Chemical Etching of TiO_2 Nanorods Greatly Improves Current Generation of S. Ioihica PV-4 on a Carbon Paper Electrode

摘要

Anode surface plays important role for extracellular electron transfer (EET) of exoelectrogenic microbes in microbial fuel cell (MFC). In this report, the electrochemical performance of a TiO_2 nanorod array modified carbon paper electrode (TiO_2 NRs/CP) is greatly improved by controlled chemical etching process. The etching process keeps the array morphology but yields obvious hollows on tops of TiO_2 nanorods. The etched electrode (TiO_2 NRs-HOT/CP) exhibits better hydrophilicity than carbon paper (CP) and TiO_2 NRs/CP electrode as seen from smaller contact angle (CA) and more attached microbes S.loihica PV-4. Meanwhile, the hollows allow higher local concentration of microbial self-secreted flavins that can act as electron mediators for interfacial electron transfer of PV-4 through in-direct pathway. Accordingly, PV-4 produces larger current density at TiO_2 NRs-HOT/CP electrode with maximum current density of 0.038 mA cm~(-2), which was much higher than that at CP electrode, and almost five times higher than that at un-etched TiO_2 NRs/CP electrode.