Catalytic hydrodeoxygenation of m-cresol over Ni2P/hierarchical ZSM-5

Bifunctional catalysts comprising Ni 2 P supported over a hierarchical ZSM-5 zeolite (h-ZSM-5) were synthesized and applied to the hydrodeoxygenation (HDO) of m-cresol, a model pyrolysis bio-oil compound. Surface and bulk characterization of Ni 2 P/h-ZSM-5 catalysts by XRD, TEM, DRIFTS, TPR, porosimetry and propylamine temperature-programmed desorption reveal that Ni 2 P incorporation modifies the zeolite textural properties through pore blockage of the mesopores by phosphide nanoparticles, but has negligible impact of the micropore network. Ni 2 P nanoparticles introduce new, strong Lewis acid sites, whose density is proportional to the Ni 2 P loading, accompanied by new Brönsted acid sites attributed to the presence of P-OH moieties. Ni 2 P/h-ZSM-5 is ultraselective ( > 97%) for m-cresol HDO to methylcyclohexane, significantly outperforming a reference Ni 2 P/SiO 2 catalyst and highlighting the synergy between metal phosphide and solid acid support. m-Cresol conversion was proportional to Ni 2 P loading reaching 80 and 91% for 5 and 10 wt% Ni respectively. Turnover frequencies for m-cresol HDO are a strong function of Ni 2 P dispersion, evidencing a structure sensitivity, with optimum activity observed for 4 nm particles.