Display omitted •Co-fermentation of residual algal biomass and glucose under the influence of Fe3O4 NPs.•Fe3O4 NPs leads ∼ 37.14 % higher cumulative H2 as compared to control at 37 °C.•∼ 11.28 % higher hydrogen production at optimum temperature in presence of Fe3O4 NPs.•Evaluates hydrogen production at different pH in presence of Fe3O4 NPs.•Potential of nanomaterials induced enhanced hydrogen production using co-fermentation. The present study reports Fe3O4 nanoparticles (Fe3O4 NPs) induced enhanced hydrogen production via co-fermentation of glucose and residual algal biomass (cyanobacteria Lyngbya limnetica). A significant enhancement of dark fermentative H2 production has been noticed under the influence of co-fermentation of glucose and residual algal biomass using Fe3O4 NPs as catalyst. Further, using the optimized ratio of glucose to residual algal biomass (10:4), ∼ 37.14 % higher cumulative H2 has been recorded in presence of 7.5 mg/L Fe3O4 NPs as compared to control at 37 °C. In addition, under the optimum conditions glucose to residual algal biomass ratio (10:4) presence of 7.5 mg/L Fe3O4 NPs produces ∼ 937 mL/L cumulative H2 in 168 h at pH 7.5 and at temperature 40 °C. Clostridum butyrium, employed for the dark fermentation yielded ∼ 7.7 g/L dry biomass in 168 h whereas acetate (9.0 g/L) and butyrate (6.2 g/L) have been recorded as the dominating metabolites.