Active catalytic phase is a component of a heterogeneous catalyst that is directly involved in the catalytic reaction .
Description
The term is used to denote the catalytically active component that is part of the catalyst along with other main components - the carrier and promoters . As a rule, the particle size of the active catalytic phase is in the nanoscale . The active catalytic phase can make up only a small fraction of the total mass of the catalyst, for example, the activity of reforming catalysts is provided by the presence of 0.3-0.5% of platinum in their composition. As a rule, the active phase is formed in the catalyst at the stage of its preparation, but in some cases it can also form directly during the catalytic process. So, for example, nickel and molybdenum oxides formed at the stage of preparation of hydrodesulfurization catalysts are reduced and converted into sulfides during operation, which greatly accelerate the process of hydrodesulfurization, that is, they serve as an active catalytic phase. The catalyst can lose its activity and selectivity if the active phase undergoes any structural or compositional changes, blocking by reaction products (for example, coking of oil refining catalysts), and a decrease in the active surface area due to sintering or migration of particles of the active phase.
Literature
- Setterfield C. Practical course of heterogeneous catalysis. - M .: Mir, 1984. - 520 p.
- Krylov O. V. Heterogeneous catalysis. - M.: IKC "Akademkniga", 2004. - 679 p.