Palladium confined in pure-silica TON zeolite for furfuryl alcohol hydrogenation into tetrahydrofurfuryl alcohol

Abstract

Fabrication of robust noble metal nanoparticles (NPs) usually suffers from instability due to the large surface energy of small particles. Herein, highly dispersive Pd nanoparticles (average size: ~3 nm) with controllable content were directly encapsulated within pure silica zeolite matrix with TON topology via a dry gel conversion pathway, in which 1-butyl-3-methylimidazolium bromide and (3-mercaptopropyl) trimethoxysilane were utilized as the structure-directing agent and metal stabilizer, respectively. High crystallinity and large surface area were reached over this Pd containing zeolites. The champion catalyst Pd–Si-ZSM-22 effectively catalyzed the transformation of furfuryl alcohol into tetrahydrofurfuryl alcohol via hydrogenation by using H2. High conversion (>99%) and selectivity (>99%) were reached with large turnover numbers and the stable activity was observable during the recycling test. The comparison with the post-impregnated counterpart indicates that the straightforward synthesis is favorable for the construction of stable and robust Pd species within the confined microchannels of TON zeolites.