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Morphological and surface analysis of titanosilicate ETS-4 synthesized hydrothermally with organic precursors

2004; Elsevier BV; Volume: 69; Issue: 1-2 Linguagem: Inglês

10.1016/j.micromeso.2003.12.020

1873-3093

P.Q. Miraglia, Bilge Yilmaz, Juliusz Warzywoda, S. Bazzana, Albert Sacco,

Crystal Structures and Properties

Morphological and surface analysis was performed on titanosilicate ETS-4 crystals using atomic force microscopy (AFM) and field emission scanning electron microscopy. Crystals were synthesized hydrothermally at 175 °C in Teflon-lined stainless steel autoclaves using organic precursors. Rectangular and plate shaped crystals were formed with the largest crystals being 2 × 20 × 5 μm and 2 × 10 × 10 μm, respectively. EDX analysis revealed a disparity between the Si/Ti ratio in crystals characterized by different morphologies (2.5 for rectangular vs. 2.8 for plates). Growth occurred on the slowest growing and the largest crystal via a layer mechanism. Spiral hillocks were found on {1 0 0} surfaces of rectangular shaped crystals and on the largest faces of intergrown plate crystallites. Steps on these surfaces were observed to emanate from spiral hillocks and had a step height of 1.10 ± 0.15 nm. The crystallographic d-spacing of the (2 0 0) plane, as measured by powder X-ray diffraction, correlated with the AFM measured step height.