On thermal stability and catalytic reactivity of Zr-metal-organic framework (UiO-67) encapsulated Pt catalysts

摘要

Pt nanoparticles (NPs, 0.5 wt.%) encapsulated in a zirconium-based metal-organic framework (UiO-67 MOF) were synthesised via a linker design method. Thermal behaviours of Pt in UiO-67 composite materials were studied using thermogravimetric and differential thermal analysis (TG-DTA) in comparison with UiO-67. TG-DTA results showed that Pt insertion can impair the thermal stability of the bulk UiO-67 resulting in a ca. 14% drop in the critical temperature of the thermal decomposition. Temperature-programmed oxidation of materials showed that calcination at 450 K was essential to render a clean framework. Temperature-programmed reduction of materials revealed that the chemisorption of H2 on UiO-67 (at 323 K) was evidently enhanced owing to the incorporation of Pt NPs thus making PtNP@UiO-67 suitable for hydrogenation reactions and hydrogen storage. PtNP@UiO-67 catalyst was evaluated by the oxidation and hydrogenation of 5-hydroxymethylfurfural in aqueous solutions at 363 K showing an improved activity and selectivity in hydrogenation reactions.