Facile Synthesis of Fe/N/S‐Doped Carbon Tubes as High‐Performance Cathode and Anode for Microbial Fuel Cells

Abstract

As a renewable energy technology, microbial fuel cell (MFC) has been attracting increasing attention in recent decades. However, practical applications of MFCs has been hampered by the unsatisfactory electrode performance, in particular, at the cathode. Herein, Fe/N/S-doped carbon hollow tubes were prepared by a facile two-stage procedure involving hydrothermal treatment and pyrolysis at controlled temperatures. Electrochemical studies showed that the obtained samples exhibited an apparent electrocatalytic activity towards oxygen reduction reaction in both alkaline and acidic media, a performance comparable to that of commercial Pt/C, and the sample prepared at 800°C stood out as the best among the series with a half-wave potential of + 0.81 V vs. RHE and an electron transfer number of 3.98 at + 0.6 V vs. RHE. The Fe/N/S-doped carbon tubes also exhibited a remarkable performance as an MFC anode by facilitating bacterial growth and electron transfer between the biofilm and electrode. In fact, an MFC based on the carbon tubes as both cathode and anode showed a markedly higher performance (maximum power density 479 W m À 3 ) than the control MFC based on a graphene aerogel anode and Pt/C cathode (359 W m À 3 ). These results suggest that Fe/N/S-doped carbon composites can be used for the fabrication of high-efficiency MFC electrodes.[a] Dr.

Facile Synthesis of Nitrogen/Sulfur Co-doped Three-Dimensional Holey Graphene Hydrogels for High Supercapacitive Performance

“…The peaks at 164.1 and 165.3 eV are assigned to the C–S–C species of S 2p3/2 and S 2p1/2 , respectively, which is ascribed to sulfur atoms in the graphene matrix. The peak at 168.9 eV is the characteristic peak of −SO x –(−C–SO 2 –C– or −C–SO 3 –C−), which is most likely derived from the sulfate ion doped in the process of GO synthesis from graphite . Incorporating S-atoms into the graphene matrix produced electrochemical active sites.…”

“…The peak at 168.9 eV is the characteristic peak of −SO x −(−C−SO 2 −C− or −C−SO 3 −C−), which is most likely derived from the sulfate ion doped in the process of GO synthesis from graphite. 28 Incorporating S-atoms into the graphene matrix produced electrochemical active sites. Also, the oxidized sulfur groups can provide pseudo-capacitance by a reversible redox reaction between −SO x and C−S−C.…”

Carbon‐Based Composites as Anodes for Microbial Fuel Cells: Recent Advances and Challenges

“…Similar with the carbides, FeS 2 can act as a extracellular and insoluble substrate for the electricity conducting microbes to breathe and grow well, resulting in an enhanced biocompatibility. [199,200] Also, during the reduction of bacteria by iron ions, the electron transport is mediated by S. [200,201] When covered by the FeS 2 , the affinity towards microorganisms and electrocatalytic activity were both promoted for the carbon cloth anode, leading to a facilitated electron transfer and higher electronic capacitance, thus delivering an outstanding power density of 1128 mW m À 2 . [176] Similar with Fe 3 O 4 , SrFe 12 O 19 as a magnetic material can induce the adhesion of microbes to form a dense biofilm consisting of numerous nanowires, which mediates the bacteria movement and facilitates the extracellular electron transfer.…”