Redox Sorption in Metal-Ion-Exchanger Nanocomposites upon Electrochemical Polarization

A conjugated macrokinetic problem is solved for two moving boundaries of chemical reactions during redox sorption in metal-ion-exchange nanocomposites under conditions of current flow. Numerical solutions to the multipoint boundary value problem indicate that the impact of the current includes a slowing of front migration associated with distinct stages of the chemical reaction between metal nanoparticles and oxygen due to electrochemical reduction, a reduced surface concentration of the active sorbate (oxygen), and an increased degree of redox sorption. An increase in the contribution from the electrochemical component and a transition to external diffusion control are observed as the current density grows.