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Carbon nanotube forest (CNTFs) is grown vertically on the surface of highly conductive mesophase pitch carbon fibers (Pitch‐CFs) in the chemical vapor deposition method. Then the CNTFs‐modified CFs (CNTFs‐Pitch‐CF) as an anode material is assembled into the single chamber microbial fuel cells (MFCs). Interaction between electricigens and carbon nanotubes (CNTs) is investigated. The toxicity of the CNTs can make electricigens expend energy or electrons to produce exopolysaccharid (EPS) as much as possible. Accordingly, this leads to low voltage and the long start up time for the CNTFs‐Pitch‐CF anode in the early period. When the activity of electricigens with the EPS reaches a stable state over time, the output voltage rises rapidly and the maximum power density of the CNTFs‐Pitch‐CF‐equiped MFC is increased to 1112 mW/m2, which is approximately 1.55‐fold higher than Pitch‐CF‐equiped MFC. And the CNTFs‐Pitch‐CF‐equiped MFC can keep high electricity generation performance of MFCs for a long time, which is 75 % larger than the Pitch‐CF‐equiped MFC. This method of the CNTFs modifying the CFs provides a new idea for increasing the electricity generation performance of the MFCs. Mechanism analysis The schematic is used to explain the interaction between the carbon nanotubes(CNTs) and electricigens. CNTs can stimulate the epidermis of elctricigens and cause biological response, making electricigens expend energy or electrons to produce exopolysaccharid (EPS). When EPS is sufficient to counteract the stimulation or toxicity of CNTs, the rough surface and forest structure of CNTs modified anode can greatly decrease the internal resistance and promote the extracellular electron transfer. [ABSTRACT FROM AUTHOR]

As a kind of nitrogen-containing material, polyamide acid (PAA) was doped by Fe using ferric trichloride (FeCl 3 ), thus obtaining a carbon material (Fe-PAA) containing iron and nitrogen. The preparation efficiency of this material as electrocatalyst was improved and the cost was reduced. In this study, Fe-PAA was used as cathode electrocatalyst in microbial fuel cells (MFCs), and the effect of holding time (HT) on the oxygen reduction was investigated. The oxygen reduction reaction (ORR) electron transfer number of the Fe-PAA was about 3.55 when the HT was 90 min. This result demonstrates that Fe-PAA could be a promising highly efficient and low-cost cathode catalyst which could be further applied in MFC expansion. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI)/reduced graphene oxide (rGO) were synthesized by in-situ polymerization and were decorated on mesophase pitch-based carbon fiber brush (Pitch-CB) anode to promote microbial fuel cells (MFCs) power production. Mesophase pitch-based carbon fiber brush (Pitch-CB) becomes one of the most important research objects in MFCs. The mesophase pitch-based carbon fiber (CF) has excellent conductivity (about 2.0 μΩ m) compared with PAN-based CF (about 30 μΩ m). But the high conductive CF's surfaces have strong inert, and they are relatively smooth, which make it difficult to be adhered and enriched by microbes. By applying the PANI/rGO composite anode, the maximum power density (MPD) was increased to 862 mW m −2 , which was approximately 1.21 times higher than that of the Pitch-CB. The PANI can improve the surface roughness and surface potential of CFs, thus enhancing the adhesion of microbes and electrogenic performance of MFC. After the rGO was doped, the electrogenic performance of MFC was further improved. This study introduces a promising modifying method for the fabrication of high-performance anodes from simple, environment-friendly materials. [ABSTRACT FROM AUTHOR]