In the same manner as in Experimental Example 1, the following oxides were produced according to the complex polymerization method described above.
・ Ce _0.67 Cr _0.33 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O and Cr (NO ₃ ) ₃ .6H ₂ O were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.66 Cr _0.33 Pd _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.64 Cr _0.33 Pd _0.03 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.62 Cr _0.33 Pd _0.05 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.

From the above, Ce _0.67 Cr _0.33 O ₂ , Ce _(0.67-x) Cr _0.33 Pd _x O ₂ (where x = 0, 0.01, 0.03, 0.05) Produced. The obtained catalyst bodies were sized in the same manner as in Experimental Example 1.

Next, an activity test was performed in the same manner as in Experimental Example 1 using each catalyst body. The result is shown in FIG. As shown in FIG. 12, it can be seen that the H ₂ generation activity and the O ₂ release activity are the highest when the Pd doping amount is 5% (x = 0.05 in the oxide).

(Experimental example 4)
<Production of catalyst body>
In the same manner as in Experimental Example 1, the following oxides were produced according to the complex polymerization method described above. The obtained oxide was sized in the same manner as in Experimental Example 1.
Ce _0.62 Cr _0.33 Pd _0.05 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.

60 mg of the above oxide was pressed at 60 kN for 30 seconds to produce a 10 mm disk-shaped measurement sample. The measurement sample was heated from room temperature to 623 K and held for 10 minutes. Next, He (100 SCCM) was used as the inert gas, and an electric field (applied current: 15 mA) was applied to the measurement sample in the inert gas for 10 minutes. Next, water vapor (He: H ₂ O = 100 SCCM: 20 SCCM) was passed through the measurement sample for 10 minutes.

  Next, in order to confirm the change in the valence of Ce in the oxide, the initial measurement sample, the measurement sample after applying the electric field in the inert gas, and the measurement sample after circulating the water vapor were measured using the In-situ X The absorption spectrum of the energy absorption edge (Ce-K edge) in the K shell of Ce was determined by linear absorption fine structure (XAFS) measurement. For the XAFS measurement, the B14B2 beam line of the large synchrotron radiation facility SPring-8 was used. The measurement range was 5700-5900 eV. As analysis software, free software Athena was used.

  The result is shown in FIG. When the valence change of Ce from the Ce edge jump position was analyzed, as shown in FIG. 13, by applying a voltage to the initial measurement sample, the edge jump was shifted to the reduction side, and then the water vapor was removed. It was confirmed that the edge jump was shifted to the oxidation side by supplying. From this result, it is understood that the valence change of Ce occurs in the oxide of the measurement sample. Therefore, it can be said that the oxide itself can fluctuate in valence and can selectively carry out two reactions of oxidation and reduction.

(Experimental example 5)
<Production of catalyst body>
In the same manner as in Experimental Example 1, the following oxides were produced according to the complex polymerization method described above. In addition, each obtained oxide was sized similarly to Experimental Example 1.
Ce _0.66 Cr _0.33 Pd _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.64 Cr _0.33 Pd _0.03 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.62 Cr _0.33 Pd _0.05 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
・ Ce _0.66 Cr _0.33 Pt _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pt (NH ₄ ) ₄ (NO ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.66 Cr _0.33 Rh _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Rh (NO ₃ ) ₃ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.66 Cr _0.33 Au _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and HAuCl ₄ .4H ₂ O were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
・ Ce _0.66 Cr _0.33 Ag _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and AgNO ₃ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.66 Cr _0.33 Cu _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Cu (NO ₃ ) ₃ .3H ₂ O were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.

Next, using each oxide, an activity test was performed in the same manner as in Experimental Example 1, and the O ₂ release rate was measured. For each of the initial oxides, the Raman peak shift amount was measured as lattice distortion by Raman spectroscopic analysis. The Raman spectroscopic analyzer includes a Jasco Corp. “Laser Raman spectrometer NRS-4500” manufactured by the same company was used. The measurement conditions were a light source having a wavelength of 532 nm and a resolution of 0.7 cm ⁻¹ .

The results are shown in FIG. 14 and FIG. According to FIG. 14, in the CeCrAO ₂ (A: Pt, Pd, Rh, Au, Ag, or Cu) -based oxide, the O ₂ release rate is almost proportional to the lattice strain due to the doping of the A element. I understand that. Further, it was confirmed that among the noble metal elements constituting the A element, it is easy to increase the lattice strain when Pd is used. In FIG. 14, for example, the O ₂ release rate is greatly different between the case where the element A is Pt and the case where it is Cu because of the influence of metal properties such as electron donation and attractive properties. I can think of it.

