Catalytic Transfer Hydrogenolysis of Bio-Polyols to Renewable Chemicals over Bimetallic PtPd/C Catalysts: Size-Dependent Activity and Selectivity

Abstract

Most industrial hydrogenation processes are conducted under elevated temperature and pressure. Catalytic transfer hydrogenation/hydrogenolysis, in the absence of externally added hydrogen, is known to be much more energy efficient and atom economical. However, the multifunctional nature of catalyst structure on simultaneous hydrogen generation, hydrogen transfer, and hydrogenation reactions is largely unexplored. We reported a design principle and size-dependent behavior of bimetallic PtPd/C catalysts for transfer hydrogenolysis of bioderived polyols to renewable glycols as an illustrative example. The central finding in this work is that, while kinetics of partial dehydrogenation (C–H cleavage) display size insensitivity, reforming (C–C cleavage) and hydrogenolysis (C–O cleavage) reactions show strong size-determining activity and selectivity in the range of 2.0 to 5.3 nm. The synergistic PtPd/C catalysts lead to a remarkable selectivity of 87% for value-added glycols and derivatives even under an inert atmosphere. The outcome from this fundamental study will provide insights into the structural design of next-generation solid catalysts for energy efficient hydrogenation processes.