SOME PROPERTY FEATURES OF NANOSTRUCTURED MATERIALS AS PARTICIPANTS OF CHEMICAL PROCESSES

Abstract

The article considers a number of features of thermodynamic regularities peculiar to nanostructured materials and the nature of the dependence of the activation energy of processes involving nanostructured materials on the effective particle size of the nanosubstance. Under these conditions, the effective particle size (a) or the number of elementary components of low-atom clusters (atoms, molecules, and radicals) becomes a thermodynamic parameter. In particular, the chemical potential of a substance in case of nanoscale particles is a function of their effective size, or more strictly, a function of the concentrations of vacancies in C_a. The value of C_a, in its turn, is determined by the value of a, the level of the surface energy, and the change in the volume of particles that results from the replacement of the atom by a vacancy in them. The activation energy of processes (E_A) in which nanoparticles participate (direct and reverse chemical reactions, adsorption and desorption phenomena as their varieties) become a function of the magnitude of nanostructured particles. A similar phenomenon is characteristic of adsorption centres’ energy activity of diverse nature. It leads to an increase in the role of fluctuations and random processes and to the appearance of a bifurcation point on the dependence E_A = f(a), from which various directions of the processes, leading to an apparent scatter of the experimental data, are possible. The observed picture, to a certain extent, is similar to the Heisenberg uncertainty principle. At the same time it has some significant differences.

ACKNOWLEDGEMENTS

The research was carried out at the expense of a grant from the Russian Science Foundation (project No. 18-16-00006).