Fabrication and electrochemical properties of well-dispersed molybdenum oxide nanoparticles into nitrogen-doped ordered mesoporous carbons for supercapacitors

Abstract

Environment-friendly supercapacitors demand the high-performance electrode materials working with neutral aqueous electrolyte. In this work, the nitrogen-doped ordered mesoporous carbons (NOMCs) have been synthesized and subsequently modified with molybdenum oxide nanoparticles (NPs) by a self-developed temperature controlled impregnation method. The prepared hybrids possess ordered mesoporous structure, high specific surface area (600–1000 m2 g−1), favorable pore size (∼4 nm) and well-dispersed uniform molybdenum oxide NPs. The results demonstrate that the nano-sized molybdenum oxides encapsulated in the ordered mesoporous channels exhibit significant electrochemical activity with an enhanced specific capacitance up to 410 F g−1, which can be attributed to the nanosize effects from the nanopore confinement and efficient surface area of molybdenum oxide NPs under well dispersion. The hybrids exhibit quasi-rectangular CV curves within the enlarged potential window compared with the pristine NOMCs together with pairs of redox peaks owing to the multi-valance changes of molybdenum corresponding to the Faradaic reactions. Thus, the synthesized hybrids demonstrate not only the synergistic contribution of electrical double-layer capacitance and pseudocapacitance but also superior cycling stability in aqueous neutral electrolyte.