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-PDO in a eco-friendly process through one-pot coupling H2 generation and hydrogenolysis reactions.