Comparison study of titania pillared interlayered clays and porous clay heterostructures modified with copper and iron as catalysts of the DeNOx process

Natural montmorillonite was used as a raw material for the preparation of titania pillared clays (Ti-PILC) and porous clay heterostructures (Ti-PCH). Ti-PILC was produced by direct exchange of interlayer sodium cations in montmorillonite (sodium form) for titanium oligocations. Ti-PCH was obtained by the surfactant directed method. Tetraethylorthosilicate and titanium isopropoxide were used as the source of silica and titania, respectively. Copper and iron were introduced to Ti-PILC and Ti-PCH by the ion exchange method. The obtained materials were characterized with respect to chemical composition (EPMA), structure (XRD) and texture (BET), coordination and aggregation of transition metal species (UV–vis-DRS) and surface acidity (FT-IR). Modified montmorillonites were found to be active and selective catalysts for the reduction of NO with ammonia (DeNOx process) and their catalytic performance depended on the type of support (Ti-PILC or Ti-PCH) as well as deposited transition metal (Cu or Fe) species.

Research Highlights
► Montmorillonites pillared with TiO2 or SiO2-TiO2 were tested as catalysts for DeNOx.
► Ti-PILC was obtained by intercalation of Ti-oligocations into clay interlayer space.
► Ti-PCH (clay pillared with SiO2-TiO2) was obtained by surfactant directed method.
► Ti-PILC and Ti-PCH modified with Cu and Fe were active catalysts of DeNOx process.
► The studies showed that DeNOx process proceeds according to Eley-Riedel mechanism.