Catalyst manufacturer tells you what is the best definition of catalyst

A catalyst is a substance that changes the reaction rate but does not change the total standard Gibbs free energy of the reaction. The role of a catalyst in a chemical reaction is called catalysis. Catalysts are also called catalysts in the industry. The composition, chemical properties and quality of the catalyst itself do not change before and after the reaction; its relationship with the reaction system is like the relationship between a lock and a key, and it has a high degree of selectivity.

Catalysts do not catalyze all chemical reactions. For example, manganese dioxide catalyzes the thermal decomposition of potassium chlorate and accelerates the rate of chemical reactions, but it does not necessarily catalyze other chemical reactions. Certain chemical reactions are not the only catalyst. For example, potassium chlorate can be catalyzed by the thermal decomposition of magnesium oxide, iron oxide, copper oxide, and so on. Moreover, a chemical reaction does not have only one catalyst. For example, red brick powder or copper oxide can also be used as a catalyst when preparing oxygen from potassium chlorate.

There is also a saying that catalysts participate in chemical reactions. In a general chemical reaction, the role of the catalyst is to reduce the activation energy required for the reaction to occur, essentially turning a relatively difficult reaction into two easily occurring chemical reactions. In these two reactions, the catalyst plays the role of the reactant in the first reaction, and the catalyst plays the role of the product in the second reaction. Therefore, from the perspective of the overall reaction equation, the catalyst does not change before and after the reaction.

The substances originally generated by the catalyst due to the chemical reaction will regenerate the original catalyst in the subsequent further reactions, that is, the quality and chemical properties mentioned above have not changed before and after the reaction.

Generally speaking, a catalyst refers to a substance that participates in the middle course of a chemical reaction and can selectively change the rate of a chemical reaction, while its quantity and chemical properties remain basically unchanged before and after the reaction. Generally, the role of catalysts in accelerating chemical reactions and making the reaction reach chemical equilibrium as soon as possible is called catalysis.

There are many types of catalysts, which can be divided into liquid catalysts and solid catalysts according to their state; according to the phase state of the reaction system, they are divided into homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts include acids, bases, soluble transition metal compounds and peroxide catalysts. Heterogeneous catalysts include solid acid catalysts, organic base catalysts, metal catalysts, metal oxide catalysts, complex catalysts, rare earth catalysts, molecular sieve catalysts, biocatalysts, nano catalysts, etc.; according to the type of reaction, they are divided into polymerization, polycondensation, and esterification. , Acetalization, hydrogenation, dehydrogenation, oxidation, reduction, alkylation, isomerization and other catalysts; according to the size of the role is also divided into main catalysts and co-catalysts.