Resumo

ORTEGA-CHAVEZ, Laura et al. Mathematical modeling of hydrogen evolution reaction in percloric and sulfuric acid solutions. Rev. Int. Contam. Ambient [online]. 2008, vol.24, n.1, pp.21-31. ISSN 0188-4999.

Fuel cells constitute at the present time, one of the main technologies that are object of continuous investigations in the search of alternative power sources with a minimum environmental impact. Nevertheless, the use of fuel cell technology has been limited by factors such as the high cost of the different components from which a fuel cell is constituted. One of such components is platinum, used because it is the best catalyst to carry out the electrochemical reaction between hydrogen and oxygen, responsible for the production of electrical energy. In the search of the optimization and/or substitution of platinum, it is important to count on a methodology that allows to make a diagnosis in situ of the state of the catalyst. This diagnosis involves aspects such as: the determination of the active sites, and loads and degradation that the catalyst can suffer during the operation of the cell. The present work consists of the development of a mathematical model that fed with the rate constants and the phenomena involved in hydrogen evolution reaction, produces like output data, the polarization curves (E vs I) and electrochemical impedance spectroscopy for this reaction. The monocrystalline Pt(111) and Pt(100) were considered like catalyst and diverse acids were used like electrolytes. The curves obtained with the mathematical algorithm show a correlation between the influence of the type and concentration of acids used like electrolytes and the current density due to the evolution of H₂. Finally, this model leaves an open possibility to explore the effect of different values involved in the reactions of a fuel cell, which will allow us to evaluate in situ the state and behavior of the catalyst.

Palavras-chave : fuel cells; catalyst; platinum; polarization curves; electrochemical impedance.