Application of nano-scale supported Au in catalytic hydrogenation delivers high chemoselectivity but low activity using (pressurized) H2 far in excess of stoichiometric requirements. We have tackled the issues of low reaction rate and inefficient hydrogen utilization through a series of approaches taking Au/CeO2 (mean Au size = 2.8 nm) as a test catalyst. Increased spillover hydrogen (using physical mixtures of Au/CeO2 with CeO2 and SiO2) and the promotional effect of water (via catalytic dissociation on surface oxygen vacancies) resulted in a fourfold increase in the selective rate of furfural hydrogenation to furfuryl alcohol. In contrast, Pd/CeO2 and Ni/CeO2 promoted decarbonylation (to furan), hydrogenolysis (to 2-methylfuran) and ring reduction (to tetrahydrofurfuryl alcohol). Coupling (2-butanol → 2-butanone) dehydrogenation over Cu/SiO2 (mean Cu size = 7.8 nm) with furfural hydrogenation over Au/CeO2 further increased rate with full utilization of the hydrogen generated in dehydrogenation. The coupling strategy allows “hydrogen free” hydrogenation that circumvents the limitation of Au in standard catalytic hydrogenation. This can open new avenues to exploit the ultra-selectivity of Au for continuous production of high value commodity products.
- Coupled dehydrogenation/hydrogenation
- Furfural hydrogenation
- Hydrogen utilization
ASJC Scopus subject areas
- Physical and Theoretical Chemistry