X-ray Absorption Spectroscopy of Bimetallic Pt-Re Catalysts for Hydrogenolysis of Glycerol to Propanediols

Bimetallic Pt-Re nanoparticles supported on Norit carbon were effective at converting aqueous glycerol to 1,3 (34%) and 1,2 (33%) propanediol at 443 K under 4 MPa of H-2. Results from Xray absorption spectroscopy and analytical transmission electron microscopy confirmed that the nanoparticles were indeed bimetallic, with a particle size less than 2 nm in diameter. The Pt L-III near edge spectra indicated that the Pt was reduced to the metallic state by treatment in H-2 at 473 K, but that a partial positive charge remained on the Re. These oxidized Re species could be associated with charged Re atoms dispersed on the carbon support because spillover of H atoms from Pt was required to reduce Re in the bimetallic particles.