The pN-C was annealed in a 5% H2/95% N2 atmosphere at 200 ℃. 5.3 mg H2PtCl6 (38 wt.% Pt) were dissolved to 18 mL EG in a vial. In a separate vial, 0.1 g NaBH4 was quickly dissolved in water and this solution was poured into the solution containing the Pt salts as described above.