Facile and economic synthesis of heteroatoms co-doped graphene using garlic biomass as a highly stable electrocatalyst toward 4 e− ORR

In this work, garlic-derived graphene as an economic biomass material was used for preparation of quaternary (S, N, P and B)-doped carbon via pyrolysis at 900 °C for 2 h under nitrogen atmosphere. The as-synthesized electrocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray photo-electron spectroscopy. Moreover, electrochemical evaluation was performed by rotating disk electrode and cyclic voltammetry techniques. The obtained results showed that inserting of four heteroatoms to graphene framework is possible using a low-cost and environment friendly biomass material. The prepared electrocatalyst shows good selectivity to 4e − pathway in alkaline oxygen reduction reaction as well as excellent resistance toward methanol crossover effects, confirming their considerable potential to oxygen reduction reaction as an electro-catalyst. Moreover, the onset potential of heteroatoms-doped graphene using garlic (S300G900) sample (0.90 vs. RHE) is very close to Pt/C 20 wt% (0.99 V vs. RHE).