A zirconium(IV)-based metal–organic framework modified with ruthenium and palladium nanoparticles: synthesis and catalytic performance for selective hydrogenation of furfural to furfuryl alcohol

Abstract

The conversion of biomass into sustainable biofuel is achievable through biorefinery. In this regard, the selective hydrogenation of furfural to furfuryl alcohol, 2-methylfuran, and tetrahydrofurfuryl alcohol has attracted a great interest. This research aims to prepare an active and selective catalyst for hydrogenation of furfural in liquid phase. To achieve this objective, we employed a water-stable zirconium(IV)-based metal–organic framework (MOF) [Zr6O4(OH)4(BTC)2(CH3COO)6] (Zr–BTC) (BTC = benzene-1,3,5-tricarboxylate) and modified it with Ru and Pd to form Ru/Zr–BTC and Pd/Zr–BTC. The diffractograms of Zr–BTC modified with Ru and Pd metal fit well with the diffractogram of the pristine Zr–BTC, indicating that the presence of Ru and Pd in Zr–BTC does not change the Zr–BTC structure. This is further confirmed by FTIR spectra. The obtained materials showed type I adsorption isotherms, thus the material can be classified as microporous. The presence of Pd/Ru metal on the surface and in the pores of Zr–BTC decreases the total pore volume and BET surface area. Electron microscopy (SEM and TEM) analysis further confirmed that the Pd and Ru were successfully encapsulated in Zr–BTC. Ru/Zr–BTC and Pd/Zr–BTC showed excellent performance in the catalytic liquid-phase hydrogenation reaction of furfural to furfuryl alcohol with conversion of 99.4% and 98.4% for Ru/Zr–BTC and Pd/Zr–BTC, respectively, and selectivity to furfuryl alcohol (FA) up to 100% for both catalysts