Photocatalyst is a general term for photo-semiconductor materials with photocatalytic function represented by nano-scale titanium dioxide(TIO2).It is one of the safest materials to control indoor environmental pollution in the world. It is coated on the surface of the substrate, and under the action of ultraviolet light(UV) and visible light, it produces a strong catalytic degradation function: it can effectively degrade air Poisonous and harmful gases; it can effectively kill a variety of bacteria, and can decompose and harmlessly treat the toxins released by bacteria or fungi; it also has the functions of formaldehyde removal, deodorization, anti-pollution, and air purification.