At present, the role of the catalyst is not fully understood. In most cases, it is believed that the catalyst itself participates in the chemical reaction along with the reactants, reducing the activation energy required for the reaction. Some catalytic reactions are due to the formation of easily decomposable "intermediates", when the decomposition of the catalyst restores the original chemical composition, the original reactants become products.

Definition: According to the definition proposed by IUPAC in 1981, a catalyst is a substance that accelerates the rate of a reaction without changing the standard Gibbs free enthalpy change of that reaction. This effect is called catalysis. A screening involving a catalyst is a catalytic reaction.

From the multi-component system, some of the substances are extracted with appropriate liquid agents (or water) to make catalysts with porous structures. For example, the skeleton nickel catalyst is made by melting a quantity of nickel and aluminum in an electric furnace, and the melt becomes an alloy after cooling.

Each method for making catalysts is actually a combination of a series of operating units. For convenience, the name of the key and distinctive unit of operation is used as the name of the manufacturing method. The traditional methods include mechanical mixing, precipitation, impregnation, solution evaporation, thermal melting, immersion, ion exchange, etc. The new methods developed now include chemical bonding, fibrillation, etc.

The heavy metal content on the catalytic cracking balancing agent in China are more than 10 mg/g, so foreign sulfur reduction additives are not necessarily applicable to domestic catalytic cracking units. The Institute of Petrochemical Sciences has studied the transformation mechanism of sulfide in the catalytic cracking process, as well as the transformation process of sulfide adsorption by new materials, and developed desulfurization additives that can process raw materials containing high nickel and high vanadium.

At this stage, researchers mainly improve the performance of catalytic cracking tower bottom oil cracking additives by improving their acid properties and pore structure. In response to the characteristics of seasonal demand for diesel and high gasoline inventory.