Activation energy (E_a) of tribochemical and heterogeneous catalytic reactions

To better understand specific mechanisms of tribochemistry, related triboemisssion and catalytic effects should also be considered. The relationship between E_a and enthalpy (ΔH) with a catalyst is of particular importance because the energy required to go into transition state decreases, thereby decreasing the energy required to initiate the reaction. The mechanism of heterogeneous catalysis, however, is still under discussion. The same is due to tribochemistry and/or tribocatalysis. It is usually assumed that heterogeneous solid catalysts decrease activation energy, reflected as apparent activation energy (E_app). This work aims at providing existing literature evidence for the model presented in [1]. The reviewed data is consistent with the required anisotropy of angular distribution of exoelectrons emitted from perturbed surfaces, in particular from metal-insulator-metal thin film sandwich structures. Device and methods are designed for evaluating in a high-vacuum tribometer [2] the angular distribution of electrons triboemitted from solid catalyst materials.