Increasing the biohydrogen production efficiency through the dark fermentation process has become the biggest challenge in recent years. We aim to enhance biohydrogen production yield by adding nano-sized iron oxide doped metal oxides prepared by the wet impregnation method. Biohydrogen production in the presence of additives was evaluated by the screening of (i) type (Fe2O3@Al2O3, Fe2O3@ZrO2, and Fe2O3@TiO2) and (ii) concentration (0-200 mg/L) of additives. During the screening of additive type, approximately 14 wt% nano-sized (6 nm) hematite (Fe2O3) doped Al2O3 showed the highest improvement for biohydrogen production yield among all additives. Batch experiments conducted through dark fermentation demonstrated that 50 mg/L Fe2O3@Al2O3 addition caused an acceleration in biohydrogen production by 34% and an increment in yield by 15%, despite even low concentrations Al2O3 addition inhibited the process. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.