Post-Synthesis Modification of Zirconium(IV)-BTC Based MOF with Palladium Nanoparticles as Catalyst in the Hydrogenation Reaction of Citronellal

The objective of this research is to investigate the effect of palladium insertion into zirconium(IV)-based Metal-Organic Frameworks (MOFs) containing a benzene 1,3,5-benzenetricarboxylate organic linker [Pd/Zr6O4(OH)4(O2C2H3)6(BTC)2] or (Pd/Zr-BTC) on its structure and its ability to catalyze the hydrogenation process of citronellal. Zr-BTC was synthesized by a modulated-solvothermal method at 135 degrees C. Post-synthesis modification with Pd nanoparticle was conducted using the wet impregnation method with a concentration of 2.5% (w/w). Powder XRD analysis showed that the presence of Pd was identified by a new peak at 2 theta = 40.0 degrees and the decrease of Zr-BTC crystallinity. The presence of Pd also increases the irregularity of Zr-BTC morphology and contains an average particle size up to 16.58 +/- 6.4 nm according to SEM and TEM analysis. Modification with Pd lead to a decrease in surface area, pore volume, and diameter of Zr-BTC up to 1095 m2/g, 0.15 cc/g, and 18.6 angstrom, respectively. Moreover, the addition of Pd does not affect the thermal stability of Zr-BTC. An examination of the hydrogenation of citronellal was carried out using two distinct setups. The first involved conducting reactions in a batch reactor system at a temperature of 80 degrees C and under a hydrogen pressure of 10 bar for a duration of 6 h. The second approach entailed performing reactions in a hydrogen-filled balloon under atmospheric pressure (1 atm) at 80 degrees C for a period of 6 h. The addition of Pd into Zr-BTC increases its activity up to 83.2%, and selectivity (up to 53.7%) in citronellal hydrogenation for both batch and balloon systems. Interestingly, the employment of batch reactors is found to be more effective.