Microwave Assisted Hydrothermal Way Towards Highly Crystalized N-Doped Carbon Quantum Dots and Their Oxygen Reduction Performance

We proposed a green microwave-assisted hydrothermal way to synthesize highly crystalized N-doped carbon quantum dots(N-CQDs).The N-CQDs obtained by this microwave method have good crystalline degree(ID/IG=0.6)and a high molar ratio of N/C(11.1%)comparing with those obtained from traditional top-down method.The experimental results show that glycerine plays a key role ill the fonnation of highly crystalized N-CQDs.The as-prepared N-CQDs have good luminescent property and may be utilized as fluorescent probe to detect ions or mark cells.As the majority of N atoms in the N-CQDs were pyridinic type(64.8%),the as-prepared N-CQDs were used as a catalyst for the oxygen reduction reaction(ORR)electrocatalysis in the anode of the fuel cell(the onset potential is-0.121V),which was a 4e-transfer procedure and the catalyst showed good stability after 100 cycles.