Al-Modulated Zeolitic Acid–Metal Interactions Promote Selective Hydrodeoxygenation of Lignin-Derived Phenols to Cycloalkanes

Abstract

Catalytic hydrodeoxygenation of lignin-derived phenolics to jet-fuel-relevant cycloalkanes over non-noble metals requires balanced hydrogenation and deoxygenation functions. Here, a framework-Al-regulated Ni/ZSM-5 bifunctional catalyst was developed by tuning the Si/Al ratio to coordinately regulate zeolite acidity, Ni dispersion, and the acid–metal interface. The resulting interface couples H2 activation and aromatic hydrogenation on metallic Ni with C–O bond activation and cleavage on Al-derived Brønsted/Lewis acid sites. Under 230 °C and 3 MPa H2, 10Ni/ZSM-5-60 achieved >99.9% guaiacol conversion and >99.9% cycloalkane selectivity, with a TOF of 331.1 molguaiacol·mol Ni–1·h–1. The catalyst also showed broad applicability toward lignin-derived phenolics and model compounds. Enzymatic hydrolysis lignin oil was upgraded to 77.8% hydrocarbons, while oxygen content decreased from 27.0 to 5.2 wt % and calculated higher heating value increased from 27.3 to 45.1 MJ·kg–1. Framework-Al regulation thus provides an effective strategy for lignin upgrading toward sustainable aviation fuel precursors.