Synthesis and physicochemical characterization of hierarchical ZSM-5: Effect of organosilanes on the catalyst properties and performance in the catalytic fast pyrolysis of biomass

Abstract

Abstract Two series of ZSM-5 catalysts with hierarchical porosity were hydrothermally synthesized by adding two types of organosilane reagents (OSA) into the medial synthesis system. The effects of the types and addition amounts of OSA on the pore characteristics, crystallinity, morphology and acidity of the ZSM-5 zeolites were studied by XRD, SEM, TEM, N2-adsorption, 27Al MAS NMR and NH3-TPD. Mesopores were generated by introducing appropriate amounts of OSA. In addition, the catalytic performance of the hierarchical ZSM-5s were investigated for the catalytic fast pyrolysis (CFP) of cellulose. The increase in the mesoporosity leads to a reduced amount of coke. However, the highest yield of aromatics was obtained for the mesoporous sample with the greatest microporosity. Thus, the right balance between meso- and microporosity is critical for achieving high aromatic yields. In addition, the distribution of aromatic products is directly related to the microporosity.