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.

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.

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.

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.

An object of the present invention is to provide a catalyst capable of improving the selectivity of unsaturated aldehydes and unsaturated carboxylic acids, and a catalyst containing molybdenum, antimony, bismuth, and iron, wherein an atom ratio of the antimony to the molybdenum on a surface of the catalyst is greater than an atom ratio of the antimony to the molybdenum in the entire catalyst is provided.

An object of the present invention is to provide a catalyst capable of improving the selectivity of unsaturated aldehydes and unsaturated carboxylic acids, and a catalyst containing molybdenum, antimony, bismuth, and iron, wherein an atom ratio of the antimony to the molybdenum on a surface of the catalyst is greater than an atom ratio of the antimony to the molybdenum in the entire catalyst is provided.

The present disclosure relates to an ammoxidation catalyst for propylene, a manufacturing method of the same, and an ammoxidation method of propylene using the same. Specifically, in one embodiment of the present disclosure, there is provided a catalyst having a structure in which a metal oxide is supported on a silica support having a narrow particle size distribution, and excellent wear resistance.

The present disclosure relates to an ammoxidation catalyst for propylene, a manufacturing method of the same, and an ammoxidation method of propylene using the same. Specifically, in one embodiment of the present disclosure, there is provided a catalyst having a structure in which a metal oxide is supported on a silica support having a narrow particle size distribution, and excellent wear resistance.