Green Synthesis of Heteroatom Doped Graphene from Natural and Chemical Precursors for Oxygen Reduction Reaction

In the present work, natural biomass and chemical materials were applied as the heteroatom resources for modifying the Porous Graphene (PG) structure by pyrolysis method at ۹۰۰ ºC. The physical and chemical characterizatons were performed by means of Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), Raman Spectroscopy, N۲ Adsorption-Desorption, and X-ray Photo-electron Spectroscopy (XPS). Furthemore, the behavior of the prepared materials was investigated by Cyclic Voltammetry (CV) and Rotating Disk Electrode (RDE). The obtained results indicated that doping of heteroatoms into the graphene framework was possible using a low-cost and environment-friendly biomass material as well as chemical sources. Moreover, one-step quarternary and tersiary co-doped graphene could be acheived using natural biomass. The prepared electrocatalysts using grape leaves and sulfur trioxide pyridine complex exhibit higher electrocatalytic performance as exampled which conducted the electrocatalyst in ۴e- pathway and showed high stability in methanol solutions during the process, confirming their considerable potential to Oxygen Reduction Reaction (ORR) as an electro-catalyst. Moreover, the onset potential of Gl۳۰۰G-۹۰۰ and GSP ۹۰۰ (۰.۹۳ V vs RHE) is almost equal to the Pt/C ۲۰ wt % (۰.۹۹ V vs RHE). These optimal prepared cathodes (Gl۳۰۰G-۹۰۰ and GSP ۹۰۰) in the Microbial Fuel Cell (MFC) test lead to considerable power densities of ۳۱.۵ mW m-۲ and ۳۰.۹.mW m-۲, which are close to ۳۸.۶ mW m-۲ for the Pt/C ۲۰ wt % cathode.

Keywords:

Alkaline fuel cell , Fuel Cell , graphene , Electrocatalyst , Natural resources