katalytti

Katalytti, in Finnish, refers to the chemical concept of a catalyst: a substance that increases the rate of a chemical reaction without undergoing permanent chemical change. In chemistry, catalysts work by providing an alternative reaction pathway with a lower activation energy, allowing more particles to react at a given temperature.

Catalysts can be classified by phase. Homogeneous catalysts are in the same phase as the reactants, usually a liquid, while heterogeneous catalysts are in a different phase, often a solid. Enzymes are biological catalysts that operate under mild conditions.

Catalysts function by binding reactants to active sites, stabilizing transition states, or forming intermediates that facilitate the transformation. They do not change the overall thermodynamics of a reaction; they speed up attainment of equilibrium by lowering the activation barrier. Catalysts can influence selectivity and yield by favoring certain reaction pathways and products.

Industrially, catalysts are central to many processes. The Haber-Bosch process uses an iron-based catalyst to fix nitrogen. The contact process uses vanadium oxide to catalyze sulfuric acid production. Catalytic cracking often relies on zeolites. Automotive catalytic converters use platinum-group metals to reduce emissions. In electrochemistry, catalysts enable fuel cells and other reactions.

Catalysts can be poisoned or deactivated by impurities, heat, or sintering, and may require regeneration or replacement. Ongoing research seeks to improve efficiency, durability, and selectivity, with advances in nanomaterials, single-atom catalysts, and other designs that aim to reduce energy use and emissions.