Controllably Confined ZnO on USY Zeolites (USY@ZnO/Al₂O₃) as Efficient Lewis Acid Catalysts for Baeyer–Villiger Oxidation

Abstract

A ZnAl-LDHs (layered double hydroxides) phase was readily formed on the surface of a USY zeolite through a distinctive in situ growth method that benefitted from the interaction of the added Zn source and aluminum species extracted from the Al-rich USY zeolite crystals. The migration of aluminum and simultaneous interaction with the external Zn source took place in one pot to form a ZnAl-LDHs phase coated on the surface of the USY crystals. Upon calcination, the ZnAl-LDHs phase was transformed into a ZnO/Al O composite that was still firmly anchored on the USY zeolite, without sacrificing the core-shell structure. The resultant USY@ZnO/Al O materials gave rise to unique Lewis acidity and hierarchical porosity, which endowed the catalyst with promising performance in the Baeyer-Villiger oxidation of ketones with H O or bulky tert-butyl hydroxide as an oxidant.

Hydroxymethylfurfural (HMF) Synthesis from Starch with Zeolite Based Catalysts

“…Pore diameter distribution also support isotherm graphs with homogeneous mesoporous distribution. [27,29] Although the pores of all catalysts are distributed around 16-300 Å, the size density is around 37 Å.…”

One‐Pot Synthesized Nickel‐Doped Hierarchically Porous Beta Zeolite for Enhanced Methanol Electrocatalytic Oxidation Activity

“…[5] Recently, extensive attentions have been paid on the development of non-noble metal species because of their great potentials to replace precious metals in many catalytic processes. [3b,6] For example, controllably nano-confinement ZnO on ultrastable Y-type zeolites as efficient Lewis acid catalysts exhibited high performance for Bayer-villiger oxidation rearrangement reaction, [7] and PbÀ M(OH) 2 (M=Ni, Co) subnanometric clusters in zeolites showed high hydrogen generation performance. [8] Although great advantages of ultra-small sized metallic nanoparticles have been made in the field of catalysis, possible issues such as aggregation, poor hydrothermal stability and dissolution are usually inevitable during catalytic reaction.…”