catalystsubstrate

Catalystsubstrate is not a widely used standardized term in chemistry, but it refers to the interaction between a catalyst and the substrate involved in a chemical transformation. In most scholarly contexts, the more common phrasing is catalyst–substrate interaction or catalyst–substrate complex. The nature of this interaction influences reaction rate, selectivity, and mechanism, while the catalyst itself is typically not consumed.

In heterogeneous catalysis, the substrate adsorbs to a solid catalyst surface, forming a catalyst–substrate complex at active sites. Adsorption can be physical or chemical, and the surface then facilitates bond making and breaking. The products desorb, freeing the site for subsequent turnover. Mechanistic models include Langmuir–Hinshelwood, where both substrate and co-adsorbed species react on the surface, and Eley–Rideal, where gas-phase reactants react with adsorbed species.

In homogeneous catalysis, the substrate binds to a soluble catalyst, often forming a metal–substrate or organocatalyst–substrate complex. Binding mode and electronic properties influence activation energies and selectivity. The catalytic cycle proceeds through a sequence of intermediates, with the turnover frequency determined by the rate-determining step of the cycle.

In biocatalysis, enzymes provide highly specific active sites that form enzyme–substrate complexes. This binding orients substrates precisely and stabilizes transition states, yielding high rates and selectivity under mild conditions. Although the exact term catalystsubstrate is uncommon, the concept of a productive catalyst–substrate interaction underpins both chemical and biological catalysis.