Construction of efficient bioelectrochemical devices: Improved electricity production from cyanobacteria (Leptolyngbia sp.) based on pi-conjugated conducting polymer/gold nanoparticle composite interfaces

Abstract

In this study, gold electrodes (GE) were coated with conducting polymers to obtain a high photocurrent using cyanobacteria from a novel bioelectrochemical fuel cell. For this purpose, 4-(4H-ditiheno{[}3,2-b:2',3'-d]pyrol-4-yl) aniline and 5-(4H-dithieno{[}3,2-b:2',3'-d]pyrol-4-yl) napthtalane-1-amine monomers were coated on GE by performing an electropolymerization process. After that, gold nanoparticles (AuNP) were specifically modified by 2-mercaptoethane sulfonic acid and p-aminothiophenol to attach to the electrode surface. The conducting polymers GE coat was modified with functionalized AuNP using a cross-linker. The resulting electrode structures were characterized by cyclic voltammetry and chronoamperometry under on-off illumination using a fiber optic light source. Cyanobacteria Leptolyngbia sp. was added to the GE/conducting polymer/AuNP electrode surface and stabilized by using a cellulose membrane. During the illumination, water was oxidized by the photosynthesis, and oxygen was released. The released oxygen was electrocatalytically reduced at the cathode surface and a 25 nA/cm(2) photocurrent was observed in GE/Leptolyngbia sp. After the electrode modifications, a significant improvement in the photocurrent up to 630 nA/cm(2) was achieved.