S. Han, C. Zhou
Kansas State University,
Keywords: carbon nanotubes, graphene, microbial fuel cell, nano-biotech
Summary:An efficient highly conductive three-dimensional (3D) air-cathode manufactured by growth of carbon nanotubes (CNT s) on graphene sheets (GNS) for the improvement of H2O2-producing microbial fuel cell (MFC) is reported. 3D architectured GNS-CNT s hybrid as air-cathode allows for an enhanced production rates of H2O2 within its hierarchical porous structure. Correspondingly, the resulted GNS-CNT s hybrid showed adjustable electrochemical performance as an MFC air-cathode. 1.9 and 2.7 fold higher current density and H2O2 production rate normalized to total surface area were reached on GNS-CNT s hybrid air-cathode versus carbon air-cathode controls for the reduction of O2. Importantly, different electron transfer efficiencies on GNS-CNT s hybrid air-cathode result in different electric charge distributions, which affects its molecular spatial arrangement and three-dimensional conformation. The nanostructure enhances the air-cathode interaction and electron transfer rate. The CNTs produced the highest electrical conductivity (σ), whereas a high CNTs functionalization and the two-dimensional planar structure of GNS were promising for improving the thermal conductivity. A combination of CNTs and GNSs exploited the advantages of both. This work paves a feasible pathway to prepare carbon nanomaterials with favorable 3D architecture and high performance, for use in MFC and energy conversion. The use of the efficient carbon nanomaterial MFC leads to a highly conductive three-dimensional air-cathode for the improvement of bio-electrochemical H2O2 regeneration, making the nanomaterial an extremely efficient material from an engineering perspective as well.