A powdered catalyst material on a titanium oxide basis. The powdered catalyst material includes a combined content of at least 90 wt.-% of a hydrated titanium oxide having the general formula TiO.sub.(2-x)(OH).sub.2x, with 0<x≤1, (calculated as TiO.sub.2), and a silicon dioxide and hydrated precursors of the silicon dioxide (calculated as SiO.sub.2). A weight ratio of TiO.sub.2/SiO.sub.2, determined for TiO.sub.2 and SiO.sub.2 respectively, is at least 3 and less than 30. The wt.-% is based on a total weight of the catalyst material after the catalyst material has been dried at 105° C. for at least 2 hours. The powdered catalyst material has a specific surface area of >300 m.sup.2/g and an isoelectric point of from 4.0 to 7.0.

An object of the present invention is to provide a catalyst ensuring that when a gas-phase catalytic oxidation reaction of a material substance is conducted using a catalyst to produce a target substance, the pressure loss and coking are suppressed and the target substance can be produced in high yield. The present invention is related to a ring-shaped catalyst having a straight body part and a hollow body part, which is used when a gas-phase catalytic oxidation reaction of a material substance is conducted to produce a target substance, wherein a length of the straight body part is shorter than a length of the hollow body part and at least at one end part, a region from an end part of the straight body part to an end part of the hollow body part is concavely curved.

An object of the present invention is to provide a catalyst ensuring that when a gas-phase catalytic oxidation reaction of a material substance is conducted using a catalyst to produce a target substance, the pressure loss and coking are suppressed and the target substance can be produced in high yield. The present invention is related to a ring-shaped catalyst having a straight body part and a hollow body part, which is used when a gas-phase catalytic oxidation reaction of a material substance is conducted to produce a target substance, wherein a length of the straight body part is shorter than a length of the hollow body part and at least at one end part, a region from an end part of the straight body part to an end part of the hollow body part is concavely curved.

An ammonia synthesis catalyst, includes a composite oxide carrier in which at least one additive metal element selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), and tin (Sn) is solid-solutionized in a composite oxide containing cerium (Ce) and a lanthanide other than Ce and having a composition represented by the following formula:

Ce.sub.xA.sub.1−x−yB.sub.yO.sub.d

(in the formula, A represents a lanthanide other than Ce, B represents the additive metal element, x represents a molar fraction of Ce, y represents a molar fraction of the additive metal element, 1−x−y represents a molar fraction of a lanthanide other than Ce, x and y satisfy 0.1≤x≤0.9, 0.01≤y≤0.3, and 0.11≤x+y≤0.91, d represents a molar ratio of oxygen atoms, and 1.5≤d≤2 is satisfied); and ruthenium (Ru) supported on the composite oxide carrier.

An ammonia synthesis catalyst, includes a composite oxide carrier in which at least one additive metal element selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), and tin (Sn) is solid-solutionized in a composite oxide containing cerium (Ce) and a lanthanide other than Ce and having a composition represented by the following formula:

Ce.sub.xA.sub.1−x−yB.sub.yO.sub.d

(in the formula, A represents a lanthanide other than Ce, B represents the additive metal element, x represents a molar fraction of Ce, y represents a molar fraction of the additive metal element, 1−x−y represents a molar fraction of a lanthanide other than Ce, x and y satisfy 0.1≤x≤0.9, 0.01≤y≤0.3, and 0.11≤x+y≤0.91, d represents a molar ratio of oxygen atoms, and 1.5≤d≤2 is satisfied); and ruthenium (Ru) supported on the composite oxide carrier.

Porous alumina having excellent heat resistance and coking resistance is provided. The porous alumina can include silica and barium oxide added to aluminum oxide, wherein a ratio of SiO2 addition amount to a total mass of aluminum oxide and SiO2 addition amount is defined as SiO2 addition ratio (mass %), a ratio of BaO addition amount to a total mass of aluminum oxide and SiO2 addition amount is defined as BaO addition ratio (mass %), when the SiO2 addition ratio is within a range of 3 mass % or less and the BaO addition ratio is within a range of 14 mass % or less, the silica and the barium oxide are respectively added to the aluminum oxide so that a specific surface area of the porous alumina measured by a measuring method after heat treatment is equal to or larger than a reference specific surface area of reference porous alumina.

Porous alumina having excellent heat resistance and coking resistance is provided. The porous alumina can include silica and barium oxide added to aluminum oxide, wherein a ratio of SiO2 addition amount to a total mass of aluminum oxide and SiO2 addition amount is defined as SiO2 addition ratio (mass %), a ratio of BaO addition amount to a total mass of aluminum oxide and SiO2 addition amount is defined as BaO addition ratio (mass %), when the SiO2 addition ratio is within a range of 3 mass % or less and the BaO addition ratio is within a range of 14 mass % or less, the silica and the barium oxide are respectively added to the aluminum oxide so that a specific surface area of the porous alumina measured by a measuring method after heat treatment is equal to or larger than a reference specific surface area of reference porous alumina.

Provided is a method for producing a photocatalyst electrode for water decomposition that exhibits excellent detachability between the substrate and the photocatalyst layer and exhibits high photocurrent density. The method for producing a photocatalyst electrode for water decomposition of the invention includes: a metal layer forming step of forming a metal layer on one surface of a first substrate by a vapor phase film-forming method or a liquid phase film-forming method; a photocatalyst layer forming step of forming a photocatalyst layer by subjecting the metal layer to at least one treatment selected from an oxidation treatment, a nitriding treatment, a sulfurization treatment, or a selenization treatment; a current collecting layer forming step of forming a current collecting layer on a surface of the photocatalyst layer, the surface being on the opposite side of the first substrate; and a detachment step of detaching the first substrate from the photocatalyst layer.

Provided is a method for producing a photocatalyst electrode for water decomposition that exhibits excellent detachability between the substrate and the photocatalyst layer and exhibits high photocurrent density. The method for producing a photocatalyst electrode for water decomposition of the invention includes: a metal layer forming step of forming a metal layer on one surface of a first substrate by a vapor phase film-forming method or a liquid phase film-forming method; a photocatalyst layer forming step of forming a photocatalyst layer by subjecting the metal layer to at least one treatment selected from an oxidation treatment, a nitriding treatment, a sulfurization treatment, or a selenization treatment; a current collecting layer forming step of forming a current collecting layer on a surface of the photocatalyst layer, the surface being on the opposite side of the first substrate; and a detachment step of detaching the first substrate from the photocatalyst layer.

A process includes reacting a feed stream containing ethanol and optionally acetaldehyde in a dehydration reactor in the presence of a dehydration catalyst system having a Group 4 or Group 5 metal oxide and a support. The process includes obtaining a product stream containing butadiene from the dehydration reactor. Another process includes reacting a feed stream containing ethanol and optionally acetaldehyde in a dehydration reactor in the presence of a dehydration catalyst system containing a tungsten oxide supported on a zeolite or a tantalum oxide supported on a zeolite. The process includes obtaining a product stream containing butadiene from the dehydration reactor.