Enhanced H<sub>2</sub>-Rich Gas Production via Steam Reforming of Toluene over Ni-Based Hydrotalcite-Derived Catalysts at Low Temperature
Jie Ren, Feilong Yang, Yiling Liu
Abstract
Tar reforming in the presence of Ni-based catalysts is a promising method for syngas production during biomass gasification, but common Ni-based catalysts (e.g., Ni/Al2O3) are easily deactivated during actual operation. In this work, Mg–Al hydrotalcite was synthesized by coprecipitation, followed by Ni impregnation and calcination, to obtain a Ni/MgAl catalyst, which exhibited excellent activity and stability for toluene (as a tar model compound) conversion. After various types of characterization and experimental investigations, the reaction and deactivation pathways were explained. The optimized Ni/MgAl-10 catalyst with better Ni dispersion, tailored basicity, and specific surface area showed remarkable toluene conversion (98.5%) and H2 production (609 mmol/g-Ni) at a low temperature. On the basis of calculations of the apparent activation energy and turnover frequency (TOF), Ni/MgAl-10, with the lowest activation energy (25.6 kJ/mol) and highest TOF value (4.31 h–1), was found to be the most active catalyst for H2-rich gas production. Moreover, the spent catalyst was systemically characterized by SEM and XPS, and mechanisms of reaction and deactivation were proposed. This work developed a strategy for the design of an active and stable catalyst for toluene reforming, which has potential for application in the reforming of real tar during biomass gasification.