Heteropoly acids with Keggin structure generally refer to inorganic compounds expressed in the following general chemical formulas. They are one of the most active catalysts used in acid catalytic reactions and redox reactions. It has good catalytic properties for the hydration and esterification of olefins, etherification of epoxides, alkylation of olefins and aldehydes, epoxidation of olefins and alkyl aromatization, etc. It has wide applications in petrochemical industry.

In 1993, the advent of LED brought a significant revolution in the field of lighting. Then in 1996, the first white LED solid light source was developed by using GaN-LED chip and YAG: Ce³⁺ phosphor to emit white light. Since then, white LED has surpassed incandescent lamp, fluorescent lamp and other lighting sources with the advantages of small size, low calorific value, low power consumption, long life, fast reaction speed, environmental protection and planar packaging.

China's tungsten reserves are the first in the world, but with wolframite resources becoming scarce, the mining focus has gradually shifted to scheelite. How to develop efficient scheelite smelting process has become an important subject of tungsten metallurgy.

With the rapid development of automotive industry, sulfur pollution caused by combustion of automotive fuels is becoming more and more serious. Strict sulfur content standards for gasoline and diesel have been formulated in various countries and regions of the world. Hydrodesulfurization (HDS) is usually used in industry to remove sulfides from gasoline and diesel.