Simultaneous Time-Resolved Photoluminescence and X-Ray Absorption Fine Structure Operando Measurement during Ag Cluster Formation in Ag Zeolite X

Abstract

We use operando X-ray absorption fine structure (XAFS) to analyze the relation between the properties of photoluminescence (PL) and the structures of Ag clusters and Ag ions. The Ag clusters are generated by evacuation in the cavity of Ag-type zeolite-X. The Ag clusters in the zeolite cavity collapse when exposed to the atmosphere. The results reported herein indicate that the collapsing Ag cluster plays an important role in generating strong PL bands and that Ag clusters might not be a direct species of PL. Results of XAFS analysis show that the Ag cluster formed in the zeolite cavity by evacuation can be tetrahedral with four atoms. By evacuation, 9 or 10 Ag tetrahedral are formed, two of which are expected to be responsible for strong PL. This result suggests that the Ag ion position after cluster collapse plays an important role in PL band generation and that Ag clusters are not direct luminescent species of PL.