• Novel iron-streptomycin derived catalyst for ORR in MFCs fed with urine. • The half-wave potential results of Fe-STR show a better kinetic towards ORR. • Fe-STR-based cathodes allow MFCs to reach a power output 74% higher than AC. • The maximum power density output was 104.5 ± 0.0 μW cm−2 by using Fe-STR-cathodes. • MFC performance was stable for 3 months working with Fe-STR-based cathodes.