Sulfur-doped graphitic carbon nitride decorated with graphene quantum dots for an efficient metal-free electrocatalyst

A rationally designed strategy has been developed for spontaneous reduction and assembly of graphene quantum dots rich in carbonyl and carboxylic groups (ox-GQDs) onto sulfur doped graphitic carbon nitride (s-g-C₃N₄) nanosheets to form unique s-g-C₃N₄@GQD nanohybrids by a one-step hydrothermal treatment. The fabricated architectures exhibit remarkably enhanced catalytic activity in the oxygen reduction reaction far better than the original s-g-C₃N₄ and GQDs, which is even comparable to those of well-developed graphene and GQD-based catalysts, demonstrating the potential towards energy conversion applications.