Carboxylic Carbon Nanotube: Catalyst Support Material and Oxygen Reduction Reaction of Microbial Fuel Cells

The catalyst support materials (CSMs) greatly affect the catalytic efficiency and performances of microbial fuel cells (MFCs). The purpose of this study is to evaluate the effect of prepared CSMs on oxygen reduction reaction (ORR) at the air cathode of MFCs. Membrane free single-chamber air cathode MFCs, M80 and M95, are constructed using carboxylic modified carbon nanotube (CNTs) prepared under different conditions as the CSMs. The Experimental results show that comparing with MPT (the control) containing Pt/C as catalyst, which gains a maximum power density of 447.29mW/m(2), the M80 achieves a maximum power density of 773.9 mW/m(2), Noticeably, the M95 increases the power density to 911.3 mW/m(2). Moreover, the internal resistance is decreased by 67% to 310 Omega of M95 and 44% to 359 Omega of M80 comparing with MPT(518 Omega). Besides, From the polarization curves, open circuit voltages are 0.735V and 0.776V for M80 and M95 which is higher than MPT with 0.621V. X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscope analysis demonstrate that the higher efficiency of Pt/CNT-2 catalyst may be attributable to the richer O, N and S-containing groups on the surface of CSM CNT-2 under higher temperature treatment.