In-situ one-step deposition of highly dispersed palladium nanoparticles into zirconium metal–organic framework for selective hydrogenation of furfural

Abstract

• Pd nanoparticles are deposited on SBUs of UiO-66 by an in-situ method. • UiO-66-Pd catalyst is active in the furfural hydrogenation in liquid phase. • The UiO-66-Pd shows 71% furfural conversion and 94% furfuryl alcohol selectivity. • In comparison to two-step method, UiO-66-Pd demonstrates higher activity (17%). Palladium nanoparticles highly dispersed into UiO-66 as an efficient and selective hydrogenation catalyst is synthesized by a one-step in-situ method of incorporation of the Pd centers on the secondary building units (SBUs) of UiO-66 as the support and compared to a two-step method. Using DMF as both a solvent and a reducing agent, HCl as an enhancer of the terminal OH groups on Zr-clusters by linker elimination, and a temperature profile result in the incorporation of Pd precursor at lower temperatures and generation of Pd nanoparticles at higher temperatures. The catalysts were characterized by BET surface area measurement, SEM, XRD, HR-TEM, XPS, H 2 -TPR, and CO pulse chemisorption methods. The regulation of the temperature and time in the one-step method results in the formation of Pd nanoparticles embedded in the MOF with a higher dispersion and accessibility in comparison to the two-step method. An automated high-pressure semicontinuous setup was used for the furfural hydrogenation. The 1 wt% Pd on UiO-66 exhibits a high conversion of 71% and selectivity of 94% for hydrogenation of furfural to furfuryl alcohol in the liquid phase at 20 bar H 2 , 110 ˚C and 4 h reaction. The catalyst was used repeatedly without significant deactivation.