Fabrication of eco-friendly carbon microtubes @ nitrogen-doped reduced graphene oxide hybrid as an excellent carbonaceous scaffold to load MnO2 nanowall (PANI nanorod) as bifunctional material for high-performance supercapacitor and oxygen reduction reaction catalyst

Abstract Recently, with the concept of building a resource-conserving and environment-friendly society, the idea of developing green, sustainable and multifunctional materials has become increasingly urgent. So, how to explore more possible ways for efficient and sustainable utilization of biomass resources is very important. In this paper, a novel eco-friendly and sustainable 3D bifunctional carbon microtubes@nitrogen-doped reduced graphene oxide (CMT@N-RGO) hybrid based biomass material is firstly fabricated by combining dipping and chemical vapor deposition methods. Then the CMT@N-RGO hybrid is served as an excellent carbonaceous scaffold for constructing hierarchical hybrid with high-performance in energy storage and electrocatalysis. Finally, we have successfully prepared CMT@N-RGO/MnO2 and CMT@N-RGO/PANI hybrid with good supercapacitive and excellent oxygen reduction reaction (ORR). In short, the as-fabricated hybrid served as electrodes of supercapacitor present fast charge/discharge rate, excellent rate performance, and outstanding capacitance retention of 95% (93%) and high energy efficiency of 65–77% (61–72%) for both. In addition, the hybrid acted as an efficient electrocatalyst in the oxygen reduction reaction shows a larger positive onset potential of −0.12 V and half-wave potential of −0.21 V, which can be comparable to that of commercial Pt/C electrode. The improved capacitive and electrocatalytic properties are mainly attributed to the synergistic effects between the CMT and N-RGO/PANI (MnO2). In a word, these attractive results demonstrate that the 3D CMT@N-RGO/PANI (MnO2) hybrid are promising high-performance bifunctional material for supercapacitors and ORR catalyst. Hopefully, it can open up a versatile way for us to devise and manufacture more various multifunctional biomass-based material with outstanding electrochemical properties, excellent oxygen reduction reaction performance and other outstanding properties.