Synthesis and study of CuNiTiO3 as an ORR electrocatalyst to enhance microbial fuel cell efficiency

Microbial fuel cells (MFCs) have the capability of simultaneous sewage treatment and electricity generation. Modifying the cathode electrode enhances their efficiency. In this study, NiTiO3 and CuNiTiO3 were synthesized for practical application as cathode catalysts in a dual-chamber MFC and the performance of the modified cathodes was evaluated against a bare graphite electrode. SEM images showed that the particle sizes were mostly in the range of 40–120 and 20–80 nm for NiTiO3 and CuNiTiO3, respectively. According to AFM results, CuNiTiO3 presented a higher surface roughness than NiTiO3. MFC using CuNiTiO3/G electrode with a reduction potential value of −0.27 V (vs. SCE) and a power density of 62.18 mW m−2 showed better oxygen reduction reaction (ORR) activity compared with NiTiO3/G and the bare graphite. MFC using CuNiTiO3 cathode also showed the highest values in terms of chemical oxygen demand (COD) removal (75%) and the calculated coulombic efficiency (CE, 10%). The results obtained in this study, introduce CuNiTiO3 as a promising electrocatalyst for further improvement of the cathodic reactions in MFC applications.