Air purifier

An air purifier comprises an air inlet area and an air outlet area, and the air inlet area is connected the air outlet area through an air liquid filtering and oxygen activating area and a gas-solid and liquid separation area. A liquid in the air liquid filtering and oxygen activating area at least comprises water, glycerin or an ionic liquid, an oxygen activating catalyst is added to the liquid and activates oxygen in air to form highly active oxygen, the catalyst is a solid heterogeneous phase catalyst, and preferably selects a netted, cribriform, annular or honeycomb solid-molded catalyst, and the specific surface area is not lower than 150m /g. The air purifier does not use a filter membrane, an adsorption material or any other filtering materials, and also does not use high voltage electric fields, strong ultraviolet rays, peroxides or halogen compounds causing secondary pollutants to disinfect or sterilize. The air purifier is suitable for indoor purification of a limited space, and can also be used for outdoor air purification of very large even infinite spaces.