Controlled release of siliceous species for the fabrication of highly b-oriented MFI zeolite films

Silicate precursor nanoparticles are complexed with 1,2-dihydroxybenzene and then gradually released to feed the secondary growth of b-oriented MFI zeolites.

Thermal processing of zeolite seed layers for the fabrication of compact oriented MFI zeolite films

The formation of a close-packed oriented MFI zeolite film through thermal processing created a strong covalent linkage between the seed layer and the substrate.

Fabrication of b-Oriented MFI Zeolite Films under Neutral Conditions without the Use of Hydrogen Fluoride

The fabrication of MFI zeolite films with particular b-axis orientation is especially fascinating. Unlike the conventional alkaline or hydrofluoric acid (HF) assisted neutral synthesis route, here we develop a novel neutral synthesis solution system of TPABr/fumed silica/H2 O without the use of HF and successfully synthesize highly b-oriented MFI zeolite films on glass-plate substrates by secondary growth. The localized weak alkaline environment created by the dissolved Na2 O species from the substrate is identified as the key factor for the depolymerization of fumed silica and subsequently the in-plane growth of zeolite seed layers. Continuous b-oriented MFI films can also be synthesized on other substrates in the presence of a glass plate or a trace amount of NaOH, which making our neutral synthesis route promising for the direct synthesis of MFI zeolite films and membranes on various substrates.

Gas sensing using porous materials for automotive applications

The use of zeolites and metal–organic frameworks in the sensing of gases emitted from automobile exhausts is reviewed.

The facile assembly of nanocrystals by optimizing humidity

Humidity and substrate properties are considered coordinately in the assembly of nano-sized crystals. The nanocrystal monolayers with thicknesses of 20–100 nm show large-area uniformity and excellent orientations.

Phase-segregation-induced self-assembly of anisotropic MFI microbuilding blocks into compact and highly b-oriented monolayers

A compact and highly b-oriented MFI monolayerwas fabricated with a novel phase-segregation-induced self-assembly method. When MFI microcrystals were dispersed uniformly in an appropriate dispersant (sec-butanol) containing a trace amount of binding agent (linoleic acid), these microbuilding blocks were spontaneously self-assembled into a compact monolayer at an air-liquid interface. In particular, it was observed that the binding agent took effect only after being phase-segregated from the aqueous solution. The influence of the kind of dispersants and binding agents on the final morphology of the as-prepared MFI monolayers was discussed. On the basis of these results, a mechanism was proposed to elucidate the driving force for the compact and oriented assembly of these MFI building blocks at the air-water interface.