There are many kinds of catalysts

1. According to the state, it can be divided into liquid catalyst and solid catalyst;

2. Homogeneous catalysts include acid, base, soluble transition metal compounds and peroxide catalysts. Heterogeneous catalysts include solid acid catalyst, organic base catalyst, metal catalyst, metal oxide catalyst, complex catalyst, rare earth catalyst, molecular sieve catalyst, biocatalyst, nano catalyst, etc;

3. According to the reaction type, it can be divided into polymerization, polycondensation, esterification, acetalization, hydrogenation, dehydrogenation, oxidation, reduction, alkylation, isomerization and other catalysts;

4. According to the action, it can be divided into main catalyst and cocatalyst.