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.

Advances in porous and nanoscale catalysts for viable biomass conversion

“…However, this process involves the utilization of environmentally unfriendly media, such as NaF, NH 4 F, and HF. 516 In contrast, the functionalization of zeolites by silylation approach has attracted much attention as this strategy allows the anchoring of hydrophobic organosilane groups on the external/ internal surfaces of the zeolites. 113,490,513,517 This hydrophobization route using organosilanes can impede the interactions of water molecules with zeolites, thus stabilizing the framework against harsh hydrothermal conditions (Fig.…”

Thermally treated zeolitic imidazolate framework-8 (ZIF-8) for visible light photocatalytic degradation of gaseous formaldehyde

“…The photocatalytic performance of ZIF-8-T3 is signicantly better than those of recently reported photocatalysts for HCHO degradation under similar experimental conditions. 6,[42][43][44][45] The stability and reusability of ZIF-8-T3 were investigated by repeating the photocatalytic HCHO degradation with recycled ZIF-8-T3, as shown in Fig. S9.…”

“…It is well acknowledged that the performance of catalysts is strongly inuenced by water species. 42 To understand the effect of water species on the photocatalytic performance of ZIF-8-T3, the HCHO degradation experiments were carried out at low, ambient, and high relative humidity (RH). Fig.…”

Incorporation of Active Metal Species in Crystalline Porous Materials for Highly Efficient Synergetic Catalysis

“…Constructing a hydrophobic surface/framework can tune the zeolite environment, thus cooperating with MNPs and often producing unexpected catalytic effects in some specific chemical reactions. [186][187][188][189][190] For instance, in 2018, Xiao et al synthesized a core-shell Pd@S-1 zeolite catalyst with controllable wettability (Pd@S-1-OH) by functionalizing silanol groups into the zeolite framework (Figure 19a). [191] The resulted sample exhibited an extraordinary performance in the hydrogenation of furfural (Figure 19b), with a selectivity of furan as high as >99.9% and a 100% conversion of furfural, outperforming the Pd@S-1 catalyst without artificially functionalized silanol groups (Figure 19c,d).…”