Carbonized UiO-66 with Ni nanoparticles for PFAD deoxygenation to green diesel hydrocarbons: Characterization, optimization and deactivation analysis

Abstract

Fabricating effective reusable catalysts for biomass deoxygenation is essential for sustainable fuel production. In this study, Ni nanoparticles (15-25 wt%) were incorporated into UiO-66 through solvothermal synthesis, followed by partial carbonization at 300°C to improve thermal stability, dispersion and catalytic efficiency in palm fatty acid distillate deoxygenation. Structural analysis confirmed that the UiO-66 framework remained intact after Ni incorporation, with X-ray photoelectron spectroscopy indicating well-dispersed Ni species (Ni2p 3/2 at 855.6-856.7 eV). The acid-base characteristics and high surface area supported the cleavage of C-O and C-C bonds. Among the catalysts tested, C-UiO-66@Ni-20wt% showed the best performance, achieving an 87.65% hydrocarbon yield under conditions (3.14 h, 3.28 wt% catalyst, 340°C) optimized by response surface methodology. The reliability of the model was confirmed by a high R² value (99.47%) and statistical significance (p < 0.0001). The catalyst maintained stable activity over seven cycles, with only a 2-7% yield reduction per cycle, before significant deactivation occurred in the eighth cycle owing to pore blockage and active site agglomeration. This study illustrates that Ni-doped UiO-66, with its balanced acidity, structural integrity and efficiency at low temperatures, is a promising catalyst for scalable biofuel production, offering both high reactivity and reusability.