Platinum nanoparticles wrapped in carbon-dot-films as oxygen reduction reaction catalysts prepared by solution plasma sputtering

Fuel cells have become increasingly important in recent years because of their high energy efficiency and low environmental impact. However, key challenges remain in the widespread adoption of fuel-cell vehicles, including reducing Pt usage in catalysts and improving their durability. In this study, a high-performance Pt@carbon-dot-film core-shell catalyst was successfully synthesized using a nonequilibrium reaction field, <i>i.e.</i>, solution plasma (SP) process, by adjusting the electrolyte pH. Four pH solutions (pH = 4.4, 7, 8, and 11) were employed as the discharge liquid environment for the SP process. The catalyst synthesized in the pH = 8 solution exhibited a mass activity of approximately 500 mA mg^-1, which was twice as high as that of the commercial Pt/C catalyst (256 mA mg^-1) with the same loading amount. The onset and half-wave potentials were 0.99 and 0.89 V, respectively, both of which exceeded those of commercial Pt/C catalysts (0.95 and 0.86 V, respectively). Furthermore, the enhanced catalytic performance corresponded to the Pt/C bonding between Pt and the carbon shell generated during the SP process.