A novel and durable oxygen reduction reaction catalyst with enhanced bio-energy generation in microbial fuel cells based on Ag/Ag2WO4@f-MWCNTs

Abstract

• Ag/Ag 2 WO 4 @f-MWCNTs was fabricated with a scalable, high efficiency, energy-saving, and time-saving strategy. • Ag/Ag 2 WO 4 @f-MWCNTs catalyst enriches oxygen diffusion and facilitates oxygen reduction reaction in MFCs. • The Ag/Ag 2 WO 4 @f-MWCNTs catalyst indicates high cathodic oxygen reduction reaction rate with 4e – pathway. • The Ag/Ag 2 WO 4 @f-MWCNTs has the potential to be an alternative to Pt/C-based oxygen reduction reaction catalysts. • The usage of this catalyst can substantially improves power production and enables broader applications of MFCs. Microbial fuel cell, as a promising technology, utilizes microorganisms to break down and oxidize the organic matter for harvesting energy. Progress in creating specific compositional functionalities of electrodes that are catalytically active, durable, cost-effective, and energy-recovery efficient is exclusively challenging for microbial fuel cell operation because of its bio-compatibility requirement. The electrodes composition impresses the oxidation-reduction reaction and electron charge-discharge rates. This study explores the use of silver/silver tungstate supported on different kinds of carbon materials, as cathode material for microbial fuel cells. The as-prepared catalysts were synthesized by a simple, environment-friendly, and self-developed surfactant-less method. Among proposed catalysts, the Ag/Ag 2 WO 4 @f-MWCNTs upgraded the oxygen reduction reaction to a four-electron pathway. As well, the optimal catalyst Ag/Ag 2 WO 4 @f-MWCNTs, exhibited excellent oxygen reduction reaction performance activity and stability with onset potential of -0.037 V and kinetic current density of 17.66 mA cm −2 compared with other synthesized catalysts and even the standard Pt/C catalyst. Owing to the more active sites, larger surface, and faster charge transfer, the microbial fuel cell equipped Ag/Ag 2 WO 4 @f-MWCNTs device delivered a high power density and current density of 0.965 W m –2 and 6.43 A m –2 , respectively. Consequently, Ag/Ag 2 WO 4 @f-MWCNTs is an effective catalyst that has the potential to be an alternative to Pt/C-based oxygen reduction reaction catalysts. The usage of this Ag/Ag 2 WO 4 @f-MWCNTs catalyst can therefore substantially improves power production and enable broader applications of microbial fuel cells for renewable electricity generation using waste materials.