Abstract: 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: CexA1-x-yByOd (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.

Abstract: 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: CexA1?x?yByOd (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.

Abstract: The present disclosure provides an ammonia synthesis catalyst including a composite oxide support containing cerium and praseodymium; and ruthenium supported on the composite oxide support, wherein a molar ratio of cerium to praseodymium ([cerium]/[praseodymium]) contained in the composite oxide support is 20/80 to 90/10.

Abstract: An exhaust gas purification catalyst includes: a support formed of alumina and yttria; and platinum and palladium that are supported on the support. An yttria content in the support is 2 mass % to 15 mass %. A content ratio of the platinum to the palladium is in a range of 1 to 10 by mass ratio. At least a portion of the platinum and at least a portion of the palladium constitute a solid solution. A diffraction peak of a (311) plane of a crystal including the platinum, the palladium and the solid solution is present at 81.5° or higher in a range of 81.2° to 82.1°, the diffraction peak being identified by an X-ray diffraction method using CuK? rays.

Abstract: An exhaust gas purification catalyst includes: a support containing alumina as a major component; and an active species fine particle containing silver sulfate as a major component and having an average crystallite size of 3 nm to less than 100 nm, in which the active species fine particle is supported on a surface of the support.