catalysis

History

The word 'catalysis' was proposed by Jöns Berzelius in 1836, observing the acceleration of reactions in the presence of certain substances.

How it works

The catalyst offers molecules a new route where less push energy (activation energy) is needed to start the reaction. Molecules dock on its surface, weaken their bonds, and transform into products faster.

History

The word 'catalysis' was proposed by Jöns Berzelius in 1836, observing the acceleration of reactions in the presence of certain substances.

How it works

The catalyst offers molecules a new route where less push energy (activation energy) is needed to start the reaction. Molecules dock on its surface, weaken their bonds, and transform into products faster.

History

The term 'catalysis' was introduced by Swedish chemist Jöns Jacob Berzelius in 1836 to describe reactions accelerated in the presence of substances that themselves do not change. In 1895, Wilhelm Ostwald gave a quantitative definition of a catalyst as a substance that accelerates a reaction but does not shift equilibrium. In the early 20th century, Paul Sabatier discovered hydrogenation on metallic nickel, for which he received the Nobel Prize. Fritz Haber and Carl Bosch developed catalytic synthesis of ammonia, revolutionizing agriculture. Further development of enzymatic catalysis is associated with the names of Michaelis, Menten, Briggs and Haldane. Today, catalysis permeates petrochemistry, energy, and environmental protection.

How it works

The catalyst provides an alternative reaction pathway with a lower activation energy. In heterogeneous catalysis, chemisorption plays a decisive role — the formation of chemical bonds between the reactants and the active sites on the surface. This weakens certain interatomic bonds in the reactant molecules, facilitating their breaking. Then the adsorbed particles interact, forming products that desorb, freeing the sites. For example, in ammonia synthesis on an iron catalyst, N₂ and H₂ molecules dissociate into atoms, which requires high energy without a catalyst. The reaction rate is often described by the Arrhenius equation: k = A exp(-Ea/RT), where Ea is the activation energy. The catalyst lowers Ea. In enzymes, an additional role is played by the complementarity of the active site to the substrate (lock-and-key model) and stabilization of the transition state.

Open problems & fun facts

Design of catalysts with predictable activity and selectivity without empirical trial and error.; Creation of stable and cheap catalysts based on common elements instead of platinum for fuel cells.; Understanding mechanisms of catalyst deactivation and development of regeneration methods.

💡 A zeolite catalyst (aluminosilicate) in oil cracking has a specific surface area of up to 1000 m²/g — in one teaspoon, the unfolded surface is comparable to a football field.