Photocatalyst is a photo-catalytic photo-semiconductor material represented by nano-sized titanium dioxide. It is coated on the surface of the substrate and produces strong catalytic degradation under the action of ultraviolet light: it can effectively degrade toxic and harmful gases in the air. It can effectively kill a variety of bacteria, can decompose bacteria and fungi and harmless treatment; at the same time, it has the functions of removing formaldehyde, deodorizing and purifying air. However, if the filter plate of the photocatalyst is coated and the ultraviolet lamp is not installed, the effect is equal to none, and the ultraviolet radiation for a long time is harmful to the human body. Cold catalyst, also known as natural catalyst, can catalyze reaction under normal temperature conditions, and decompose various harmful and odorous gases into harmless and odorless substances under normal temperature and pressure, from simple physical adsorption to chemical adsorption, and decompose while adsorbing. Except formaldehyde, benzene, xylene, toluene, TVOC and other harmful gases to form water and carbon dioxide. In the catalytic reaction process, the cold catalyst itself does not directly participate in the reaction. After the reaction, the cold catalyst does not change and does not lose, and it plays a long-term role. The cold catalyst itself is non-toxic, non-corrosive, non-combustible, and the reaction product is water and carbon dioxide, which does not cause secondary pollution, which greatly prolongs the service life of the adsorbent material.