Synergistic impact of Cu and support materials in Ni-based catalysts for glycerol hydrogenolysis to 1,2-propanediol

Selective hydrogenolysis of glycerol to 1,2-propanediol (1,2-PD) represents an essential evaluating process for the valorization of glycerol. In this research, a series of Ni- and Ni–Cu-based catalysts supported on SiO 2 , SiO 2 –Al 2 O 3 , and titanium (IV) oxide (TiO 2 ), were prepared via the sequential wetness impregnation approach and evaluated for their performance in glycerol hydrogenolysis. The results indicated that the 25Ni-10Cu/TiO 2 catalyst exhibited strong catalytic efficiency in glycerol hydrogenolysis, showing 72.9% conversion of glycerol and 85.8% selectivity to 1,2-PD (62.5% yield) after 24 h reaction time. This enhanced performance is attributed to the optimal balance and synergy between the acidity of the support and the active metal sites, promoting both dehydration and hydrogenation reactions. The presence of Cu in the catalyst system was found to significantly enhance glycerol hydrogenolysis while inhibiting unwanted side reactions. In contrast, monometallic Ni/SiO 2 demonstrated the lowest conversion of glycerol (33.8%) at 24 h, while bimetallic Ni–Cu/SiO 2 and Ni–Cu/SiO 2 –Al 2 O 3 catalysts exhibited high activity, with glycerol conversion rates exceeding 91%. These findings demonstrate that incorporation of Ni with Cu is essential for optimizing both catalytic efficiency and selectivity, particularly when combined with supports like TiO 2 .