(532c) Morphology-Dependent Catalytic Activity of Wrinkled Silica Sphere Supported Palladium for One-Pot Furfural Hydrogenation

With diminishing the fossil fuels and increasing the global warming issues, the development of alternative energy resources has been attracted. Upgrading biomass-derived materials has been widely studied to transform the renewable biofuels and high value-added chemicals. Herein, we prepared the various wrinkled silica sphere (KCC) by tuning the surfactant to silica precursor ratio of 0.1 to 0.4. Then, Pd/KCC catalysts were synthesized by chemical reduction method for hydrogenation of furfural (FF). The catalyst names were denoted as Pd/KCC X, where X is the surfactant to silica precursor molar ratio. We also prepared Pd/SiO₂ nanosphere for comparison. Interestingly, higher surfactant concentration generated the reduced fiber density and particle size by inhibiting the nucleation and growth of silica nanoparticles. In addition, the interwrinkle distance and wall thickness of wrinkled silica were enhanced and the large specific surface area and porosity of catalysts were observed. Therefore, we found that the decrease in fiber density was accompanied by increase in pore size and volume. All the catalysts were conducted for one-pot hydrogenation of FF. All the Pd/KCC catalysts and Pd/SiO₂ showed similar conversion of FF to tetrahydrofurfuryl alcohol (THFAL). Pd/KCC 0.3 revealed the highest THFAL yield (87.4%) in aqueous media within 4 h at 35 ℃, indicating that THFAL yield of Pd/KCC 0.3 had two-fold higher than that of Pd/SiO₂. This can be explained that the low fiber density led the higher absorption of reactants and the higher activity for FF hydrogenation due to its unique structure with mesopores and the widely wrinkled pore structures. These structures improved the catalytic activity due to the high mass transfer. The variation of FF conversion and THFAL selectivity with reaction time and temperature over Pd/KCC 0.3 were also investigated. The highest THFAL yield was achieved to 96.2% at 70 ℃ for 4 h.