Enhancing oxygen reduction reaction in acidic medium: A novel electrocatalyst of Pt–Co embedded in nitrogen-rich carbon nanosheets derived from polypyrrole-g-C3N4

In this study, PtCo alloy nanoparticles (NPs) were successfully synthesized and deposited on nitrogen-rich carbon nanosheets derived from Polypyrrole-g-C 3 N 4 using a chemical reduction method. This electrocatalyst not only offers enhanced catalytic efficiency but also significantly improves the stability for the oxygen reduction reaction (ORR) in in acidic medium. In terms of electrocatalytic performance, the PtCo/CN@PPY-g-C 3 N 4 catalyst demonstrated a mass activity of 0.378 mA µg Pt −1 at 0.85 V, 0.131 mA µg Pt −1 at 0.9 V and a specific activity of 2.900 mA cm Pt −2 at 0.85 V, 1.004 mA cm Pt −2 at 0.9 V which are respectively 2.3, 2.8 and 10, 12 times higher than those of a commercial 20% Pt/C catalyst (0.166 mA µg Pt −1 at 0.85 V, 0.046 mA µg Pt −1 at 0.9 V and 0.285 mA cm Pt −2 at 0.85 V, 0.079 mA cm Pt −2 at 0.9 V). This indicates superior catalytic activity. Furthermore, after 5000 cycles, the PtCo/CN@PPY-g-C 3 N 4 retained approximately 77% at 0.85 V and 83% at 0.9 V of its initial mass activity, with only a 14 mV decrease in the half-wave potential, whereas commercial 20% Pt/C catalyst retained only 40% at0.85 V and 30% at 0.9 V of its initial mass activity. These enhancements can be attributed to the synergistic effects and strong interactions between the Pt–Co alloy nanoparticles and the carbon nitride support. The findings of this study underscore the potential of PtCo/CN@PPY-g-C 3 N 4 as a viable and efficient alternative to traditional catalysts in electrochemical applications.