Solvent-free crystallization of ZSM-5 zeolite on SiC foam as a monolith catalyst for biofuel upgrading

Abstract

Conventional synthesis of monolith-supported zeolite catalysts is based on a hydrothermal strategy. Here, we report a solvent-free crystallization process to coat ZSM-5 zeolite crystals on a monolithic SiC foam with a honeycomb structure (ZSM-5/SiC). Characterizations of the ZSM-5/SiC by scanning electron microscopy, N2 sorption, and X-ray diffraction indicate that the zeolite sheath has been ideally coated on the surface of the SiC foam with high purity and crystallinity. Fixing Pd nanoparticles within the ZSM-5 zeolite crystals delivers a bifunctional Pd@ZSM-5/SiC catalyst, which exhibits high activity and selectivity toward diesel range paraffins in the hydrodeoxygenation of methyl oleate, a model molecule for biofuel. In comparison to the powder Pd@ZSM-5, the Pd@ZSM-5/SiC monolith catalyst shows more efficiency, which is attributed to the fast mass transfer and high heat conductivity on the honeycomb SiC structure. The durability test indicates that the Pd@ZSM-5/SiC catalyst is stable under the reaction and high-temperature regeneration conditions.