Collaborative Improvement Electrochemical Properties of Supercapacitor Electrodes by Loading MoS2 Nanosheets on Biomass Hierarchical Porous Carbon

MoS2, a typical two-dimensional transition metal sulfide nanomaterial, has attracted much attention for supercapacitor electrode materials due to its high theoretical capacity. Herein, MoS2 nanosheets growing on a hierarchical porous carbon (HPGC) derived from pomelo peel are prepared via hydrothermal method. The curled MoS2 nanosheets uniformly grow and distribute on the conductive hierarchical porous carbon matrix, which made the electrodes materials possess a high specific surface area (320.2 m2/g). Simultaneously, the novel structure enhances the conductivity of MoS2, alleviates capacity attenuation and guarantees the interface stability. Furthermore, the MoS2/HPGC show a great enhancement in supercapacitor performance and deliver a remarkable specific capacitance of 411.4 F/g at the current density of 0.5 A/g. The initial capacitance retention rate is approximately 94.3% after 2000 cycles. It turns out that the synergistic effects between the MoS2 nanosheets and HPGC contribute to high specific capacity, excellent rate performance and ultra-long cycle life. This work provides a new idea for the design and development of MoS2 composites as the electrode materials of supercapacitors.

Fabrication of Co, N-Doping Hierarchical Porous Graphene from Metal Organic Framework for Oxygen Reduction Reaction in Microbial Fuel Cell

Graphene is a very attractive 2D carbon material, while the synthesis route of functional graphene is complex and complicated. The purpose of this study is to develop Co/N co-doped grapheme catalyst for ORR.Herein, a facile and universal pyrolysis method to explore the preparation of Co-N co-doped graphene through thermal exfoliation of 3D Co0.5Zn0.5-ZIF metal-organic framework by dimension reduction, and study the specific changes during process of dimensionality reduction, aiming at contributing to the transformation mode of 3D materials into 2D materials. The results showed that LiCl and KCl play different roles, namely the building carbon layer, pore-creating and exfoliation and acted simultaneously when they are added. A unique ultrathin 2D morphology of Co/N co-doped graphene, pores formed with the volatilization of zinc ions, and the appearance of abundant Co-Nx active sites, which endow efficient catalytic activity of oxygen reduction reaction (ORR) in the alkaline electrolyte. Co/N-Go-Li/K-800 possesses the superior ORR activity among Co/N-Go-Li/K-T with an onset potential (0.15V vs Ag/AgCl) and higher limiting current density([email protected] vs. Ag/AgCl) (-5.20 mA•cm-2) closer to Pt/C (0.17V vs. Ag/AgCl and -5.86 mA•cm-2).