The present invention relates to entangled-type carbon nanotubes which have a bulk density of 31 kg/m.sup.3 to 85 kg/m.sup.3 and a ratio of tapped bulk density to bulk density of 1.37 to 2.05, and a method for preparing the entangled-type carbon nanotubes.

The present invention is directed to the preparation of a cobalt containing catalyst, a precipitate as an intermediate product, a Fischer-Tropsch catalyst and a process for producing normally gaseous, normally liquid and optionally normally solid hydrocarbons from synthesis gas. The precipitate and catalyst comprise crystalline Co(OH)(CO3)0.5, the crystals are needle shaped and have a surface area of at least 80 m.sup.2/g dry precipitate.

The present invention relates to a method for preparing carbon nanotubes, the method including: preparing a support including AlO(OH) by primary heat treatment of Al(OH).sub.3; preparing an active carrier by supporting a mixture including a main catalyst precursor and a cocatalyst precursor on the support; drying the active carrier through multi-stage drying including vacuum drying; preparing a supported catalyst by secondary heat treatment of the dried active support; and preparing carbon nanotubes in the presence of the supported catalyst, and the carbon nanotubes prepared by the method as described above can remarkably improve conductivity.

The present invention relates to a catalyst for the oxidation of hydrocarbon and the selective catalytic reduction of nitrogen oxides, the catalyst comprising a substrate comprising an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end and a plurality of passages defined by internal walls of the substrate extending therethrough; and a coating disposed on the surface of the internal walls of the substrate, wherein the surface de-fines the interface between the passages and the internal walls, wherein the coating comprises a platinum group metal component supported on a first oxidic material and further comprises a mixed oxide of vanadium and one or more of iron, erbium, bismuth, cerium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, promethium, samarium, scandium, terbium, thulium, ytterbium, yttrium, molybdenum, tungsten, manganese, cobalt, nickel, copper, aluminum and antimony, wherein the mixed oxide is supported on a second oxidic material.

Methods and compositions related to a selective catalytic reduction catalyst comprising iron and vanadium, wherein the vanadium is present as (1) one or more vanadium oxides, and (2) metal vanadate of the form Fe.sub.xM.sub.yVO.sub.4 where x=0.2 to 1 and y=1x, and where M comprises one or more non-Fe metals when y>0.

The moisture-resistant catalyst for air pollution remediation is a catalyst with moisture-resistant properties, and which is used for removing nitrogen compound pollutants, such as ammonia (NH.sub.3), from air. The moisture-resistant catalyst for air pollution remediation includes at least one metal oxide catalyst, at least one inorganic oxide support for supporting the at least one metal oxide catalyst, and a porous framework for immobilizing the at least one metal oxide catalyst and the at least one inorganic oxide support, where the porous framework is moisture-resistant. As non-limiting examples, the at least one metal oxide catalyst may be supported on the at least one inorganic oxide support by precipitation, impregnation, dry milling, ion-exchange or combinations thereof. The at least one metal oxide catalyst supported on the at least one inorganic oxide support may be physically embedded in the porous framework.

The present invention relates to a supported catalyst that can be used to produce a carbon nanotube aggregate with high bulk density, a method for preparing the supported catalyst, a carbon nanotube aggregate produced using the supported catalyst, and a method for producing the carbon nanotube aggregate. According to the present invention, the bulk density of the carbon nanotube aggregate is easily controllable. Therefore, the carbon nanotube aggregate is suitable for use in various fields.

A photocatalytic member comprises a base and a photocatalytic layer fixed on the base. The photocatalytic layer comprises first photocatalyst particles being visible light responsive photocatalyst particles for hydrogen generation, second photocatalyst particles being visible light responsive photocatalyst particles for oxygen generation, and conductive particles which are provided between the first photocatalyst particle and the second photocatalyst particle, have Fermi level at a negative position relative to an electronic energy level at the upper end of the valence band of the first photocatalyst particle and at a positive position relative to an electronic energy level at the bottom end of the conduction band of the second photocatalyst particle, and are able to store an electron and a hole. In the photocatalytic layer, the conductive particles are located to be coupled to both the first photocatalyst particles and the second photocatalyst particles.

The present invention relates to entangled-type carbon nanotubes which have a bulk density of 31 kg/m.sup.3 to 85 kg/m.sup.3 and a ratio of tapped bulk density to bulk density of 1.37 to 2.05, and a method for preparing the entangled-type carbon nanotubes.

An embodiment of the present invention provides a method for manufacturing multi-wall carbon nanotubes, the method comprising the steps of: (a) dissolving a metal precursor in a solvent to prepare a precursor solution; (b) perform thermal decomposition while spraying the precursor solution into a reactor, thereby forming a catalyst powder; and (c) introducing the catalyst powder into a fluidized-bed reactor heated to 600-900 C. and spraying a carbon-based gas and a carrier gas to synthesize multi-wall carbon nanotubes from the catalyst powder, wherein steps (a) to (c) are performed in a continuous type and wherein the catalyst powder contains metal components according to equation 1 below. <Equation 1> Ma:Mb=x:y, wherein 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, 2.0x7.5, and 2.5y8.0.