Irradiating a film of a thiophene polymer that is a pure organic compound with light allows the thiophene polymer film to act as a light absorber and catalyst that produces hydrogen peroxide from water and water-dissolved air (oxygen) at extremely high efficiency, and this film can work in alkaline water in which a film of a general-purpose inexpensive water-oxidizing catalyst, which is used as a counter electrode, is active. Provided is an environmentally compatible and simple method for producing hydrogen peroxide at extremely high efficiency, including combining a film of a catalyst for light absorption and oxygen reduction that consists of a thiophene polymer with a catalyst for water oxidation, immersing the combination in alkaline water, and irradiating the light-absorbing oxygen reduction catalyst film with light.

A modular reusable catalyst system is provided for a bi-propellant rocket engine and adaptable for a monopropellant, wherein a hydrocarbon fuel is combined with one or more catalysts, and can provide an additional convergent-divergent flow in combination with a thruster.

A modular reusable catalyst system is provided for a bi-propellant rocket engine and adaptable for a monopropellant, wherein a hydrocarbon fuel is combined with one or more catalysts, and can provide an additional convergent-divergent flow in combination with a thruster.

Disclosed herein are a catalyst composition, catalyst devices, and methods for removing formaldehyde, volatile organic compounds, and other pollutants from an air flow stream. The catalyst composition including manganese oxide, optionally one or more of alkali metals, alkaline earth metals, zinc, iron, binder, an inorganic oxide, or carbon.

Disclosed herein are a catalyst composition, catalyst devices, and methods for removing formaldehyde, volatile organic compounds, and other pollutants from an air flow stream. The catalyst composition including manganese oxide, optionally one or more of alkali metals, alkaline earth metals, zinc, iron, binder, an inorganic oxide, or carbon.

A gas treatment device that treats a gas to be treated, including oxygen, introduced at a gas inlet and that exhausts a treated gas at a gas outlet, the gas treatment device includes: a gas channel that communicates the gas inlet with the gas outlet; a blower that allows the gas to be treated to flow from the gas inlet to the gas outlet; an ultraviolet light source that is disposed in the gas channel and radiates ultraviolet light having a wavelength of 230 nm or less; a filter that is disposed at a side at which the gas outlet is located from the ultraviolet light source in the gas channel, and that adsorbs at least ozone; and a control unit that controls the blower to operate, wherein the control unit controls the blower to start a blowing operation after the ultraviolet light source starts radiating the ultraviolet light.

A gas treatment device that treats a gas to be treated, including oxygen, introduced at a gas inlet and that exhausts a treated gas at a gas outlet, the gas treatment device includes: a gas channel that communicates the gas inlet with the gas outlet; a blower that allows the gas to be treated to flow from the gas inlet to the gas outlet; an ultraviolet light source that is disposed in the gas channel and radiates ultraviolet light having a wavelength of 230 nm or less; a filter that is disposed at a side at which the gas outlet is located from the ultraviolet light source in the gas channel, and that adsorbs at least ozone; and a control unit that controls the blower to operate, wherein the control unit controls the blower to start a blowing operation after the ultraviolet light source starts radiating the ultraviolet light.

A honeycomb-structured catalyst for decomposing an organic substance, which includes a catalyst particle. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least of Ba and Sr, the B contains Zr, the M is at least one of Mn, Co, Ni, and Fe, y+z=1, 1.001≤x≤1.05, 0.05≤z≤0.2, and w is a positive value that satisfies electrical neutrality. The toluene decomposition rate is greater than 90% when toluene is decomposed using the honeycomb-structured catalyst subjected to a heat treatment at 1200° C. for 48 hours and a gas that contains 50 ppm toluene, 80% nitrogen, and 20% oxygen as a volume concentration as a target at a space velocity of 30,000/h and a catalyst temperature of 400° C.

A honeycomb-structured catalyst for decomposing an organic substance, which includes a catalyst particle. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least of Ba and Sr, the B contains Zr, the M is at least one of Mn, Co, Ni, and Fe, y+z=1, 1.001≤x≤1.05, 0.05≤z≤0.2, and w is a positive value that satisfies electrical neutrality. The toluene decomposition rate is greater than 90% when toluene is decomposed using the honeycomb-structured catalyst subjected to a heat treatment at 1200° C. for 48 hours and a gas that contains 50 ppm toluene, 80% nitrogen, and 20% oxygen as a volume concentration as a target at a space velocity of 30,000/h and a catalyst temperature of 400° C.

A water-based paint composition has the ability to decompose ozone and includes a manganese oxide-based catalyst, an activated carbon, a polyacrylate-based dispersant, a water-soluble resin, a pH adjuster, and a water-based solvent.