Carbon laydown associated with furan hydrogenation over palladium/zirconia

The hydrogenation of furan over Pd/zirconia has been studied at 373 K and 1 atm and two hydrogen/furan ratios. As expected, significant carbon laydown occurs. From FTIR spectroscopy, the primary surface species are furan and THF. Contrary to expectations, no decomposition to carbon monoxide and a C3H3 moiety was observed, i.e., no carbon monoxide was detected. The infrared assignments were confirmed by TPR over the used catalysts using hydrogen, which resulted in the desorption of THF, indicating that the fracture of the ring did not occur under hydrogenation conditions. At high temperatures, methane was formed under TPR conditions from the hydrogenolysis of adsorbed furan/THF. TPO and TPR confirmed the presence of retained species with varying surface energetics related to their chemical natures and their adsorption sites.