Nickel aluminate spinel-derived catalysts for aqueous-phase hydrogenolysis of glycerol with in-situ hydrogen production: Effect of molybdenum doping.

The correlation between the physico-chemical properties of bare and Mo-doped nickel aluminate derived catalysts and product distribution during hydrogenolysis of glycerol with in situ produced hydrogen in continuous was investigated. Stoichiometric nickel aluminate spinel was synthesized via citrate sol-gel in a one-pot synthesis and subsequently doped it with 1 wt% Mo, using both sol-gel one-pot and impregnation methods. Catalytic runs were performed at 235 ºC/ 45 bar for 4 h TOS. The results indicate that Mo-doping increased the number of both metal and acid sites, leading to more selectivity towards deoxygenated products. 1,2-propylene glycol was the major liquid product, Mo/NiAl catalyst exhibited the highest yield (27%) and selectivity (39%). Post-reaction characterization revealed that leaching and oxidation of metals could potentially cause catalyst deactivation. 1 wt% Mo-doped nickel aluminate-derived catalysts possess potential for the selective production of 1,2-PG in a eco-friendly process through one-pot coupling H 2 generation and hydrogenolysis reactions. [Display omitted] • NiAl 2 O 4 is doped with 1 wt% Mo using both sol-gel and impregnation methods. • Catalysts are evaluated for 1,2-PG production via H 2 -free glycerol HDO. • Mo doping hinders Ni reducibility and increases the metal and acid sites densities. • Mo/NiAl catalyst achieves X Gly = 69%, Y 1,2-PG = 27% and S 1,2-PG = 39%. • Negligible deactivation is observed throughout the four-hour reaction duration. [ABSTRACT FROM AUTHOR]