Microporous Titanosilicates and other Novel Mixed Octahedral-Tetrahedral Framework Oxides

Abstract

Stable microporous materials, such as zeolites, are extremely important for applications in catalysis, adsorption, ion‐exchange, and separation. In this review we describe a new class of stable microporous materials that involves novel mixed octhaedral‐tetrahedral framework oxides. The archetypal material is based on titanosilicates, although there is tremendous scope for introducing many other transition metals. These materials not only have potential novel applications in the fields normally associated with zeolites but also possible applications in the areas of optoelectronics, nonlinear optics, batteries, magnetic materials and sensors.

A titanosilicate molecular sieve with adjustable pores for size-selective adsorption of molecules

“…As-synthesized ETS-4 has been reported to collapse near 200 8C to an amorphous material owing to the loss of structural water chains present along the channel system 15 . We found that carefully controlled heating leads to a monotonic decrease of the lattice dimensions in all three crystallographic directions, along with the gradual loss of crystallinity.…”

A rapid method of synthesizing the layered titanosilicate JDF-L1

“…Its structure contains titanosilicate layers built of small cage-type units, each one containing eight tetrahedral SiO 4 units and one square-pyramidal TiO 5 polyhedron. 6 This makes JDF-L1 a promising material for oxidation catalysis. 5 The JDF-L1 layered structure allows pillaring as demonstrated by the successful intercalation of nonylamine.…”

Introduction

“…This is the field of zeolites [31,123] and zeotypes [124,125] that are nanoporous crystalline systems constituted by corner-sharing [TO 4 ] tetrahedra (T ¼ Si, Al or P mainly) exhibiting pores of molecular dimension (0.5e1.5 nm range). This is the field of zeolites [31,123] and zeotypes [124,125] that are nanoporous crystalline systems constituted by corner-sharing [TO 4 ] tetrahedra (T ¼ Si, Al or P mainly) exhibiting pores of molecular dimension (0.5e1.5 nm range).…”