Air-cleaning device and air-cleaning method

An air-cleaning device for reducing harmful gases including ethylene and harmful microorganisms, the air-cleaning device comprising:

• an air inlet for intaking air from the outside;
• an ozone generating unit in which at least one ozone generator of a corona discharge ozone generator or a cold plasma ozone generator is located;
• an ozone decomposition unit for removing ozone generated in the ozone generating unit, in which a support and an ozone decomposition catalyst structure including a nano manganese oxide are located;
• and
• an air outlet for outflowing the internal air to the outside, wherein
• the nano manganese oxide is located on at least a portion of the inside and the surface of the support,
• the nano manganese oxide includes at least one of α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, or amorphous MnO2, and
• the nano manganese oxide has a shape selected from a nanorod shape, a nanofiber shape, a nano sea-urchin shape, a nanoflower shape, or a nanosheet shape.