Nitrogen-doped activated graphene/SWCNT hybrid for oxygen reduction reaction

Pt-free catalyst towards oxygen reduction reaction (ORR) that is highly active, stable, and low-cost is highly desirable for commercialization of fuel cells but still remains unresolved. Here, we report a hybrid material of nitrogen-doped activated graphene/carbon nanotubes via a simple self-assembly of graphene and carbon nanotubes followed by KOH activation and high temperature annealing in NH3 for an efficient metal-free catalyst for ORR. The single-walled carbon nanotubes are well intercalated into nanoporous graphene layers, which lead to a high surface area and electrical conductivity of the hybrid. The nitrogen doping provides more reactive sites for ORR and significantly enhances the reaction properties. The hybrid structure exhibits excellent catalytic behavior with a four-electron pathway in alkaline media and better stability than the commercial Pt/C catalyst. This study opens a new direction for developing low-cost and highly efficient carbon-based ORR electrocatalysts.