A versatile route to fabricate Metal/UiO-66 (Metal = Pt, Pd, Ru) with high activity and stability for the catalytic oxidation of various volatile organic compounds

Abstract

The supported noble metal catalysts have been demonstrated outstanding catalytic performance for the catalytic degradation of volatile organic compounds (VOCs), but their high cost, easy poisoning and sintering deactivation limit their further applications. Herein, we proposed a flexible and universal strategy to prepare the highly dispersed metal nanoparticles (Pt, Pd, Ru) supported on metal–organic frameworks (metal/MOFs) through the impregnation-reduction method for the catalytic oxidation of VOCs. Metal/MOFs integrate MOFs with large surface area and high porosity for supplying VOCs adsorption sites and highly dispersed metal species for offering catalytic active sites. For example, Pt/UiO-66 NPs exhibited nearly 100% conversion efficiency and CO2 yield for the catalytic oxidation of various VOCs including ethyl acetate (260 °C), n-hexane (260 °C) and toluene (180 °C). Particularly, there was no obvious difference in the morphology, size, distribution, crystallinity, and composition of the fresh and used Pt/UiO-66 NPs from the TEM images, XRD spectra and XPS analysis. Besides, a series of metal/MOFs (Pt, Pd, Ru) exhibited high reusability, good water resistance as well as excellent stability over 150 h on the on-stream reactions for the degradation of ethyl acetate. Furthermore, the catalytic oxidation mechanism and pathways were revealed by the study of active sites and reaction intermediates via X-ray photoelectron spectroscopy (XPS), in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and proton transfer reaction-time of flight mass spectrometer (PTR-TOF-MS). We anticipate that this work may shed light on developing noble metal catalysts supported on porous materials for novel applications in environmental catalysis.