Influence of calcination temperature on the evolution of α-MoO3 nanosheets catalyst for aqueous phase reforming of biogas slurry

Abstract

Renewable hydrogen sources from organic wastewater, which is increasingly recognized as one of the key strategies to achieve carbon peaking and carbon neutrality goals under the new development philosophy. Meanwhile, the treatment of biogas slurry (BS) has a serious impact on the environment, hindering the application of anaerobic digestion. In this study, a novel method that combined aqueous phase reforming (APR) over α-MoO3 nanosheets and activated carbon adsorption was presented, considering sustainable management and conservation of resources. This study examined the relationships between catalyst calcination temperature and catalytic performance of α-MoO3 nanosheets in the APR of BS. A series of catalysts synthesized by thermally hydrogenating and calcined from 400 to 700 °C were characterized and evaluated. Results indicated that hydrogen yield increased at first and then decreased with the increment of calcination temperature due to the change of van der Waals (vdW) heterostructures. The shrinkage of vdW heterostructures of α-MoO3 nanosheets can contribute to the generation of hydrogen because of the low oxygen vacancies and surface acidic property. As a result, the optimal removal efficiencies of the pollutants (non-purgeable organic carbon (NPOC), chemical oxygen demand (COD), total nitrogen (TN), and ammonia nitrogen (AN)) reached 79.45%, 87.82%, 49.78%, and 50.22%, respectively. The optimal hydrogen yield (4.91 mLHydrogen/mLBS) was also achieved using α-MoO3 nanosheets calcined at 600 °C. This work can provide an effective strategy to treat and utilize organic wastewater.