Aqueous phase hydrogenolysis of glycerol over Ni/Al-Fe catalysts without external hydrogen addition

The present work studied the aqueous phase hydrogenolysis (APH) of glycerol (a by-product of biodiesel manufacturing) without external hydrogen addition to produce value-added products. A series of catalysts based on 28 molar % of Ni were prepared through co-precipitation by changing the Al/Fe molar ratio. The calcined and used catalysts were characterized by several techniques (ICP-OES, N2-physisorption, XRD, H2-TPR, NH3-TPD, FESEM and STEM). This work examines the effects of the molar ratio of Al/Fe on the physicochemical characteristics of Ni/Al-Fe catalysts and during the APH of glycerol. All the catalysts showed low carbon yields to gases and high carbon yields to liquid products, mainly 1,2-propanediol, acetol and ethylene glycol. Ni/Al3Fe1 catalyst gave the best performance in the APH of glycerol: the highest glycerol conversion (42.31 %), carbon yield to gases (6.57 %) and carbon yield to liquids (30.45%). 1,2-propanediol was the liquid product with the highest carbon selectivity (70.89%).