Molten-Salt-Mediated Synthesis Of Carbon-Based Materials For Microbial Fuel Cells

Microbial fuel cells?Microbial Fuel Cells,MFCs?are very attractive bio-electrochemical systems that are capable of directly converting the chemical energy stored in organic wastes into electrical energy with the aid of microorganisms.Significant efforts have been devoted to MFCs due to their potentials in wastewater treatment with simultaneous electricity generation.However,relatively low power density and high capital costs are critical limiting factors for its scaling up applications.The electrocatalysis for oxygen reduction reaction of cathode as well as the dynamic activity of anode are key factors determining the power generation and waste treatment efficiency in MFCs.To solve these problems we carried out the following work:?1?We herein report a molten-salt-mediated method to prepare a cost-effective Fe-containing N-doped carbon?denoted as Fe/C/Ns-900?as ORR electrocatalyst.Systematic characterization via a variety of techniques,demonstrates the Fe/C/Ns-900holds a porous structure and has large surface areas.The Fe/C/Ns-900 was studied as an electrocatalyst for ORR and showed excellent activity in neutral electrolyte,exhibited an onset potential close to 0.81 V?vs.RHE?and the current density reach at5.8 mA cm^-2,inspiring us to establish a MFC using the cost-effective Fe/C/Ns-900 as cathode catalyst.The optimum MFC device showed a maximum power density of 900±5 mW m^-2,outperforming the MFC made using the Pt/C as cathode catalyst.?2?In this study,peanut shell is proposed as a novel electrode material prepared via a simple carbonization procedure with molten-salt?C-s-800?.The C-s-800 was demonstrated to possess three dimensional?3D?hierarchical porous structures,high conductivity and eco-friendly properties.The C-s-800exhibited an onset potential close to 0.82 V?vs.RHE?and the current density reach at 6.3 mA cm^-2.As cathode catalyst,the C-s-800 generates a power density of 1560 mW m^-2,around 1.2 times higher than that in Pt/C(1300 mW m^-2).As anode catalyst,the C-s-800 also process promising performance that achieved a maximum power density(1740 mW m^-2)3.2 times higher than carbon cloth anode.Additionally,the C-s-800 was investigated by operating as both the anode and the cathode of MFC and achieved a maximum power density(904mW m^-2).