Synthesis of Tungstate Oxide/Bismuth Tungstate Composite and Application in Microbial Fuel Cell as Superior Low-Cost Cathode Catalyst than Platinum

Low cost tungsten oxide/bismuth tungstate (WO 3 /Bi 2 WO 6 ) composite was synthesized and used as cathode catalyst in microbial fuel cell (MFC). Almost 1.5 times increment in specific surface area of WO 3 /Bi 2 WO 6 composite was observed as compared with WO 3 and WO 3 /Bi 2 WO 6 exhibited efficient oxygen reduction reaction (ORR) having a current peak of 8.1 mA at – 12.6 mV during cyclic voltammetry analysis, demonstrating less ORR overpotential. The MFC using WO 3 /Bi 2 WO 6 catalysed cathode could recover a power density (PD) of 145 ± 4.5 mW/m 2 and coulombic efficiency (CE) of 28.3 ± 1.5%, followed by 35 ± 5.8 mW/m 2 and 17.5 ± 2.4%, respectively, for MFC with WO 3 catalyzed cathode and 10.4 ± 3.2 mW/m 2 and 10.3 ± 0.9%, respectively, for MFC without any cathode catalyst. Moreover, the PD and CE of 138 ± 6.8 mW/m 2 and 27.5 ± 2.0%, respectively, obtained from MFC using Pt/C cathode catalyst, was slightly lower than the MFC with WO 3 /Bi 2 WO 6 catalyst on cathode. The specific power recovery per unit cost of cathode fabrication of 23.8 mW/$ obtained from MFC with WO 3 /Bi 2 WO 6 catalyzed cathode is higher than the MFC with Pt/C (12.2 mW/$), making it low cost alternative for scaling-up of MFCs.