Sustainable hydrogen production in microbial electrolysis cell employing a Bifunctional NiFe2O4 nanocatalyst with acoustic assistance and life cycle assessment

This study investigates the bifunctional catalytic behavior of nickel ferrite (NiFe2O4) nanoparticles in microbial electrolysis cells (MECs) and incorporates a life cycle assessment (LCA) to evaluate their environmental impact. NiFe2O4 nanoparticles synthesized via hydrothermal methods were characterized using XRD, SEM, and FTIR, and used as both anode and cathode modifiers to enhance biohydrogen generation. Their redox-active surface improved biofilm formation and electron transfer on the anode while suppressing microbial fouling on the cathode. Manilkara zapota fruit waste served as a low-cost substrate, and ultrasonic acoustic studies determined the optimal slurry properties for microbial activity. The LCA compared MECs with and without nickel ferrite catalysts across four impact categories—global warming, acidification, eutrophication, and ozone depletion potentials. Results revealed that NiFe₂O₄-modified MECs significantly reduced electricity-related emissions by lowering external voltage demand, resulting in improved environmental sustainability. The coupling of catalyst optimization, substrate valorization, and life cycle evaluation demonstrates a comprehensive route toward energy-efficient and eco-friendly hydrogen production from biowaste.