Silanol defect engineering and healing in zeolites: opportunities to fine-tune their properties and performances

Abstract

The main approaches for engineering and healing of defects in zeolites known for their iconic shape-selective properties widely explored in key areas such as catalysis, waste management, gas separation and biomedicine are revealed.

Hydronium ion and water complexes vs. methanol on solid catalyst surfaces: how confinement influences stability and reactivity

“…Such groups are often associated with defects in crystalline zeolite catalysts and impact the catalytic properties. 32,33 The confinement of water in mesoporous materials like MCM-41 and SBA-15 was investigated by Grünberg et al 34 by means of 1 H MAS NMR spectroscopy and the pore diameter (respectively confinement) impacted the way of hydration. The sites of water adsorption in such mesoporous SBA-15 are preferentially SiIJOH) 2 groups.…”

The challenge of silanol species characterization in zeolites

“…All of these pro-perties in turn influence the nature and number of the silanol species present in the corresponding zeolites, and their hydrophobicity and catalytic properties. 8 A non-exhaustive list of silanol features in zeolites is:…”

Recent advances in solid-state NMR of zeolite catalysts

“…various types of silanols) are generated during the synthesis or post-treatment. The zeolite defect is one of the decisive parameters affecting zeolite properties including hydrophilicity/hydrophobicity, stability and catalytic activity [ 64 , 65 ]. Besides, the defects in zeolites can act as anchoring positions for the incorporation of different heteroatoms (Mo, V, B, etc.)…”