An object of the present invention is to provide a method for producing metal oxide particles, in which metal oxide particles with high photocatalytic activity is produced, and a production apparatus therefor. The above object can be achieved by using a method for producing metal oxide particles, which includes subjecting a reaction gas containing metal chloride and an oxidizing gas containing no metal chloride in a reaction tube (11) to preheating, and then subjecting a combined gas composed of the reaction gas and the oxidizing gas to main heating in a main heating region (A) apart from the downstream side of the junction (5b), wherein the time until the combined gas from the junction (5b) arrives at the upstream end (A1) of the main heating region (A) is adjusted to be less than 25 milliseconds.

A visible-light-responsive photocatalyst powder includes a tungsten oxide powder. When the tungsten oxide powder is measured by X-ray diffractometry, (1) among intensity ratios of a peak A (2=22.8 to 23.4), a peak B (2=23.4 to 23.8), a peak C (2=24.0 to 24.25), and a peak D (2=24.25 to 24.5), an A/D ratio and a B/D ratio each fall within a range of 0.5 to 2.0, and a C/D ratio falls within a range of 0.04 to 2.5, (2) an intensity ratio (E/F) of a peak E (2=33.85 to 34.05) to a peak F (2=34.05 to 34.25) falls within a range of 0.1 to 2.0, and (3) an intensity ratio (G/H) of a peak G (2=49.1 to 49.7) to a peak H (2=49.7 to 50.3) falls within a range of 0.04 to 2.0, and the tungsten oxide powder has a BET specific surface area in a range of 1.5 to 820 m.sup.2/g.

A visible-light-responsive photocatalyst powder includes a tungsten oxide powder. When the tungsten oxide powder is measured by X-ray diffractometry, (1) among intensity ratios of a peak A (2=22.8 to 23.4), a peak B (2=23.4 to 23.8), a peak C (2=24.0 to 24.25), and a peak D (2=24.25 to 24.5), an A/D ratio and a B/D ratio each fall within a range of 0.5 to 2.0, and a C/D ratio falls within a range of 0.04 to 2.5, (2) an intensity ratio (E/F) of a peak E (2=33.85 to 34.05) to a peak F (2=34.05 to 34.25) falls within a range of 0.1 to 2.0, and (3) an intensity ratio (G/H) of a peak G (2=49.1 to 49.7) to a peak H (2=49.7 to 50.3) falls within a range of 0.04 to 2.0, and the tungsten oxide powder has a BET specific surface area in a range of 1.5 to 820 m.sup.2/g.

A catalyst for the carbonylation of dimethyl ether to methyl acetate. The catalyst comprises a zeolite, such as a mordenite zeolite, at least one Group IB metal, such as copper, and/or at least one Group VIII metal, such as iron, and at least one Group IIB metal, such as zinc. Such a catalyst with combined metals provides enhanced catalytic activity, improved stability, and improved selectivity to methyl acetate, and does not require a halogen promoter, as compared to a metal-free or copper only zeolite.

A catalyst for the carbonylation of dimethyl ether to methyl acetate. The catalyst comprises a zeolite, such as a mordenite zeolite, at least one Group IB metal, such as copper, and/or at least one Group VIII metal, such as iron, and at least one Group IIB metal, such as zinc. Such a catalyst with combined metals provides enhanced catalytic activity, improved stability, and improved selectivity to methyl acetate, and does not require a halogen promoter, as compared to a metal-free or copper only zeolite.

This invention relates to a cobalt-based catalyst on a metal structure for selective production of synthetic oil via Fischer-Tropsch reaction, a method of preparing the same and a method of selectively producing synthetic oil using the same, wherein zeolite, cobalt and a support are mixed and ground to give a catalyst sol, which is then uniformly thinly applied on the surface of a metal structure using a spray-coating process, thereby preventing generation of heat during Fischer-Tropsch reaction and selectively producing synthetic oil having a carbon chain shorter than that of wax. This catalyst is prepared by burning a powder mixture obtained by melt infiltration of a cobalt hydrate and a metal oxide support to give a catalyst powder including cobalt oxide/metal oxide support; hybridizing the catalyst powder including cobalt oxide/metal oxide support with a zeolite powder to give a hybrid catalyst powder; mixing the hybrid catalyst powder with an organic binder and an inorganic binder and grinding the mixed hybrid catalyst powder to give a hybrid catalyst sol; spray-coating a metal structure surface-treated with alumina by atomic layer deposition with the hybrid catalyst sol; and thermally treating the metal structure spray-coated with the hybrid catalyst sol.

This invention relates to a cobalt-based catalyst on a metal structure for selective production of synthetic oil via Fischer-Tropsch reaction, a method of preparing the same and a method of selectively producing synthetic oil using the same, wherein zeolite, cobalt and a support are mixed and ground to give a catalyst sol, which is then uniformly thinly applied on the surface of a metal structure using a spray-coating process, thereby preventing generation of heat during Fischer-Tropsch reaction and selectively producing synthetic oil having a carbon chain shorter than that of wax. This catalyst is prepared by burning a powder mixture obtained by melt infiltration of a cobalt hydrate and a metal oxide support to give a catalyst powder including cobalt oxide/metal oxide support; hybridizing the catalyst powder including cobalt oxide/metal oxide support with a zeolite powder to give a hybrid catalyst powder; mixing the hybrid catalyst powder with an organic binder and an inorganic binder and grinding the mixed hybrid catalyst powder to give a hybrid catalyst sol; spray-coating a metal structure surface-treated with alumina by atomic layer deposition with the hybrid catalyst sol; and thermally treating the metal structure spray-coated with the hybrid catalyst sol.

Disclosed is a method for providing improved hydrogenation activity by pretreating a catalyst in a three-step manner before selective hydrogenation of unsaturated hydrocarbons in an aromatic fraction in the presence of an oxide-type bimetallic (particularly nickel-molybdenum) supported catalyst.

Disclosed is a method for providing improved hydrogenation activity by pretreating a catalyst in a three-step manner before selective hydrogenation of unsaturated hydrocarbons in an aromatic fraction in the presence of an oxide-type bimetallic (particularly nickel-molybdenum) supported catalyst.

A composition of an indium oxide catalyst including an alkali dopant and a method for producing an indium oxide catalyst including an alkali dopant. The alkali dopant may include a cation of Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, and Fr.sup.+. The method for producing the indium oxide catalyst including an alkali dopant includes mixing a solution of an indium salt with a base to form precipitated indium hydroxide, contacting the precipitated indium hydroxide with a solution including an alkali metal salt to produce an indium hydroxide solution, and calcinating the indium hydroxide solution to form indium oxide; thereby forming the indium oxide catalyst including an alkali dopant.