active catalytic phase otherwise active catalytic component (rus. каталитическая фаза, активная otherwise активный каталитический компонент) — component of a heterogeneous catalyst directly participating in a catalytic reaction.


The term refers to a catalytically active component, being a part of a catalyst along with the other major components: a carrier and promoters. Usually, the particle size of the active catalytic phase belongs to the nanoscale. The active catalytic phase can have only a small share in the total weight of the catalyst, for example, the activity of reforming catalysts is ensured by the presence in their composition of 0.3-0.5% of platinum. Typically, the active phase is formed in the catalyst at the stage of its preparation, but in some cases it can also be formed directly during the catalytic process. For example, the nickel and molybdenum oxides formed at the stage of hydrodesulphurisation catalyst preparation get reduced in the process and turn into sulphides that accelerate hydrodesulphurisation by many times, i.e. serve as active catalytic phase. A catalyst may lose its activity and selectivity if the active phase is subjected to any structural changes or changes in composition, or is blocked by reaction products (e.g. coking of refinery catalysts), or if the active surface area is reduced as a result of sintering or migration of the active phase particles.


  • Smirnov Andrey V.
  • Tolkachev Nikolay N.


  1. Setterfield Ch. Heterogeneous Catalysis in Practice. - New York: McGraw-Hill, 1980. - p. 416.
  2. O.V. Krylov Heterogeneous Catalysis. - M.: PTC "Akademkniga", 2004. - 679 pp.

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