An efficient zeolite‐supported nickel‐iron bimetallic heterogeneous catalyst for hydrodeoxygenation of vanillin: A lignin model compound

Abstract

The selective hydrodeoxygenation (HDO) of lignin‐derived oxygenated compounds into valuable aromatic hydrocarbons is a critical step toward the sustainable valorization of renewable biomass. In this work, a cost‐effective, non‐noble metal‐based bimetallic Ni2Fe@HZSM‐5 catalyst was developed and systematically evaluated for its efficiency in converting lignin model compounds, vanillin, under mild reaction conditions. The optimized catalyst was synthesized by co‐impregnation of iron and nickel precursors onto a HZSM‐5 zeolite support, achieving a total metal loading of 10 wt.% with a Ni:Fe atomic ratio of approximately 2:1. Extensive characterization using X‐ray diffraction (XRD), scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM‐EDS), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area analysis, thermogravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS), and potentiometric acid strength measurements confirmed the effective anchoring and homogeneous dispersion of NiFe metal particles on the HZSM‐5 support, and excellent thermal stability of the prepared catalyst. Catalytic tests were conducted at 200°C using isopropanol (IPA) as both the reaction solvent and the in‐situ hydrogen donor, without the use of any external hydrogen gas. The Ni2Fe@HZSM‐5 Catalyst achieved highest conversion of vanillin with higher selectivity toward creosol formation with 80% yield.