Biohydrogen evolution via ferric oxide-intercalated graphene oxide modified nickel foam biocathode in single-chamber...

The prohibitive cost of platinum-based cathodes remains a primary constraint on scaling microbial electrolysis cells (MECs) for renewable hydrogen (H₂) production. This work addresses this barrier by developing a high-performance, cost-efficient cathode composed of a Fe₃O₄-intercalated graphene oxide nanocomposite on 3D nickel foam (Fe₃O₄-GO@NF). The electrode exhibits hydrogen evolution reaction (HER) kinetics comparable to Pt/C, evidenced by a low Tafel slope (57.91 mV·dec^-1) and minimal charge-transfer resistance. In single-chamber MECs fed with sewage sludge, the Fe₃O₄-GO@NF cathode delivers a sustained H₂ production rate of 49.79 mL·L^-1·day^-1 and achieves a remarkable electrical energy efficiency (η_e) of 202 % at 0.9 V. Microbial community analysis, The next-generation sequencing (NGS) of the biofilm revealed a diverse microbial consortium dominated by polysaccharide-degrading taxa (Bacteroidetes phylum) and key exoelectrogens such as Geobacter species, indicating synergistic biocatalysis. This work establishes Fe₃O₄-GO@NF as a durable, non-precious catalyst that enables efficient H₂ generation from waste, providing a viable pathway for scalable bio-electrochemical energy systems.