Aqueous-Phase Reforming of Biogas Slurry over MOF-Derived α-MoO₃ Catalyst for Producing Renewable Hydrogen: Effect of Fermenting Time

Abstract

Aqueous-phase reforming (APR) is an alternative method for treating and utilizing biogas slurry (BS) to produce renewable hydrogen from organic oxygen-containing wastewater. Considering the fluctuating characteristics of BS with changes in the degree of fermentation, developing an efficient catalyst is a major concern for the APR of BS. The novel catalyst based on molybdenum-based metal–organic-framework-derived oxides (Mo-MOF-derived α-MoO3) was reported in this study. The results indicated that the variables (e.g., pH, organic load, and salinity) of BS corresponded to the fermentation times and exhibited decreasing trends after APR under the reaction conditions of 225 °C and 30 min. Decarboxylation was identified as the main side reaction in the APR of BS over the catalyst. An optimal yield of 2.17 mLhydrogen/mLBS was achieved when BS was obtained from 6 days of fermentation. Finally, the Mo-MOF-derived α-MoO3 catalyst was obtained from the greater specific surface area of MOFs. The catalyst had a weaker acidity than the initial α-MoO3, making it more preferred for facilitating the APR of BS.

Keywords

• aqueous-phase reforming
• MOF derivatives
• biogas slurry
• hydrogen
• wastewater treatment