Exploring the potential of metal-doped perovskite-oxides as oxygen reduction catalyst for enhancing the performance of microbial desalination cells

Microbial desalination cells (MDCs) have been employed for dissolved salts and contaminant removal along with electricity production. Although oxygen depletion is a momentous reaction in the electrochemical energy transformation, its sluggish kinetics prevent it from being accustomed to fuel cells. Oxygen reduction reactions (ORR) in alkaline environments and perovskite oxide catalysts for converting energy electrochemically have emerged as excellent and promising alternatives. Various concentration of Sn-doped oxygen-deficient BaTiO3 was incorporated to study ORR behavior and effect on MDC performance. This perovskite catalyst contains a considerable percentage of cubic BaTiO3 (with 100 nm size) confirmed by material characterization studies. Power density obtained in the absence of the catalyst was 4.7 W/m3 which increased to 6.7 W/m3 upon utilization of BaTiO3 with salt removal of 76.7%. Catalyst loading of 1 mg/cm2 and initial total dissolved solid (TDS) concentration of 20 g/L was found to be effective for improving the desalination rate in MDC. Electrochemical analyses also revealed enhancement in electrocatalytic behavior of cathodic kinetics under such operating conditions. Thus, Sn-doped BaTiO3 catalyst can be a suitable candidate for upscaling of MDC to meet the sustainable development goals.