Luminescence Control of Silver Nanoclusters by Tailoring Extra-Framework Cations in FAU-Y Zeolite: Implications for Tunable Emission

Silver nanoclusters (Ag NCs) are emissive centers that are characteristic of high quantum yield, tunable emission, and large Stokes shift when confined inside zeolites, and their luminescence property is closely related to the cluster size, charge state, local environment, and extra activation. In this research, we evaluated the luminescence response of Ag NCs on the extra-framework cations by considering Na-type FAU-Y (NaY) as the parent zeolite. The extra-framework cations Na+ were partially substituted with Li+ or Ca2+ through the ion-exchange method and analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) measurements, based on which a series of MYAg (M = Na, Li, Ca) zeolites were prepared through subsequent Ag+ exchange and thermal treatment under 600 °C for 2 h. The influence of extra-framework cations on the lattice parameter of the host zeolite, the exchange efficiency of Ag+, the formation ability, and the chemical state and luminescence property of Ag NCs was studied through the combination of structural and spectral measurements. This research indicated a flexible pathway for manipulating the luminescence property of Ag NCs, and the extra-framework cation-dependent luminescence property enables the FAU-Y zeolite to become a desirable host for the stabilization of Ag NCs to achieve highly efficient tunable emission.