CuO vs. AgO: A comparative study of cathode catalysts for boosting oxygen reduction in microbial desalination cells

Microbial Desalination Cell (MDC) is an innovative approach for water desalination that concurrently produces energy through the process of substrate oxidation. The primary issue of the technique is its limited power on capabilities during the oxygen reduction reaction (ORR). While the depletion of oxygen is a significant process in electrochemical energy conversion, its slow kinetics hinder its utilization in MDCs. One potential resolution to this problem is the utilization of a cathode catalyst with a high level of activity, which effectively enhances the rate of ORR. Different concentrations of copper oxide (CuO) nanoparticles (NPs) were used to investigate the behavior of ORR and its impact on the performance of the MDC. The optimal concentration of silver oxide (AgO) NPs was utilized to conduct a comparative analysis of both types of NPs. The size of CuO NPs and AgO NPs was found to be 65 nm and 55 nm respectively by material characterization studies. The power density achieved in the absence of the catalyst was 1.1 W/m3, and this value increased to 4.9 W/m3 with the incorporation of 3 mg/cm2 AgO. The use of a catalyst loading of 3 mg/cm2 has been determined to be efficacious in enhancing the desalination rate in MDC. The electrochemical investigations conducted also showed an improvement in the electrocatalytic behavior of cathodic kinetics while operating under these specific afterward. Therefore, the utilization of AgO catalyst exhibits potential as a viable option for the expansion of MDC processes, thereby contributing to the achievement of sustainable development objectives. [Display omitted] •AgO vs CuO -green and eco-friendly catalysts for enhancing the MDC performance.•Material characterization revealed that CuO and AgO NPs have a size of 65 and 55 nm.•Electrochemical analyses revealed boost in ORR and redox current with AgO over CuO.•COD & TDS removal of 86 % and 92 % showed bioremediation in MDC with 3 mg/cm2 of AgO.•AgO has potential to expand MDC for upscaling application & longevity in operation.