Nickel‐Hydroxyapatite Catalyst for Lignin‐Derived Vanillin Hydrodeoxygenation and Kinetic Study

ABSTRACT The exploration of the catalytic activity of lignin‐derived compounds into high‐value‐added chemicals is essential to meet the rising energy demands and to provide an alternative to fossil fuels. In this study, a non‐noble metal catalyst was used for the vanillin hydrodeoxygenation (HDO) process. The low‐cost Ni/HAP catalyst was prepared using the wet impregnation method with varying nickel loadings on a hydroxyapatite (HAP) support. Comprehensive physiochemical characterization was carried out using XRD, SEM‐EDX, XPS, NH 3 ‐TPD, CO chemisorption, HR‐TEM, and Nitrogen adsorption‐desorption analysis. Among the studied catalysts, the 1‐Ni/HAP catalyst exhibited superior catalytic activity for vanillin HDO to 2‐methoxy‐4‐methylphenol (MMP). The catalyst shows broader applicability for other lignin‐derived aromatic aldehyde compounds. The Langmuir‐Hinshelwood‐Hougen‐Watson (LHHW) model was developed to understand the reaction kinetics and mechanism. The activation energy of 88.76 kJ/mol indicates that the vanillin HDO reaction is kinetically controlled. These findings establish Ni/HAP as an active, selective, and non‐noble metal catalyst for lignin‐derived aldehyde valorization.