Japan Science and Technology Agency

Hiroshi Kageyama

Yoji Kobayashi

Hideo Hosono

Kazuki Nakanishi

Mikio Takano

Hiroki Yamashita

Atsushi Kitada

Naoya Masuda

George Hasegawa

Kohei Aizu

Wataru Yoshimune

Takeshi Yajima

Thibault Broux

The present invention is to provide an electron or hydride ion intake/release material comprising a lanthanoid oxyhydride represented by the formula Ln(HO) (in the formula, Ln represents a lanthanoid element) or an electron or hydride ion intake/release composition comprising at least one kind of lanthanoid oxyhydride; a transition metal-supported material wherein a transition metal is supported by the above electron or hydride ion intake/release material or electron or hydride ion intake/release composition; and a catalyst comprising the transition metal-supported material. The electron or hydride ion intake/release material or electron or hydride ion intake/release composition according to the present invention has a higher ability for intake/release of electron or hydride ion than that of a conventional hydride-containing compound, and can be used effectively as a catalyst such as a catalyst having excellent ammonia synthesis activity by supporting a transition metal thereon.

Electron or hydride ion intake/release material, electron or hydride ion intake/release composition, transition metal-supported material and catalyst, and use in relation thereto

The ammonia synthesis catalyst of the present invention, comprises: a powder of a perovskite oxyhydride having hydride (H) incorporated therein as a support; and a metal or a metal compound exhibiting a catalytic activity for ammonia synthesis, supported on the support, and the perovskite oxyhydride is represented by ATiOH(wherein A represents Ca, Sr, or Ba, and 0.1&#x2264;x&#x2264;0.6).

Ammonia synthesis catalyst and ammonia synthesis method

Provided are a macroporous titanium compound monolith and a production method thereof, the macroporous titanium compound monolith having a framework that is composed of a titanium compound other than titanium dioxide, having controlled macropores, and having electron conductivity, the titanium compound being oxygen-deficient titanium oxide, titanium oxynitride, or titanium nitride. Provided is a method including: placing a macroporous titanium dioxide monolith and a metal having titanium-reducing ability in a container, the macroporous titanium dioxide monolith having a co-continuous structure of a macropore and a framework that is composed of titanium dioxide; creating a vacuum atmosphere or an inert gas atmosphere within the container; and heating the monolith and the metal to cause gas-phase reduction that removes oxygen atom from the titanium dioxide composing the monolith by the metal acting as an oxygen getter, thereby obtaining a macroporous oxygen-deficient titanium oxide monolith having a co-continuous structure of the macropore and a framework that is composed of oxygen-deficient titanium oxide, the macroporous oxygen-deficient titanium oxide monolith having electron conductivity derived from the oxygen-deficient titanium oxide.

Macroporous titanium compound monolith and method for producing same

The method for producing a perovskite metal oxynitride of the present invention, comprises: a hydrogenation step (A) of forming a perovskite oxyhydride in which an oxide ion (O2&#x2212;) and a hydride ion (H&#x2212;) coexist, by reducing a perovskite oxide through a reductive oxygen elimination reaction using a metal hydride; and a nitriding step (B) of forming a perovskite oxynitride containing a nitride ion (N3&#x2212;) by heat-treating the perovskite oxyhydride in the presence of a nitrogen source substance at a temperature of 300&#xb0; C. or higher and 600&#xb0; C. or lower and exchanging the hydride ion (H&#x2212;) for a nitride ion (N3&#x2212;).

Method for producing perovskite metal oxynitride

[Problem] Many oxide-ion conductors exhibit high functionality at high temperatures due to the large weight and charge of oxide ions, and it has been difficult to achieve the functionality at low temperatures. [Solution] A perovskite oxide having hydride ion conductivity, at least 1 at % of the oxide ions (O) contained in a titanium-containing perovskite oxide being substituted with hydride ions (H). This oxide, in which negatively charged hydride ions (H) are used for the ionic conduction, has both hydride ion conductivity and electron conductivity. As a starting material, the titanium-containing perovskite oxide is kept together with a powder of an alkali metal or alkaline-earth metal hydride selected from LiH, CaH, SrH, and BaHin a temperature range of 300&#xb0; C. or higher and lower than the melting point of the hydride in a vacuum or an inert gas atmosphere to substitute some of the oxide ions in the oxide with the hydride ions, resulting in the introduction of the hydride ions into oxygen sites.

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Kyoto, Japan

Hiroshi Kageyama