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  2. Chemisorption - Wikipedia

    en.wikipedia.org/wiki/Chemisorption

    Chemisorption is a kind of adsorption which involves a chemical reaction between the surface and the adsorbate. New chemical bonds are generated at the adsorbent surface. Examples include macroscopic phenomena that can be very obvious, like corrosion [clarification needed], and subtler effects associated with heterogeneous catalysis, where the catalyst and reactants are in different pha

  3. Langmuir adsorption model - Wikipedia

    en.wikipedia.org/wiki/Langmuir_adsorption_model

    [2] Langmuir published two papers that confirmed the assumption that adsorbed films do not exceed one molecule in thickness. The first experiment involved observing electron emission from heated filaments in gases. [3] The second, a more direct evidence, examined and measured the films of liquid onto an adsorbent surface layer.

  4. Heterogeneous catalysis - Wikipedia

    en.wikipedia.org/wiki/Heterogeneous_catalysis

    Typical energies for physisorption are from 3 to 10 kcal/mol. [2] In heterogeneous catalysis, when a reactant molecule physisorbs to a catalyst, it is commonly said to be in a precursor state, an intermediate energy state before chemisorption, a more strongly bound adsorption. [6]

  5. Adsorption - Wikipedia

    en.wikipedia.org/wiki/Adsorption

    Adsorption is the adhesion [1] of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. [2] This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid (the absorbate) is dissolved by or permeates a liquid or solid (the absorbent). [3]

  6. Dissociative adsorption - Wikipedia

    en.wikipedia.org/wiki/Dissociative_adsorption

    The Langmuir model of adsorption [2] assumes . The maximum coverage is one adsorbate molecule per substrate site. Independent and equivalent adsorption sites. This model is the simplest useful approximation that still retains the dependence of the adsorption rate on the coverage, and in the simplest case, precursor states are not considered.

  7. BET theory - Wikipedia

    en.wikipedia.org/wiki/BET_theory

    BET model of multilayer adsorption, that is, a random distribution of sites covered by one, two, three, etc., adsorbate molecules. The concept of the theory is an extension of the Langmuir theory, which is a theory for monolayer molecular adsorption, to multilayer adsorption with the following hypotheses:

  8. Equimolar counterdiffusion - Wikipedia

    en.wikipedia.org/wiki/Equimolar_counterdiffusion

    In this process, the net molar flow rate of the mixture and the molar-average velocity are equal to zero, and mass transfer occurs by diffusion only without any convection taking place. The mole fraction, the molar concentration, and the partial pressure of both gases involved in equimolar counterdiffusion vary linearly. These relationships can ...

  9. Lindemann mechanism - Wikipedia

    en.wikipedia.org/wiki/Lindemann_mechanism

    This reaction was studied by Farrington Daniels and coworkers, and initially assumed to be a true unimolecular reaction. However it is now known to be a multistep reaction whose mechanism was established by Ogg [10] as: N 2 O 5 ⇌ NO 2 + NO 3 NO 2 + NO 3 → NO 2 + O 2 + NO NO + N 2 O 5 → 3 NO 2