The carbon dioxide exhaled by humans has been scientifically proven to be a substance that attracts mosquitoes to the human body. The photocatalyst mosquito killer can generate the light, heat, carbon dioxide, water vapor, and flowing air that mosquitoes like during operation, simulating human respiration to lure mosquitoes, attracting them away from their surroundings and falling into the mosquito trap cyclone, causing them to dehydrate and air dry and die. Photocatalysts can also purify air, sterilize and disinfect.