Surface nonuniformity and kinetic insensitivity on heterogeneous catalysts

A new model for single-route, steady-state reactions on nonuniform catalytic surfaces is presented. Giving up some assumptions of the Temkin model and making use of a common mean-value theorem result in the introduction of the concept of kinetic insensitivity. The model rigorously accounts for the existence of a broad class of reactions the evolution of which is accurately described by “classical kinetics” (derived on ideal, uniform surfaces). The connections with structure sensitivity/insensitivity are examined in relation with the frequently invoked effect of surface restructuring. The application to two-step sequences leads to the classical Temkin model (as a particular case) and reveals some of its shortcomings, not yet reported.