Abstract: The influence of the main catalyst ink preparation parameters, such as sonication dispersing time and dispersants, on the electrochemical performance of 50% Pt/C was studied and discussed. The sonication dispersion time and dispersants have obvious effects on the performance of Pt/C. The optimized sonication dispersion time is 10 min. In the case of sonication dispersion time less than 10 min, the performance is inferior because of the uncompleted dispersion of the electrocatalyst. While in the case of sonication dispersion time more than 10 min, the performance is also poor due to Pt particles agglomeration caused by the temperature increase in the catalyst ink during the sonication dispersion process. The dispersants also significantly affect the activity of Pt/C. When ethanol is adopted as the dispersant, Pt/C possesses a higher electrochemical surface area and exhibits the highest activity for oxygen reduction reaction. This could be attributed to the joint characteristics of low polarization and low viscosity of ethanol. Moreover, the lower temperature of the catalyst ink during the sonication dispersion process using ethanol as the dispersant also contributes to its desirable electrochemical results.

Key words: platinum, carbon supported catalyst, sonication dispersion, dispersant, electrocatalytic activity, oxygen reduction