Sustainable H2-free glycerol hydrogenolysis to 1,2-propylene glycol using vanadium- and boron-doped nickel catalysts
A.J. Reynoso, D. Gallego-García, M.A. Gutiérrez–Ortiz, Unai Iriarte‐Velasco, J.L. Ayastuy
Abstract
A series of vanadium- and boron-doped nickel aluminate spinel catalysts (0.5, 1, and 3 wt%) were synthesized via a one-pot sol-gel method and tested for glycerol hydrogenolysis to 1,2-propylene glycol using in situ hydrogen at 235 °C and 45 bar. The highest catalytic performance was observed for the catalysts doped with 1 wt% V and B, achieving glycerol conversions of 82.5 % and 86.0 %, respectively, and 1,2-propylene glycol yields of 33.6 % and 26.0 % after 28 h time-on-stream. Characterization showed that metal accessibility, acidity, and redox properties had a significant influence on glycerol conversion, 1,2-propylene glycol yield, space-time yield, and catalyst stability. Low V or B doping levels (0.5–1 wt%) preserved metal dispersion, enhancing stability and 1,2-propylene glycol selectivity, while higher doping (3 wt%) resulted in larger Ni particles, leading to decreased catalytic activity. Acid-metal interactions played a critical role in optimizing hydrogenolysis pathways, particularly in the dehydration of hydroxyacetone and its subsequent hydrogenation. Post-reaction analysis revealed minimal carbon deposition but significant boron leaching, whereas vanadium doping improved nickel sintering resistance. These results demonstrate the potential of V- and B-doped nickel catalysts for sustainable glycerol valorization, enabling high catalytic efficiency without the need for external hydrogen. • Glycerol hydrogenolysis without external H 2 over V and B doped nickel aluminate. • 1 wt% V/B doping boosts 1,2-PG yield (33.6 % V, 26.0 % B) after 28 h TOS. • Low doping (0.5–1 wt%) enhances Ni dispersion, stability, and selectivity. • Boron leaches heavily (77 %) but does not damage long-term catalyst performance. • Vanadium improves Ni 0 sintering resistance, preserving catalyst structure.