• Chemical term for an element or compound which speeds a reaction but is itself left unaltered when the process is complete. Catalysis is encountered – e.g. – in reactions in planetary atmospheres and in nucleosynthesis in stars, as in the carbon cycle.
  • A substance that accelerates a chemical reaction significantly, and which is not itself consumed in the process. By the end of the reaction, a catalyst is returned to its original state. An example is the platinum utilized in a fuel cell.
  • Any agent which speeds up a process significantly.

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