Ferric oxide/carbon nanoparticles enhanced bio-hydrogen production from glucose

Hydrogen (H2) gas represents renewable resource candidate to traditional energy resource. Methods to promote the H2 evolution rate attract increasing attentions. In the present research, ferric oxide/carbon nanoparticles (FOCNPs) were synthesized and evaluated the feasibility to enhance the production rate of H2 gas from glucose through anaerobic fermentation by mixed bacteria. The results demonstrated that appropriate dose of FOCNPs promoted, while excessive concentration of FOCNPs suppressed the production of H2. Addition of 200 mg/L FOCNPs resulted in the highest yield of 218.63 ml H2/g glucose, 33.7% higher than 163 ml H2/g glucose of the control test without addition of FOCNPs. However, 400 mg/L of FOCNPs inhibited the H2 evolution to 154 ml/g glucose, 5.5% lower than the control. It was revealed that the H2 evolution followed the acetic pathways. The FOCNPs had a specific surface area of 27.63 m2/g, and thus addition of FOCNPs could provide more attachment sites for the growth of anaerobes. Moreover, FOCNPs could promote the activity of hydrogenase and electron transfer efficiency, beneficial for the bio-H2 evolution. However, excessive addition of FOCNPs could be toxic to microbes, and further suppressing the H2 production. The present research provided an effective method to promote the evolution rate of H2 gas.