An object of the present invention is to provide an exhaust gas purification catalyst composition and an exhaust gas purification catalyst, each of which includes a pyrochlore-type CeO.sub.2—ZrO.sub.2-based complex oxide having an improved oxygen storage capacity (particularly, an improved oxygen storage capacity after being exposed to a high temperature environment), and, in order to achieve the above-mentioned object, the present invention provides an exhaust gas purification catalyst composition and an exhaust gas purification catalyst, each of which contains a pyrochlore-type CeO.sub.2—ZrO.sub.2-based complex oxide that contains Y and Mg and thus exhibits an excellent oxygen storage capacity (particularly, an excellent oxygen storage capacity after being exposed to a high temperature environment).

A method includes supplying a gas containing acrolein to a fixed bed reactor including a reaction tube to produce acrylic acid by vapor phase catalytic oxidation of acrolein. The reaction tube is packed with catalysts having different activities in such a way that catalyst layers are formed in a tube axis direction. A catalyst X having the highest activity among the catalysts contained in all the catalyst layers is placed in the whole or a part of a section up to 30% of a length of all the catalyst layers from a rearmost portion on a gas outlet side toward a gas inlet side. A catalytically active component x in the catalyst X has Mo, V, and optionally Cu. When Cu is included, its amount is 0.8 mol or less per 12 mol of Mo. A specific surface area of the catalytically active component x is 15-40 m.sup.2/g.

A method includes supplying a gas containing acrolein to a fixed bed reactor including a reaction tube to produce acrylic acid by vapor phase catalytic oxidation of acrolein. The reaction tube is packed with catalysts having different activities in such a way that catalyst layers are formed in a tube axis direction. A catalyst X having the highest activity among the catalysts contained in all the catalyst layers is placed in the whole or a part of a section up to 30% of a length of all the catalyst layers from a rearmost portion on a gas outlet side toward a gas inlet side. A catalytically active component x in the catalyst X has Mo, V, and optionally Cu. When Cu is included, its amount is 0.8 mol or less per 12 mol of Mo. A specific surface area of the catalytically active component x is 15-40 m.sup.2/g.

Embodiments of the present invention include a filter element for decomposing contaminants including a substrate, and a photocatalytic composition comprising at least a photocatalyst and a co-catalyst. The embodiments of the present invention also includes a system for decomposing contaminants including a substrate, and a photocatalytic composition comprising at least a photocatalyst and a co-catalyst; and a method using the system.

Embodiments of the present invention include a filter element for decomposing contaminants including a substrate, and a photocatalytic composition comprising at least a photocatalyst and a co-catalyst. The embodiments of the present invention also includes a system for decomposing contaminants including a substrate, and a photocatalytic composition comprising at least a photocatalyst and a co-catalyst; and a method using the system.

The present invention relates to the field of catalytic cracking, and discloses a composition capable of reducing CO and NOx emissions, the preparation method and use thereof, and a fluidized catalytic cracking method. The inventive composition capable of reducing CO and NOx emissions comprises an inorganic oxide carrier, and a first metal element, optionally a second metal element, optionally a third metal element and optionally a fourth metal element supported on the inorganic oxide carrier, wherein the first metal element includes Fe and Co, and wherein the weight ratio of Fe to Co is 1:(0.1-10) on an oxide basis. The inventive composition has better hydrothermal stability and higher activity of reducing CO and NOx emissions in the flue gas from the regeneration.

The present invention relates to the field of catalytic cracking, and discloses a composition capable of reducing CO and NOx emissions, the preparation method and use thereof, and a fluidized catalytic cracking method. The inventive composition capable of reducing CO and NOx emissions comprises an inorganic oxide carrier, and a first metal element, optionally a second metal element, optionally a third metal element and optionally a fourth metal element supported on the inorganic oxide carrier, wherein the first metal element includes Fe and Co, and wherein the weight ratio of Fe to Co is 1:(0.1-10) on an oxide basis. The inventive composition has better hydrothermal stability and higher activity of reducing CO and NOx emissions in the flue gas from the regeneration.

There is provided an ammoxidation catalyst for propylene having a structure in which molybdenum (Mo) oxide is supported first, and an oxide of heterogeneous metals including bismuth (Bi) is supported later. Related methods of making and using the catalyst are also provided.

There is provided an ammoxidation catalyst for propylene having a structure in which molybdenum (Mo) oxide is supported first, and an oxide of heterogeneous metals including bismuth (Bi) is supported later. Related methods of making and using the catalyst are also provided.

Provided is a catalyst for manufacturing multi-wall carbon nanotubes, the catalyst including metal components according to <Equation> Ma:Mb=x:y, and having a hollow structure with a thickness of 0.5-10 μm. In the above equation, Ma represents at least two metals selected from Fe, Ni, Co, Mn, Cr, Mo, V, W, Sn, and Cu; Mb represents at least one metal selected from Mg, Al, Si, and Zr; x and y each represent the molar ratio of Ma and Mb; and x+y=10, 2.0≤x≤7.5, and 2.5≤y≤8.0.