Enhanced bio-hydrogen production by photo-fermentation of corn stalk using Fe-doped CaTiO3 photocatalyst

The aim of this study was to analyze the effects of CaTiO 3 photocatalysts doped with different concentrations of Fe on the biohydrogen production process by photo-fermentation using corn stover as the substrate. The experimental results showed that the maximum cumulative hydrogen production and the maximum rate of hydrogen production were obtained when the doping concentration was 6 % (g/g) (380.8 mL, 26.4 mL/h), which were 63.4 % and 203.4 % higher, respectively, than those of the blank control group (233 mL, 8.7 mL/h). The substrate conversion rate was 32.82 %. Iron-doped CaTiO 3 lowered the oxygen reduction potential in the fermentation system to provide a suitable reduction environment for the growth and fermentation of photosynthetic bacteria . The lowest redox potential observed was −393.5 mV for 6 % iron-doped CaTiO 3 . Thermogram analysis revealed a strong correlation between cumulative hydrogen production and redox potential. Additionally, the analysis of soluble small molecules showed that iron-doped CaTiO 3 could inhibit the production of ethanol from glycolysis during fermentation and promote the utilization of small molecule acids.