Improving hydrodeoxygenation over Ni-Mo/Al2O3 by tuning the textural properties of the support via doping with lanthanoid group metals

Abstract Catalyst performance is one of the most decisive aspects for adding value to the industrial prospects of the hydrodeoxygenation (HDO) of lignin-derived oils to fuels. Deactivation of the catalyst, associated with blockage of pores and active sites due to diffusion limitations and the polymerization of bulky phenolic-type compounds, presents a significant challenge. In the present study, textural properties (pore diameter and surface area) are optimized by doping Al 2 O 3 with La- and/or Ce-precursors prior to inducing a phase transformation and pore coarsening through heat exposure. Response surface methodology and analysis of variance were applied to evaluate the optimal ratios (between 0 and 5 wt%) of the dopants to maximize the pore diameter while preserving the surface area for three different impregnation approaches. The dopants were either impregnated simultaneously or separately and calcined at 1100 °C–500 °C. Finally, the overall performance of synthesized Ni-Mo catalysts, supported on doped Al 2 O 3 , for the HDO process of vanillin under continuous-flow conditions ( T = 314 °C, P = 5 bar(g), and WHSV = 35 h − 1 ) was assessed. Statistically significant regression models for tuning the textural properties of the supports were developed, showing that a maximized pore diameter is obtained by doping with 5 wt% La. However, the findings of this study indicate that Ni-Mo/Al 2 O 3 catalysts doped with 1 wt% La and 1 wt% Ce are favored for the direct HDO process. An additional beneficial aspect is the low amount of carbon deposition on these catalysts.