A steam reforming catalyst that promotes production of hydrogen from a gas containing a hydrocarbon in the presence of steam includes a carrier and two or more catalyst metals supported on the carrier and including a first metal and a second metal. The first metal includes Ni, the second metal includes at least one of Co and Ru, and the carrier is represented by LaNbO.sub.4 or La.sub.1-xSr.sub.xNbO.sub.4 where x is in a range of 0<x0.12.

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.

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.

A method of preparing butadiene that includes supplying butene, oxygen, nitrogen, and steam into a reactor filled with a metal oxide catalyst, and performing an oxidative dehydrogenation reaction at a temperature of 300 to 450 C. as a reaction step; after the reaction step, maintaining supplying the butene, oxygen, nitrogen, and steam within a range within which the flow rate change of the butene, oxygen, nitrogen, and steam is less than 40%, or stopping supplying the butene, and cooling the reactor to a temperature range of 200 C. or lower and higher than 70 C. as a first cooling step; and after the first cooling step, stopping supplying the butene, oxygen, nitrogen, and steam or stopping at least supplying the butene, and cooling the reactor to a temperature of 70 C. or lower as a second cooling step.

A method of preparing butadiene that includes supplying butene, oxygen, nitrogen, and steam into a reactor filled with a metal oxide catalyst, and performing an oxidative dehydrogenation reaction at a temperature of 300 to 450 C. as a reaction step; after the reaction step, maintaining supplying the butene, oxygen, nitrogen, and steam within a range within which the flow rate change of the butene, oxygen, nitrogen, and steam is less than 40%, or stopping supplying the butene, and cooling the reactor to a temperature range of 200 C. or lower and higher than 70 C. as a first cooling step; and after the first cooling step, stopping supplying the butene, oxygen, nitrogen, and steam or stopping at least supplying the butene, and cooling the reactor to a temperature of 70 C. or lower as a second cooling step.

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.

Provided is a nitrogen oxide (NO.sub.X) reduction catalyst including an active site including at least one of a metal vanadate expressed by [Chemical Formula 1] and a metal vanadate expressed by [Chemical Formula 2], and a support for loading the active site thereon.

(M.sub.1).sub.XV.sub.2O.sub.X+5[Chemical Formula 1] (where M.sub.1 denotes one selected from among manganese (Mn), cobalt (Co), and nickel (Ni), and X denotes a real number having a value between 1 and 3.)

(M.sub.2).sub.YVO.sub.4[Chemical Formula 2] (where M.sub.2 denotes one selected from among lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu), and Y denotes a real number having a value between 0.5 and 1.5.)

Selective alloy corrosion is used to synthesize a robust and ultrafine mesoporous NiFeMn-based metal/metal oxide oxygen evolving catalyst with ligament and pore sizes in the range of 10 nm and a BET surface area of 43 m.sup.2/g. As an oxygen evolving catalyst, the mesoporous catalyst exhibits high stability (>264 hours) at a high current density (500 mA/cm.sup.2) with a low overpotential (360 mV) using a moderate electrolyte concentration (1 M KOH). The catalyst is made from non-precious metals and its fabrication is straight forward and directly applicable to large-scale synthesis.

An enamel composition having improved cleaning performance, a method of preparing the enamel composition, and a cooking device having the enamel composition are disclosed. The enamel composition includes glass frit and a metal oxide catalyst, wherein the metal oxide catalyst includes at least one of a unary metal oxide or a binary metal oxide, thereby allowing cleaning at room temperature while exhibiting good fouling resistance to allow easy removal of oil contaminants, such as chicken fat.