Recently, with the concept of building a resource-saving and environment-friendly society, the idea of developing green, sustainable and multifunctional materials has become more and more urgent. Therefore, how to explore more possible ways to effectively and sustainably use biomass resources is very important. In this paper, a new type of environmentally friendly and sustainable 3D bifunctional carbon microtube@nitrogen-doped reduced graphene oxide (CMT@N-RGO) hybrid material was first prepared by a combination of impregnation and chemical vapor deposition. Then, the CMT@N-RGO hybrid was used as an excellent carbon scaffold to construct a hierarchical hybrid with high performance in energy storage and electrocatalysis. Finally, we successfully prepared CMT@N-RGO/MnO2 and CMT@N-RGO/PANI hybrids with good supercapacitance and excellent oxygen reduction reaction (ORR). In short, hybrid batteries have fast charge/discharge rates, excellent rate performance, excellent capacitance retention rate of 95% (93%) and high energy efficiency of 65-77% (61-72%). In addition, the hybrid, which is an effective electrocatalyst in the oxygen reduction reaction, shows a larger positive onset potential of 0.12 V and a half-wave potential of 0.21 V, which can be compared with commercial Pt/C electrodes. The improved capacitance and electrocatalytic performance are mainly attributed to the synergy between CMT and NRGO/PANI (MnO2). These attractive results indicate that 3D CMT@N-RGO/PANI (MnO2) impurities are expected to become high-performance dual-functional materials for supercapacitors and ORR catalysts. I hope it can open up a general way for us to design and manufacture more multifunctional biomass-based materials with excellent electrochemical performance, excellent oxygen reduction reaction performance and other excellent performance.




Figure 1. SEM images of (a, b) CMT and (c, d) CMT@N-RGO at different magnifications. (D) The illustration is the EDS of CMT@NRGO.




Figure 2. CV curve of CMT@N-RGO under different (a) scan rate and (b) voltage window. (C) GCD curves of hybrids at various current densities. (D) Nyquist plots of CMT and CMT@N-RGO.




Figure 3. SEM images of (a,b) CMT@N-RGO/MnO2 nanowall and (c,d) CMT@N-RGO/PANI nanorods at different magnifications. The illustrations shown in (b,d) are the EDS of CMT@N-RGO/MnO2 nanowall and CMT@N-RGO/PANI.




Figure 4. (a) CV curve, (b) GCD curve, (c) capacitance retention rate and (d) specific capacitance of CMT@NRGO/MnO2 and CMT@N-RGO/PANI at different scan rates and current densities Compared with energy efficiency.





Figure 5. Oxygen reduction reaction characteristics of CMT@N-RGO/PANI hybrid (a) CV curve tested in N2 and O2 saturated KOH solution (0.1 M). (B) Comparison of the polarization curves of Pt/C, CMT and CMT@N-RGO/PANI. (C) Polarization curves of CMT@N-RGO/PANI at different speeds.


Relevant research results were published in the Journal of Power Sources, 2020, 447, 227387 by the Chuanyin Xiong group of Shaanxi University of Science and Technology in 2020. Original: 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.