FIG. 15 also shows that the O ₂ release rate increases as the doping amount of Pd increases. From this result, in the CeCrAO ₂ (A: Pt, Pd, Rh, Au, Ag, or Cu) -based oxide, the lattice distortion increases by increasing the doping amount of the A element, and the O field is applied by applying the electric field. It turns out that it becomes easy to discharge | release ₂ .

(Experimental example 6)
<Production of catalyst body>
In the same manner as in Experimental Example 1, the following oxides were produced according to the complex polymerization method described above. In addition, each obtained oxide was sized similarly to Experimental Example 1.
・ Ce _0.67 Cr _0.33 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O and Cr (NO ₃ ) ₃ .6H ₂ O were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
・ Ce _0.5 Cr _0.5 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O and Cr (NO ₃ ) ₃ .6H ₂ O were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
・ Ce _0.3 Cr _0.7 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O and Cr (NO ₃ ) ₃ .6H ₂ O were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.66 Cr _0.33 Pd _0.01 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.64 Cr _0.33 Pd _0.03 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
Ce _0.62 Cr _0.33 Pd _0.05 O ₂
Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. The main baking temperature was 500 ° C., and the main baking time was 5 hours.
1 mass% Pd / Ce _0.66 Cr _0.33 Pd _0.01 O ₂
Metal loading on the Ce _0.66 Cr _0.33 Pd _0.01 O ₂ oxide support was performed by an impregnation method. The carrier and the metal precursor to be supported were weighed, and about 30 mL of distilled water or acetone was added and mixed at 120 rpm for 2 hours. Ce (NO ₃ ) ₃ .6H ₂ O, Cr (NO ₃ ) ₃ .6H ₂ O, and Pd (OCOCH ₃ ) ₂ were used as the salt of each constituent element as a precursor. Thereafter, evaporation to dryness was performed. The evaporated product was dried at 120 ° C. overnight and then calcined at 500 ° C. for 5 hours.

<Crystal structure analysis of catalyst body>
About each oxide, it carried out similarly to Experimental example 1, and implemented the XRD measurement in an initial state. The results are shown in FIGS. 16 to 18, it can be seen that when the Cr doping amount is 50% or more (y = 0.5 in the oxide), Cr becomes difficult to dissolve in Ce and another crystal structure appears. Further, according to FIG. 16 and FIGS. 19 to 21, no change in the crystal structure was observed until the Pd doping amount was 5% (x = 0.05 in the oxide).

<Activity test>
Using each oxide and 1 mass% Pd / Ce _0.66 Cr _0.33 Pd _0.01 O _{2 in} which 1% by mass of Pd was separately supported on the oxide surface layer, an activity test was conducted in the same manner as in Experimental Example 1. Went. The results are summarized in Table 1.

No. in Table 1 1-No. By comparing the results of the catalyst bodies of No. 3, the catalytic activity when the ratio of Ce / Cr amount (composition ratio) is changed can be analyzed. Specifically, it can be seen that the H ₂ generation activity increases as the Cr content increases. This is presumably because the absolute amount of valence fluctuation in the whole oxide increased due to the increase in Cr with a wide valence change. On the other hand, it can be seen that the O ₂ releasing activity decreases as the Cr content increases. Further, Ce _0.5 Cr _0.5 O ₂ and Ce _0.3 Cr _0.7 O ₂ in which the combination of Ce and Cr was insufficient were low in O ₂ releasing activity. From this result, it can be said that the O ₂ releasing activity can be improved by sufficiently combining Ce and Cr as the M element.

Next, no. 1, no. 4-No. By comparing the results of the catalyst bodies of No. 6, it is possible to analyze the O ₂ releasing activity when the Pd doping amount is changed. Specifically, when the Pd doping amount was 5%, the O ₂ emission amount became maximum. This is presumably because the lattice distortion in the oxide increases due to the increase in the Pd doping amount, and the O ₂ emission amount increases. In Table 1, No. 4, no. According to the result of the catalyst body of No. 7, there was a tendency that the amount of released O ₂ decreased by supporting Pd. This is presumably because Pd covering the surface of the oxide hindered oxygen in the lattice from coming out as O ₂ .

