Abstract

Graphene oxide improves electricity generation in soil microbial fuel cells and plant microbial fuel cells.

Author(s): Gary Charles

Graphene oxide (GO) was studied for its effects on electricity generation in soil microbial fuel cells (SMFCs) and plant microbial fuel cells (PMFCs). GO was added to soil at concentrations ranging from 0 to 1.9 gkg-1 and reduced for 10 days under anaerobic conditions. All SMFCs (GO-SMFCs) that used GO-incubated soils produced more electricity at a faster rate and in greater quantities than SMFCs that did not contain GO. The overall average electricity generation in GO-SMFCs containing 1.0 gkg-1 of GO was 40±19 mWm-2, which was significantly higher than the value of 6.6±8.9 mWm-2 generated by GO-free SMFCs in fed-batch operations (p<0.05). Cyclic voltammetry (CV) for GO-SMFC revealed an increase in catalytic current at the oxidative potential, with the CV curve indicating enhanced electron transfer from oxidation of organic substances in the soil by the reduced form of GO. The GO-containing PMFC also produced more electricity than the PMFC without any added GO, with the GO-PMFC producing 49 mWm-2 of electricity after 27 days of operation. This study shows that GO added to soil can be microbially reduced in soil and facilitates electron transfer to the anode in both SMFCs and PMFCs.