The Interaction between Electricigens and Carbon Nanotube Forest and Electricity Generation Performance in MFC

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.