Hydrophobic Zeolite Containing Titania Particles as Wettability-Selective Catalyst for Formaldehyde Removal

Abstract

This work delineates a concept of wettability-selective catalyst, which is realized by functionalizing a metal oxide catalyst within a zeolite sheath with controllable wettability. We synthesized such zeolite sheaths by anchoring organic groups (e.g., -CH3) into a faujasite framework during the crystallization, achieving hydrophobic micropores for selective capture of organic compounds but hindering water diffusion. Further fixation of TiO2 particles within these zeolite crystals resulted in core–shell catalysts denoted as TiO2@HP-zeolite, which combined the functions of both wettability selectivity for the zeolite sheath and photocatalytic activity for the TiO2. Owing to the synergism of these features, TiO2@HP-zeolite displayed superior performances in complete removal of wet formaldehyde in a long-period continuous test under irradiation of sunlight frequencies, outperforming the conventional catalysts with poor water tolerance.