Heteroatom doped mesoporous carbon/graphene nanosheets as highly efficient electrocatalysts for oxygen reduction

• Heteroatom doped mesoporous carbon/graphene (HMCG) were fabricated by nano-casting technology.
• In HMCGs, graphene is sandwiched in two heteroatom-doped mesoporous carbon layers.
• HMCGs exhibited excellent electrochemical performance for the oxygen reduction reaction.

The high cost of platinum (Pt) based catalysts for oxygen reduction reaction (ORR) has restricted the widespread commercialization of fuel cells. Heteroatom (N, B, P, S or Se) doped carbon materials have been regarded as the promising metal-free catalysts for replacing Pt based catalysts owing to their high efficiencies, good stability and relative low cost. In this work, we present a cost-effective synthesis approach for heteroatom (N and S) doped mesoporous carbon/graphene (HMCG) nanosheets by using nano-casting technology with mesoporous silica/graphene nanosheets (MSG) as hard templates, and four different amino acids (alanine, serine, arginine and cystine) as heteroatom (N, S) and carbon precursors. The resulting catalysts exhibited excellent electrocatalytic activity for ORR in alkaline media. In particular, HMCGAla with alanine as precursors showed the highest electron transfer numbers and durability. These results indicated the attractive potential of HMCGs as metal-free catalysts in practical fuel cells.

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