Synthesis and characterization of PtNx/C as methanol-tolerant oxygen reduction electrocatalysts for a direct methanol fuel cell

Platinum nitride supported on carbon (PtNx/C) is synthesized by the novel strategy of chelating the Pt precursor followed by pyrolysis and is characterized as a possible cathode electrocatalyst for direct methanol fuel cells (DMFCs). The prepared PtNx/C is shown to possess high methanol tolerance and catalytic activity for the oxygen reduction reaction (ORR). The results indicate that the temperature of the heat treatment and the molar ratio of Pt to N in the precursor solution play important roles in the catalytic performance. A sample of PtNx/C prepared at 700 °C with a Pt:N ratio of 1:2 shows a significant decrease in the potential loss associated with the mixed potential and the poisoning effect by adsorbed methanol, and this results in a high power density of 180 mW cm−2. The performance is 30% higher than that of Pt/C under 4 M of methanol concentration.