Investigation of Nitrogen-Doping Influence on the Electrocatalytic Activity of Graphene in Alkaline Oxygen Reduction Reaction

Abstract

Fuel cell is considered an energetic solution of low environmental impact which large-scale commercialization is hindered by the expensive Pt-based cathodic electrocatalyst. Therefore, its replacement by an active less-expensive metal-free electrocatalyst such as nitrogen-doped graphene (N-graphene) is desirable. To investigate nitrogen-doping influence on graphene's activity in alkaline oxygen reduction reaction (ORR), we prepared N-graphene through thermal treatment of graphene and urea at 800 °C for 30 min. N-graphene exhibited higher onset potential, half-wave potential, diffusion-limited current density and kinetic current density in ORR (0.78 V vs RHE, 0.63 V vs RHE, -3.36 mA cm -2 , -3.00 mA cm -2 , respectively) than undoped graphene (0.73 V vs RHE, 0.62 V vs RHE, -2.80 mA cm -2 , -2.23 mA cm -2 , respectively), which may be attributed to nitrogen-doping, edges and defect sites in N-graphene, as revealed by elemental analysis, scanning electron microscopy and Raman spectroscopy results. This activity improvement also affected ORR's selectivity and ratedetermining step.

Recent Developments in Carbon-Based Nanocomposites for Fuel Cell Applications: A Review

“…As a result, fuel cells are one of the most appealing technologies for addressing global energy and environmental concerns while also making our lives cleaner and more sustainable. An electrolyte is layered between two electrodes in an atypical fuel cell [80]. On the anode surface, the fuel is oxidized, and the liberated electrons pass through an external circuit to decrease O 2 at the cathode.…”