Modeling of hydrogen release during electrolysis of alkaline solution

Abstract

Electrochemical processes of electrolysis of solutions belong to heterogeneous processes, their most intensive development and flow occurs at the interface, namely at the contact line between the metal electrode and the liquid electrolyte. The paper describes an algorithm for solving the objective of calculating hydrogen evolution during electrolysis of alkaline electrolyte in one-dimensional approximation. This numerical algorithm makes it possible to predict the hydrogen yield, to find the rates of constants in electrode processes, as well as we calculate the concentrations of substances involved in electrode processes and their spatial distribution. The algorithm consists of two blocks. The first block is an independent objective to find rate constants of processes. Kinetic objectives make it possible to find rate constants of near-electrode processes and to estimate contributions of near-electrode processes. The second block is the solution of initial-boundary and boundary value objectives in the “one-dimensional” approximation. The difference schemes for solving these objectives are constructed by the integrointerpolation method on a uniform grid, and an explicit difference scheme is used for solving the initial-boundary objectives of the charged particle balance. Calculation of the amount of separated gas showed good convergence both at the cathode (hydrogen) and at the anode (oxygen). The calculation of the spatial ones showed characteristic gradients, i.e., rather qualitative convergence.