A Mathematical Model for Her Reaction to Determine Different Pt loads onPt/C Electrodes

摘要

In the preparation of electrodes Pt / C, one of the highlights is its characterization, particularly the possibility of determining the effective charge of platinum available to carry out a reaction by a nondestructive technique. Electrochemical impedance spectroscopy (EIS) is a technique that provides high precision measurements, producing a stable response without significantly altering the system under study. This paper proposes the use of a hydrogen evolution reaction (HER) mathematical model, validated by experimental data obtained from the implementation of the EIS technique to electrodes with different Platinum loads, in a wide range of frequencies and five different overpotentials. The model takes into account the kinetic, diffusive and adsorption aspects, and also allows to obtain the rate constants for each step of the HER reaction in each of the electrodes used. Although this methodology was used only for Pt/C electrodes suggests a much broader application that extends to any metal electrodes that are capable of evolving hydrogen, with minimal modifications for each par-ticular case.