Influence of KOH-activated graphite nanofibers on the electrochemical behavior of Pt–Ru nanoparticle catalysts for fuel cells

Graphite nanofibers (GNFs) were activated chemically by a heat treatment at between 700 and 1000 °C. The GNFs were used as carbon supports for Pt–Ru nanoparticles in fuel cells. The surface, structural, and textural characteristics of the carbon supports and Pt–Ru/KOH-activated GNFs catalysts were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and surface area analyzer, respectively. The electrochemical activity was examined by cyclic voltammetry. The results showed that the concentration of oxygen functional groups and the specific surface area of the carbon supports increased with increasing activation temperature up to 900 °C, whereas the mean Pt–Ru nanoparticle size decreased due to an improvement in the dispersibility of the Pt–Ru/KOH-activated GNFs catalysts. From the results, it was found that the electrochemical activities of the Pt–Ru/KOH-activated GNFs catalysts were improved by the larger active surface area available due to an increase in the number of oxygen functional groups and specific surface area, resulting in the enhanced electrochemical activity for use in fuel cells.

Graphical AbstractThis is described that the CV data of the Pt–Ru/KOH-activated GNFs catalysts in 0.5 M H2SO4 containing 1.0 M CH3OH. This means the electrochemical activity increased with increasing chemical activation temperature up to K900-GNFs, and then decreased. Figure optionsDownload as PowerPoint slideHighlights
► GNFs were activated chemically by KOH with a heat treatment.
► Chemical activation increased the available active surface of GNFs.
► It is due to the lower Pt–Ru particle size, higher SSA and oxygen functional groups.
► Thus, the Pt–Ru/K900-GNFs catalyst showed the highest electrochemical activity.