The catalytic effect of TiO2 nanosheets on extracellular electron transfer of Shewanella loihica PV-4. Issue 43 (19th October 2016)

• Record Type: Journal Article
• Authors: Yin, Tao; Li, Hui; Su, Lin; Liu, Shuo; Yuan, Chunwei; Fu, Degang
• Is Part Of: Physical chemistry chemical physics. Volume 18:Issue 43(2016)
• Page Start: 29871
• Page End: 29878
• Publication Date: 2016-10-19
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c6cp04509j
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : TiO2 nanosheets accelerate the extracellular electron transfer rate of Shewanella loihica PV-4. Abstract : Electron transfer kinetics of Shewanella loihica PV-4 at the up-growing TiO2 nanosheet (TiO2 -NS) modified carbon paper (CP) electrode was investigated. The effect of TiO2 -NSs, which speeds up the interfacial electron transfer of outer membrane c -type cytochromes (OMCs), was revealed for the first time. TiO2 -NSs with a polar surface modified hydrophobic CP into super-hydrophilic TiO2 -NS/CP. The favorable interaction between PV-4 and TiO2 -NSs not only enhanced microbial adhesion, but also altered the redox nature of OMCs. The mid-point potential of OMCs at TiO2 -NS/CP was shifted to a more negative potential, indicating a higher thermodynamic driving force for the protein to release electrons. Moreover, electron transfer from OMCs to TiO2 -NSs was also benefited from the positive shift of flat-band potential V fb owing to reduced pH at the electrode/microorganism interface, as well as good electrical conductivity of TiO2 -NSs. As a result, the electron transfer rate constant k et of OMCs at the TiO2 -NS/CP anode was about three times faster than that at the CP anode. The accelerated electron transfer kinetics as well as 15% increase of biomass together accounted for a 97% increase of the maximum output power density in the MFC. The result expanded our knowledge about the role of a designed TiO2 nanostructure in microbial electron transfer that can be applied in other bio-electrochemical systems.