Next, no. 1, no. 4-No. By comparing the results of the catalyst bodies of No. 6, it is possible to analyze the H ₂ generation activity when the Pd doping amount is changed. Specifically, as the amount of doped Pd increased, the amount of H ₂ produced and the amount of O ₂ released increased. According to this result, it can be said that Pd in the oxide is effective in cutting the OH bond of water as a fuel and may be an active point for H ₂ generation and O ₂ release. Therefore, it is presumed that as the amount of doped Pd increases, the active sites for H ₂ generation and O ₂ release increase and the H ₂ generation activity and O ₂ release activity improve. Further, it is confirmed that the amount of O ₂ released is approximately doubled when the Pd doping amount is 3% and the Pd doping amount is 3% and 5%. However, No. 1 in Table 1. 5, no. According to the result of the catalyst body of No. 6, the increase in the amount of O ₂ released was slightly increased when the Pd doping amount was increased from 3% to 5%. From this, it can be seen that 1% of the Pd doping amount is not yet sufficient, and that the active point is close to saturation at 3%. Further, since the active sites are sufficiently present when the Pd doping amount is 3%, it is surmised that the improvement margin of the O ₂ emission activity due to the Pd doping beyond this becomes small as the Pd doping amount is 5%. .

  The present invention is not limited to the above-described embodiments and experimental examples, and various modifications can be made without departing from the scope of the invention. Moreover, each structure shown by each embodiment and each experiment example can be combined arbitrarily, respectively.

1 Catalyst 11 Oxide (support)
12 Precious metal element 2 Fuel reformer 21 Reactor 22 Heat source 23 Electric field application unit 24 Control unit

Claims (13)

Ln _(1-y-x) M _y A _x O _z (where Ln: rare earth element, M: transition metal element, A: noble metal element and at least one transition metal element different from M, 0.03 Catalyst body (1) having an oxide (11) represented by ≦ x ≦ 0.1, 0.1 ≦ y <0.5, 2 ≦ z ≦ 4).   The catalyst body according to claim 1, wherein the Ln contains Ce.   The M includes at least one element selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements, Group 7 elements, Group 8 elements, Group 9 elements, Group 10 elements, and Group 11 elements. The catalyst body according to claim 1 or 2.   The catalyst body according to any one of claims 1 to 3, wherein the M includes Cr.   The catalyst body according to any one of claims 1 to 4, wherein the A contains at least one element selected from the group consisting of Pt, Pd, Rh, Au, Ag, and Cu.   Said A is a catalyst body of any one of Claims 1-5 containing Pd. The oxide is Ce _(1- yx ₎ Cr _y Pd _x O ₂ (where 0.03 ≦ x ≦ 0.05, 0.1 ≦ y <0.5). The catalyst body according to any one of   The catalyst body according to any one of claims 1 to 7, further comprising a noble metal element (12) supported on the surface of the oxide.   The catalyst body according to claim 8, wherein the noble metal element supported on the surface of the oxide includes at least one selected from the group consisting of Pt, Pd, Rh, and Ru. 10. The catalyst body according to claim 1, wherein the oxide has an oxygen ion conductivity of 1 × 10 ⁻⁵ or more and 1 × 10 ⁻² S / cm or less. 11. The catalyst body according to claim 1, wherein the oxide has an electronic conductivity of 1 × 10 ⁻² or more and 1 × 10 ⁻¹ S / cm or less. Generation of H ₂ gas by decomposition of fuel containing hydrogen atoms, release of O ₂ gas using oxygen captured during decomposition of fuel containing oxygen atoms, or H ₂ gas by decomposition of fuel containing hydrogen atoms and oxygen atoms The catalyst body according to any one of claims 1 to 11, which is used to promote both generation of hydrogen and release of O ₂ gas using oxygen trapped during decomposition of the fuel containing hydrogen atoms and oxygen atoms. . A reactor (21);
The catalyst body (1) according to any one of claims 1 to 12, housed in the reactor,
A heat source (22) for heating the catalyst body;
An electric field application unit (23) for applying an electric field to the catalyst body;
A control unit (switching between supply of fuel containing at least one of hydrogen atoms and oxygen atoms into the reactor and supply stop of the fuel and controlling an electric field applied to the catalyst body by the electric field application unit ( 24)
A fuel reformer (2) comprising:

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