Synthesis of large ETS-4 crystals in the Na and Na/K systems: the effects of alkali metal ion and synthesis mixture alkalinity

Morphology Changes of Transition-Metal-Substituted Aluminophosphate Molecular Sieve AlPO4-5 Crystals

“…In some cases, the crystal shape and size of zeolites can be manipulated by systematic variation of the synthetic parameters. For example, the aspect ratio ( b / c ) of mordenite crystals can be significantly reduced by increasing the alkalinity of the reaction system; the size and shape of ETS-4 crystals can be modified by varying pH and the Na/K ratio of the synthetic gel . In addition, the nature of structure-directing agents (SDAs) has been found to have influence on the morphology of zeolites .…”

Oriented Growth of ETS-4 Films Using the Method of Secondary Growth

“…Unlike bulk ETS-4, which under static conditions grows by the low-angle branching mechanism, 6,8,9 ETS-4 crystals in seed layers appeared to grow predominantly by epitaxy. Verification of the contribution of the branching mechanism to the film formation may be difficult, since branching in ETS-4 occurs at small angles to the b-direction.…”

“…As a result, these chains can behave as quantum wires. [6][7][8] Since the ...Ti-O-Ti-O-Ti... chains in ETS-4 crystals run in the [010] direction, 9 aligned crystals may provide oriented arrays of quantum wires. Thus, there is interest in growing b-out-of-plane oriented ETS-4 films (crystal b-directions preferentially oriented perpendicular to the substrate plane) in order to test the potential of ETS-4 crystals as quantum wire components of thermoelectric and photovoltaic devices.…”

“…ETS-4 is a microporous titanosilicate molecular sieve with a framework structure composed of [SiO 4 ] tetrahedra, [TiO 5 ] semioctahedra, and [TiO 6 ] octahedra. , The [TiO 6 ] octahedra are linked to form linear monatomic ...Ti−O−Ti−O−Ti... chains, which are isolated from one another by a siliceous matrix made of [SiO 4 ] tetrahedra. As a result, these chains can behave as quantum wires. − Since the ...Ti−O−Ti−O−Ti... chains in ETS-4 crystals run in the [010] direction, aligned crystals may provide oriented arrays of quantum wires. Thus, there is interest in growing b -out-of-plane oriented ETS-4 films (crystal b -directions preferentially oriented perpendicular to the substrate plane) in order to test the potential of ETS-4 crystals as quantum wire components of thermoelectric and photovoltaic devices.…”

Hydrothermal synthesis of SAPO-5 with novel morphologies from hydrogels containing acetic acid and high concentration of triethylamine under neutral or alkaline conditions

“…5 ETS-4 of spherulitic crystals that resemble two cauliflower heads attached to each other, formed by submicron crystallites and well-defined rectangular prisms with minimal intergrowth, are prepared by varying the initial pH and the Na/K ratio in the synthesis mixture. 6 Also, the synthesis of long zeolite-L crystals with flat basal and side facets is accomplished by using Al 2 (SO 4 ) 3 as the alumina source, and the size of the crystal can be significantly decreased (while the faceted crystal shape is retained) by adding inorganic additives such as LiCl and MgCl 2 in the reaction system. 7 Pseudocubic plate-like SAPO-34 crystals displaying BET surface areas up to 700 m 2 g À1 , enhanced CO 2 /CH 4 adsorption ratios, and crystal sizes in the 0.6-0.9 mm range with narrow particle size distribution are synthesized, employing polyethylene glycol, polyoxyethylene lauryl ether, and methylene blue as crystal growth inhibitors.…”