Fabrication Of Heteroatom-Doped Graphene Composites And Their Application As The Cathodic Catalysts In Fuel Cells

Direct methanol fuel cells( DMFCs) can directly convert chemical energy into electrical energy with a high conversion efficiency, high power density, and easy operation,which are considered to be a promising green energy generation technology. Catalysts for oxygen reduction reaction(ORR) on the cathode are the critical pivot in direct methanol fuel cells. However, the disadvantages of the cathodic Pt catalyst, including sluggish kinetics,poor tolerance to crossover and low stability, as well as limited reserves, hinder the further commercialization and market demands of direct methanol fuel cells. In this work, we utilize a one-step pyrolysis method to thermally synthesize two non-precious heteroatom-doped graphene denoted Co-NG and PSNG as low-cost and highly efficient catalyst for the oxygen reduction reaction(ORR). The synthesized complexes were characterized by transmission electron microscopy(TEM), X-ray diffraction(XRD),Raman spectroscopy, SEM energy-dispersive X-ray(EDX) and X-ray photoelectron spectroscopy( XPS). The electrocatalytic activity of the two kind of composite towards the ORR was evaluated using linear sweep voltammetry method. Electrochemical measurements reveal that the obtained two kind of composite has excellent catalytic activity towards the ORR in an alkaline electrolyte, including a large kinetic-limiting current density and good stability, as well as they exhibits the desirable four-electron pathway for the formation of water. These superior properties make the two kind of composite promising cathode catalyst for alkaline direct methanol fuel cells.