Several factors contribute to non-linear relationships in catalysis:
1. Reaction Mechanisms: Many catalytic reactions involve multiple steps, and the overall reaction rate is often governed by the slowest step, known as the rate-determining step. The presence of multiple intermediates and transition states can lead to non-linear kinetics.
2. Surface Phenomena: The surface of a catalyst can exhibit non-linear behavior due to adsorption and desorption dynamics, surface diffusion, and active site availability. For instance, the adsorption of reactants might follow a Langmuir isotherm, which is inherently non-linear.
3. Temperature and Pressure Effects: Changes in temperature and pressure can affect reaction rates and equilibria in a non-linear manner. For example, increasing temperature might exponentially increase the rate of an endothermic reaction due to the Arrhenius equation.
