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 (LiNbO3), 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 LiNbO3 were studied with and without UV–vis irradiation to assess its photocatalytic behavior in these devices. The synthesized phase of LiNbO3 was characterized by X-ray diffraction, differential scanning calorimetry, particle size distribution, and transmission electron microscopy analyses. The MFC containing a LiNbO3-based cathode exhibited a maximum open circuit potential and power output of 400 mV and 131 mW/m3, 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 LiNbO3 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.