Abstract: A fluid purifying device having various embodiments, each of which is capable of removing airborne molecules, such as contaminants, malodors, volatile organic compounds (VOCs), pathogens, mold and bacteria, using the combination of visible light and a photocatalyst that has been either treated with a photosensitizer or has been treated in some other manner to lower the energy required to activate the photocatalyst (i.e., by having it generate free radicals) to that emitted by visible light bulbs. Preferably, the device is an air purifying device; however, the device could also be used as a liquid (e.g., water) purifying device.