▎ 摘　　要

NOVELTY - Catalytic activity recovery of a manganese oxide catalyst, comprises: recovering an ozone decomposition efficiency as given in the equation 1 of the specification to greater than or equal to 90% of an initial ozone decomposition efficiency by heating, in an air atmosphere, a manganese oxide catalyst which has been used to decompose ozone and of which activity is thus reduced by greater than or equal to 10% of the initial ozone decomposition efficiency, at 80-250 degrees C. USE - The method is useful for catalytic activity recovery of a manganese oxide catalyst. ADVANTAGE - The method utilizes air-cleaning device which shows improved lifespan characteristics, that is, harmful gas including ethylene and harmful microorganisms can be removed for a long period of time. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) air-cleaning device using the catalytic activity recovery method of the manganese oxide catalyst; (2) air-cleaning system comprising the air-cleaning device; and (3) operation method of an air-cleaning device using the catalytic activity recovery method of the manganese oxide catalyst. DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of an ozone decomposition unit of an air-cleaning device. Ozone decomposition catalyst structure (1) First planar heating element (2) Thermally conductive material foil (3) Temperature sensor (4) Heat insulating material (5)