A comparative study of hydrogen evolution on Pt/GC and Pt/GNPs in acid solution

We present a comparative study of the electrocatalytic performance of catalysts obtained by electrochemical and spontaneous deposition of Pt on glassy carbon (GC) and graphene nanoplatelets (GNPs) supports. Pt/GC, with high Pt loading, obtained by electrochemical deposition of Pt, and Pt/GNPs, with low Pt loading, obtained by spontaneous deposition, show the highest activity for the hydrogen evolution reaction (HER) in acid solution. AFM images of Pt/GC reveal that the GC coverage by Pt nanoparticles is 87%, while SEM images of Pt/GNPs do not show the presence of Pt species due to their small amount. XPS analysis confirms that the amount of Pt is 48.1 wt% in Pt/GC and 4.6 wt% in Pt/GNPs. The HER activity of both catalysts is equally high, showing onset potentials close to 0.0V (vs. RHE). The Tafel slopes of 30 mV/dec for Pt/GC and 37 mV/dec for Pt/GNPs indicate different HER mechanisms.