**2. Experimental**

### **2.1 Sample preparation**

Fully Ag<sup>+</sup> -exchanged zeolite X (hydrated 86Ag-X) powder samples were prepared by immersing the hydrated 86Na-X (Na86[(AlO2)86(SiO2)106], purchased from Tosoh Corp.) in 0.1 M AgNO3 solution for 24 h at 25°C. The solution was stirred continuously with a magnetic stirrer during ion exchange. After careful filtration, the 86Ag-X powder was dried under air at RT in the darkroom.
