5. Kinetic equations for heterogeneous catalysis reactions

For a succession of elementary steps in the catalytic cycle, with the kinetically limiting step known, the kinetic equation for the reaction r = f(P _i ) is established (with r reaction rate and P _i partial pressures of active ingredients i). Comparison with experimental results obtained in the absence of diffusional limitations (chemical regime) enables the mechanism to be validated if known, or the most likely mechanism(s) to be determined. However, reference to homogeneous catalysis mechanisms and direct or indirect characterization of chemisorbed intermediates often enable us to propose one (or more) reaction mechanism(s).