Enhanced Activated Carbon Cathode Performance for Microbial Fuel Cell by Blending Carbon Black

Abstract

Activated carbon (AC) is a useful and environmentally sustainable catalyst for oxygen reduction in air-cathode microbial fuel cells (MFCs), but there is great interest in improving its performance and longevity. To enhance the performance of AC cathodes, carbon black (CB) was added into AC at CB:AC ratios of 0, 2, 5, 10, and 15 wt % to increase electrical conductivity and facilitate electron transfer. AC cathodes were then evaluated in both MFCs and electrochemical cells and compared to reactors with cathodes made with Pt. Maximum power densities of MFCs were increased by 9-16% with CB compared to the plain AC in the first week. The optimal CB:AC ratio was 10% based on both MFC polarization tests and three electrode electrochemical tests. The maximum power density of the 10% CB cathode was initially 1560 ± 40 mW/m(2) and decreased by only 7% after 5 months of operation compared to a 61% decrease for the control (Pt catalyst, 570 ± 30 mW/m(2) after 5 months). The catalytic activities of Pt and AC (plain or with 10% CB) were further examined in rotating disk electrode (RDE) tests that minimized mass transfer limitations. The RDE tests showed that the limiting current of the AC with 10% CB was improved by up to 21% primarily due to a decrease in charge transfer resistance (25%). These results show that blending CB in AC is a simple and effective strategy to enhance AC cathode performance in MFCs and that further improvement in performance could be obtained by reducing mass transfer limitations.

Effect of varying the amount of binder on the electrochemical characteristics of palm shell activated carbon

“…Fluorinecontaining resin materials such as polytetrafluoroethylene (PTFE) are widely used as a binder, as they have excellent chemical and thermal resistance and are best known for their binding properties. PTFE is widely used as a binder for the fabrication of cathode for energy storage, particularly in microbial fuel cell [13][14][15][16] and capacitor/supercapacitor [17,18]. On one hand, Zarei, et al [19] developed carbon nanotube-PTFE cathode for dye removal under several different operating conditions, while on the other hand, Park, et al [20] prepared activated carbon-PTFE electrode sheet for desalination.…”

High Performance Platinum Group Metal-Free Cathode Catalysts for Microbial Fuel Cell (MFC)

“…In fact, it has been shown that i) surface chemistry, 22 ii) temperature treatment, 19,25 iii) pressure applied, 19 iv) AC loading, 22 v) content of binder (e.g. PTFE), 22 vi) addition of carbon black, 26 affect the cathode performances and the MFC output significantly. AC seems to be the cheapest and efficient solution to adopt for scaling up MFCs.…”

Effect of Operating Parameters on the Performance Evaluation of Benthic Microbial Fuel Cells Using Sediments from the Bay of Campeche, Mexico

“…After that, 12.6 µL of PTFE (Sigma-Aldrich, Cd Mexico, Mexico) to 60% and 233.3 µL of deionized water were added to the vial, followed by a 5 min ultrasound to form a paste. This paste was placed on the SSME as shown in Figure 1b [31]. The support was constructed with PVC as shown in Figure 1 where (c) serves as the base for the structure of the electrode, (d) is placed on top, then the Nafion ® membrane and electrode are placed so that the AC-CB face is on the membrane, then the electrode is pressed by placing (e) and finally the system is closed with (f).…”

“…Therefore, this performance has been limited mainly by the oxygen reduction reaction at the aqueous cathode due to the poor kinetics of the reaction at neutral pH, which is why some authors propose the use of aerated cathodes for BMFC, where the oxygen flow is 3.7 times higher than in an aqueous cathode [10,16,23,[28][29][30]. These air cathodes are composed of three layers: the first is the collector in which electrons are received from the anode through the external circuit, the second is the catalyst which promotes the reduction reaction at the cathode and the third layer is the diffuser, which allows the reaction, improving the conditions of evaporation and substrate consumption [18,31].…”