Influence of Catalyst Reduction Temperature on Autogenous Glycerol Hydrogenolysis over NiAl Catalyst

Autogenous glycerol hydrogenolysis to 1,2‐propanediol by aqueous phase reforming (APR) was investigated over supported nickel catalysts. Effect of reduction temperature on physico‐chemical properties of catalysts played a significant role in tuning conversion and product selectivities. The formation of nickel aluminate (NiAl2O4) spinel phase during catalyst reduction led to rearrangement of Ni species to obtain small and stable Ni particles. The catalyst activation temperature alters the extent of reduction of multivalent Ni species (Ni0, Ni+2/+3) which facilitated glycerol dehydration and hydrogenation while suppressing C−C cleavage and thus avoiding undesirable side products. Additionally, presence of moderate BrØnsted/Lewis acid ratio of the catalyst promoted higher 1,2‐PDO selectivity. In‐situ glycerol hydrogenolysis involves glycerol dehydration to acetol with simultaneous reforming to H2 and CO2 and this hydrogen converts acetol to 1,2‐PDO. Hydrogen generation through aqueous phase reforming of glycerol followed by its in‐situ hydrogenation was achieved over NiAl catalyst. NiAl reduced at 600 °C showed the highest activity for autogenous glycerol hydrogenolysis to the desirable product,1,2‐PDO. The reduction temperature significantly influenced the acidity and formation of various Ni species.