The influence of deposited potential on the ORR activity of Pt catalysts on glassy carbon electrode

Abstract

In this study, Pt catalysts were fabricated on a glassy carbon (GC) electrode Pt/GC using a potentiostatic technique at different reduction potentials in potassium hexachloroplatinate solutions with hydrochloric acid. The compositions of the catalysts were determined using energy dispersive spectroscopy (EDS), the surface morphologies were observed using scanning electron microscopy (SEM), and the crystal structure was confirmed using thin-film X-ray diffraction (XRD). The results show that all the electrodeposited Pt/GC catalysts exhibit a higher electrochemical activity for the oxygen reduction reaction (ORR) when compared with a commercial Pt/C electrode. There is an optimum electrodeposited potential (-0.15 V vs. Ag/AgCl) at which the Pt/GC electrode displays the highest electrochemical activity for the ORR due to the high-index plane and shape effect of the Pt particles. At a lower electrodeposited potential, the applied current density is high enough to form large and coarse metal particles, while at a higher electrodeposited potential, the active sites of Pt particles decrease because of its equiaxed shape.