Abstract
An activated carbon fiber felt (ACFF) cathode lacking metal catalysts is used in an upflow microbial fuel cell (UMFC). The maximum power density with the ACFF cathode is 315 mW m−2 , compared to lower values with cathodes made of plain carbon paper (67 mW m−2 ), carbon felt (77 mW m−2 ), or platinum-coated carbon paper (124 mW m−2, 0.2 mg-Pt cm−2 ). The addition of platinum to the ACFF cathode (0.2 mg-Pt cm−2 ) increases the maximum power density to 391 mW m−2 . Power production is further increased to 784 mW m−2 by increasing the cathode surface area and shaping it into a tubular form. With ACFF cutting into granules, the maximum power is 481 mW m−2 (0.5 cm granules), and 667 mW m−2 (1.0 cm granules). These results show that ACFF cathodes lacking metal catalysts can be used to substantially increase power production in UMFC compared to traditional materials lacking a precious metal catalyst.