Zeolite-supported silver and silver–iron nanoclusters and their activities as photodecomposition catalysts

Abstract

Catalysts containing nanoclusters of Ag(I) and Fe 2 O 3 as dopants with sodalite and Y zeolite supports have been investigated in order to develop a more efficient catalyst for photodecomposition of the pesticide carbaryl and to gain insight about the reaction mechanism. Ag(I)-sodalite, Ag(I)/Fe 2 O 3 -sodalite, Ag(I)-Y zeolite, and Ag(I)/Fe 2 O 3 -Y zeolite were synthesized by ion-exchange techniques and characterized by powder X-ray diffraction (XRD), solid-state luminescence, UV-visible absorption, and atomic absorption spectroscopy measurements. The luminescence activity of the sodalite-supported and Y zeolite-supported catalysts was significantly different. Catalyst performance studies were conducted using carbaryl as the target compound and specific wavelengths of UV light as photon sources for the experiments. The studies showed that each catalyst's performance was determined primarily by the specific wavelength of the UV light with which the system was irradiated. The studies also showed that inclusion of Fe 2 O 3 as dopant enhanced the reactivity of the catalysts in several instances, with the Ag(I)/Fe 2 O 3 -sodalite catalyst and 298 nm irradiation being the most reactive of the systems studied. Additional reactions using each catalyst and 298 nm irradiation, and including either sodium bicarbonate as hydroxyl radical scavenger or D 2 O as solvent, showed that hydroxyl radicals were likely intermediates in the catalyzed photodecomposition reaction.

From 3D to 2D zeolite catalytic materials

“…Zeolites have also been employed as supports for a wide variety of active phases in order to modify and complement their properties. [54][55][56][57][58][59] These active phases include metals, metal oxides, metal salts and metal complexes, generating materials with multifunctional properties and applications in a great variety of reactions in various sectors such as oil refining, petrochemistry, fine chemicals, waste valorization, pollutant removal in gaseous and liquid streams, biofuel production, etc.…”

Ag2(0) dimers within a thioether-functionalized MOF catalyze the CO2 to CH4 hydrogenation reaction

“…However, silver is an exception here, since the extraordinary tendency of silver atoms to reduce (even with just light) and aggregate in nano- and micro-particles hampers the formation of ultrasmall metal clusters 10 , 11 . In particular, catalytic ligand-free silver dimers in reduced state (Ag 2 ) have been obtained with electrochemistry techniques 12 , under size-selected synchrotron conditions 13 – 15 or by supporting them in porous solids 16 .…”

Tailoring the Luminescence Properties of Silver Clusters Confined in Faujasite Zeolite through Framework Modification

“…Luminescent Ag clusters (Ag CLs) that consist of several silver ions and silver atoms have attracted wide research interest for photocatalysis, imaging, detection, and illumination applications due to their remarkable optical properties including strong absorption of UV light, tunable emission in the visible region, large Stokes shifts, and high quantum efficiency approaching commercial phosphors [ 1 , 2 , 3 ]. However, Ag CLs easily aggregate into larger silver nanoparticles (Ag NPs) due to their high surface energy and thus lose radiative emission ability [ 4 , 5 ].…”