Porous Carbon Nanosheets Codoped with Nitrogen and Sulfur for Oxygen Reduction Reaction in Microbial Fuel Cells

Abstract

In this work, a simple synthesis strategy has been developed for the preparation of nitrogen- and sulfur-codoped porous carbon nanosheets (N/S-CNS) as a cathode catalyst for microbial fuel cells (MFCs). The as-prepared N/S-CNS showed favorable features for electrochemical energy conversion such as high surface area (1004 m(2) g(-1)), defect structure, and abundant exposure of active sites that arose primarily from porous nanosheet morphology. Benefiting from the unique nanostructure, the resulting nanosheets exhibited effective electrocatalytic activity toward oxygen reduction reaction (ORR). The onset potential of the N/S-CNS in linear-sweep voltammetry was approximately -0.05 V vs Ag/AgCl in neutral phosphate buffer saline. Electrochemical impedance spectroscopy showed that the ohmic and charge-transfer resistance of the codoped catalyst were 1.5 and 14.8 Ω, respectively, both of which were lower than that of platinum/carbon (Pt/C). Furthermore, the electron-transfer number of the N/S-CNS was calculated to be ∼3.5, suggesting that ORR on the catalyst proceeds predominantly through the favorable four-electron pathway. The MFC with N/S-CNS as a cathode catalyst generated current density (6.6 A m(-2)) comparable to that with Pt/C (7.3 A m(-2)). The high durability and low price indicate that N/S-CNS can be a competitive catalyst for applications of MFCs.

Nitrogen Doped Graphene as Potential Material for Hydrogen Storage

“…Herein nitrogen doped graphene shows a vertical uptake under P/P 0 = 0.04, and a hysteresis loop from P/P 0 = 0.5 to P/P 0 = 1.0 which is due to the co-existence of both micropores and mesopores. It can be seen that there are little ultramicropores in the nitrogen doped graphene material [68]. It is believed that the porous materials with a surface area would provide more active sites and thus improve the hydrogen storage capacity [69].…”

Chitosan Intercalated Metal Organic Gel as a Green Precursor of Fe Entrenched and Fe Distributed N-Doped Mesoporous Graphitic Carbon for Oxygen Reduction Reaction

“…The high resolution N 1s spectra show four different signals at binding energies of 398.55, 400.54, 401.64 and 404.73 eV corresponding to the pyridinic, pyrrolic, graphitic and pyridinic N−O bond respectively for CHI‐TMA−Fe‐CW (Figure a) and at 398.62, 401.31 and 403.95 eV corresponding to the pyridinic, graphitic and pyridinic N−O bond respectively for CHI‐TMA−Fe‐CW−M1(Figure b). The two main nitrogen species providing the active sites of ORR are the pyridinic and graphitic N .…”

Nanotechnology for Achieving Green-Economy Through Sustainable Energy

“…Use of nano principles and structures in energy sector helps achieve green economy by decreasing the usage of raw materials, by increasing the efficiency, life-cycle and stability of the cells,Most of the next-gensolar-powered batteries used for converting sun energy into mechanical, chemical, or electrical energy [85][86][87][88] are based on nanostructured materials like nanowires, mesoscopic nano-structures, quantum dot cells etc. 89,90 .One of major fascinating and supple conventional energy methods is the photovoltaic effect, directly converting solar energy to electrical energy and recent developments in the area of nanotechnology have opened new horizons for accelerating the electrical outputs of photovoltaic cells.…”