5 g of melamine was heated in a semi-closed crucible at 550 °C for 2 h at a heating rate of 10 °C min−1 in a muffle furnace. Then, cooled to room temperature naturally. A yellow colored g-C3N4 powder was obtained. The as-synthesized g-C3N4 was subsequently used to synthesize the PtAu/gC3N4 hybrid