Hydrodeoxygenation of Guaiacol over Ni–Mo 2 C Catalysts: Effect of Synthesis Strategy on Activity and Selectivity

Abstract

Designing efficient catalysts for hydrodeoxygenation (HDO) is vital for upgrading biomass-derived feedstocks into cleaner fuels and high-added value chemicals. In this study, we investigated two distinct strategies for synthesizing Ni-modified molybdenum carbide (Mo2C) catalysts: a one-step microwave-assisted carburization method (NiMo2C) and a sequential approach involving incipient wetness impregnation of microwave-synthesized Mo2C with nickel nitrate (Ni/Mo2C). Comprehensive physicochemical characterization using XRD, XPS, SEM/EDS, TEM, BET, and H2-TPR revealed pronounced differences in structure and surface chemistry. These structural differences in morphology, dispersion, and metal-support interactions significantly influenced catalytic behavior. Ni/Mo2C demonstrated superior performance in guaiacol HDO achieving overall conversion of 98% mostly forming high H/C products (cyclohexane), which is exclusively displayed by this catalyst. Additionally, the catalyst displays high stability, enabling the same conversion to proceed for more than 10 hours. The findings underscore the critical role of synthetic pathways in tailoring the structure–function relationship of carbide-based catalysts for biomass conversion.