Catalyst refers to a chemical that can increase the rate of chemical reaction without changing the chemical equilibrium, and its own mass and chemical properties are not changed before and after the chemical reaction. More than 90% of industrial processes use catalysts, such as chemical, petrochemical, biochemical, environmental protection and so on.

Most catalysts have three types of components that can be distinguished: active compositions, carriers, and co-catalysts.

Active composition is the main component of the catalyst, sometimes composed of one substance, sometimes composed of a variety of substances.

Carrier is the dispersing agent, adhesive or supporting body of the catalytic active component, and the skeleton of the loaded active component. The catalyst prepared by loading the active component and the co-catalyst component on the carrier becomes the supported catalyst.

Common carrier types: low specific surface areas are: corundum, silicon carbide, pumice, diatomite, asbestos, firebrick; High specific surface area: alumina, SiO2-Al2O3, bauxite, clay, magnesium oxide, silica gel, and activated carbon.

Co-catalyst is a small amount of substances added to the catalyst, and the auxiliary component of the catalyst. Its own activity is not active or very small, but after they are added to the catalyst, it can change the chemical composition of the catalyst, chemical structure, ion valence, acid and alkali, lattice structure, surface structure, pore structure, dispersion state, and mechanical strength, improving the activity, selectivity, stability and life of the catalyst.