In Situ Upgrading of Cellulose Pyrolysis Volatiles Using Hydrofluorinated and Platinum-Loaded HZSM-5 for High Selectivity Production of Light Aromatics

Abstract

The ZSM-5(Z5) was synergistically modified by leaching agent HF (0.5 mol/L) and metallic Pt (0.1, 0.2, 0.5, and 1 wt %) to prepare the bifunctional hierarchical Pt-FZ5 for enhancing light aromatic products by catalytic reforming of volatiles from cellulose pyrolysis. The results show that HF reduced the acidity and significantly increased the mesopores through the original pore enlargement, promoting uniform dispersion of metal Pt (outer and inner channels) and mass transfer of reactants with products. In addition, the metal Pt was mainly combined with Brønsted acid sites which promoted the cleavage of initial volatiles to produce more light aromatics rather than coke deposition. The Pt-FZ5 exhibited the highest aromatic yield of 30.3% with a high aromatic selectivity in bio-oil of 80.5% when the Pt loading is 0.2 wt % owing to its rich mesoporous (2–9 nm) and appropriate acidity. Meanwhile, the coke deposition of Pt-FZ5 was significantly inhibited.