promoter (in catalysis) (rus. промотор (в катализе)) — substance that is added to a catalyst in small amounts in order to improve its properties such as activity, selectivity or stability.

Description

Improving the properties of a catalyst by adding a promoter far exceeds the effect that could be achieved by the action of the promoter alone; the promoter itself may not necessarily possess catalytic activity. In general, promoters can be categorised, according to their purpose, into two groups: 1) facilitating the desired reaction, i.e., increasing the activity of the catalyst, and 2) suppressing the unwanted processes, i.e., increasing the selectivity of the catalyst. Promoters of the first group are distinguished into structure forming and activating. Structure-forming promoters, as a rule, are inert substances that are present in the catalyst in the form of small particles that prevent sintering of the particles of the active catalytic phase , which prevents the reduction of the active surface during catalysis. Activating promoters can create more active sites, influence the electronic structure of the active phase, etc. An example is the iron catalyst for ammonia synthesis, containing aluminium oxide (structure-forming additive) and potassium oxide (activator) as promoters.

Authors

  • Smirnov Andrey V.
  • Tolkachev Nikolay N.

Sources

  1. Manual of Symbols and Terminology // Pure Appl. Chem. 1976. V. 46. P. 71.
  2. Setterfield Ch. Practical Course of Heterogeneous Catalysis (in Russian). - Moscow, Mir, 1984, 520 pp.
  3. Krylov O. V. Heterogeneous catalysis(in Russian). —Moscow: IKC «Akademkniga», 2004. — 679 pp.

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