Nickel oxide is a p-type semiconductor material with a band gap of 3.7eV. In traditional industries, it is often used as a photocatalyst, a cathode material for nickel-iron batteries, etc. Nickel oxide is used as a pigment for ceramics and glass. The enamel industry is used as an adhesive and colorant for enamels. The ceramic industry is used as a raw material for pigments. It is used as a raw material for nickel-zinc ferrite in the production of magnetic materials. In the glass industry, it is used as a colorant for brown glass and picture tube glass bulbs, and is also a raw material for the manufacture of nickel salts and nickel catalysts.