Two-electron oxygen reduction on fullerene C₆₀-carbon nanotubes covalent hybrid as a metal-free electrocatalyst

Nanocarbon materials are considered to be active for electrochemical oxygen reduction reaction (ORR) for hydrogen peroxide (H₂O₂) synthesis. In the present work, a new type of fullerene 60 (C₆₀)-carbon nanotubes (CNTs) hybrid with covalently attached C₆₀ onto outer surface of CNTs was synthesized. The structure of C₆₀-CNT hybrid was confirmed by physical and chemical characterizations and its conformation is proposed featuring the covalent incorporation of CNTs and C₆₀ derivative. C₆₀-CNT hybrid showed high efficiencies on electro-generating H₂O₂, owing to huge surface area and intermolecular electron-transfer in the hybrid structure. A high H₂O₂ production rate of 4834.57 mg L⁻¹ h⁻¹ (426.58 mmol L⁻¹) was achieved at − 0.2 V vs saturated calomel electrode (SCE).