What are the steps involved in the Langmuir-Hinshelwood mechanism?
The Langmuir-Hinshelwood mechanism involves three main steps: (1) adsorption of reactants onto the catalyst surface, (2) reaction between adsorbed species, and (3) desorption of products from the catalyst surface.
How does the Langmuir-Hinshelwood mechanism differ from the Eley-Rideal mechanism?
The Langmuir-Hinshelwood mechanism involves the reaction of two adsorbed reactants on a catalyst's surface, while the Eley-Rideal mechanism involves a reaction between one adsorbed reactant and one reactant directly from the gas phase.
What assumptions are made in the Langmuir-Hinshelwood mechanism?
The Langmuir-Hinshelwood mechanism assumes that adsorption of reactants occurs on a uniform catalyst surface, surface adsorption is in equilibrium, the surface reaction is the rate-determining step, and adsorbed species do not interact. Additionally, it assumes that only a monolayer of adsorbates covers the surface and that the desorption step is rapid.
What types of reactions typically follow the Langmuir-Hinshelwood mechanism?
Heterogeneous catalytic reactions, particularly surface reactions such as hydrogenations, oxidations, and ammonia synthesis, typically follow the Langmuir-Hinshelwood mechanism. This involves the adsorption of reactants on a catalyst surface, the surface reaction between adsorbed species, and subsequent desorption of the products.
What factors influence the rate of reaction in the Langmuir-Hinshelwood mechanism?
The rate of reaction in the Langmuir-Hinshelwood mechanism is influenced by the surface coverage of reactants, adsorption and desorption constants, temperature, and the catalytic surface's activity. These factors affect how reactants adsorb onto, react on, and desorb from the catalytic surface.