On the use of ferroelectric material LiNbO3 as novel photocatalyst in wastewater-fed microbial fuel cells

Abstract In this work, the use of lithium niobate (LiNbO 3 ), a ferroelectric and photocatalyst material, is investigated as a new type of cathode catalyst for wastewater-fed single-chamber microbial fuel cells (MFCs). Carbon cloth electrodes coated with LiNbO 3 were studied with and without UV–vis irradiation to assess its photocatalytic behavior in these devices. The synthesized phase of LiNbO 3 was characterized by X-ray diffraction, differential scanning calorimetry, particle size distribution, and transmission electron microscopy analyses. The MFC containing a LiNbO 3 -based cathode exhibited a maximum open circuit potential and power output of 400 mV and 131 mW/m 3 , respectively, under irradiation. This cathode configuration also achieved the maximum chemical oxygen demand removal of 84% after 120 h of MFC operation. These results show that ferroelectric materials such as LiNbO 3 could be used as cathode catalysts in MFC devices. As a complementary analysis, the removal of the heavy metals detected in the wastewater was also monitored.