Low-Temperature Reforming of Biomass Tar over Ni/ZSM-5 Catalysts: Unraveling the H2-Rich Gas Production Pathways Using In Situ and Ex Situ Techniques

It is important to unravel the generation mechanism of H2-rich gas from biomass tar reforming, which is beneficial to advance the development of gasification technology. In the present work, Ni supported on ZSM-5 zeolites with different Si/Al ratios were employed for reforming of biomass tar and toluene (as a tar model compound). Among the obtained catalysts, Ni supported on ZSM-5 with a Si/Al ratio of 80 (Ni/Z80) exhibited the highest activity in biomass tar reforming at 650 °C, and the syngas yield reached up to 80.5 mmol/g when steam was introduced to the system. Moreover, outstanding catalytic performance was observed in toluene reforming over the Ni/Z80, and the toluene conversion reached 83.1% at 600 °C. With the help of advanced characterization techniques, the excellent physiochemical structure supported its superior behavior in the reforming. Through the in situ diffuse reflectance infrared Fourier transform spectroscopy, the reforming mechanism involved in the transformation of reaction intermediates was identified.