Continuous Control over Zeolite Porosity via the Post-Synthesis Treatment of the IWV Zeolite

The control over microporosity is crucial for the practical application of zeolites. Here, we report a series of daughter zeolites with related structure prepared via the ADOR (assembly-disassembly-organization-reassembly) post-synthesis of the germanosilicate IWV zeolite. Concentrated HCl was selected as the hydrolysis medium because of its superior efficiency in the disassembly of the IWV zeolite framework and the ordering preservation. The treatment of the IWV zeolite (Si/Ge = 7.5) at room temperature yielded the formation of an intermediate with preserved silicate layers while contracted interlayer spacing (d₂₀₀) via the selective removal of Ge-rich double-four ring (D4R) units. The subsequent treatment at elevated temperatures stimulated the continuous expansion of the interlayer spacing and the reinsertion of siliceous D4R dopants, leading to a series of daughter zeolites with related structures, including the ultimate restored siliceous IWV structure. The d₂₀₀ values and textural properties (surface area and micropore volume) of the daughter zeolites monotonically increase with the heating duration, followed by approaching a maximum. In this context, these parameters can be continuously regulated simply by adjusting the heating durations. Moreover, similar correlations are observed when different heating temperatures or parent IWV zeolites with different Ge contents were utilized, proving the versatility of the present approach.