TY - JOUR
T1 - Hydrothermal synthesis of oriented ETS-4 films on porous α-alumina substrates
AU - Shattuck, Kristin G.
AU - Yilmaz, Bilge
AU - Warzywoda, Juliusz
AU - Sacco, Albert
N1 - Funding Information:
The authors would like to acknowledge NASA for financial support.
PY - 2006/1/21
Y1 - 2006/1/21
N2 - Preparation of ETS-4 films on porous α-alumina substrates was investigated using gel-forming synthesis mixtures (3.6SiO2:1TiO 2:5.5Na2O:xH2SO4:230.2H 2O, x = 4.4 or x = 3.6). The procedure involved two steps: direct in situ hydrothermal crystallization of seed layers, followed by their secondary growth. ETS-4 seed layers (thickness ∼ 3.0-4.0 μm) were obtained using gels with x = 4.4 when the autoclaves were rotated (72 RPM). The seed layers consisted of submicron plate-like crystals and were partially b-out-of-plane oriented. Films, obtained in the second step under static synthesis conditions, had a columnar microstructure and were highly (x = 4.4) or less preferentially (x = 3.6) oriented (b-out-of-plane). This orientation is desirable for many applications of ETS-4 films. The observable dimensions of crystals in films increased more than twice from these in seed layers. Film thickness increased up to ∼10.0-11.0 μm. Incorporation of new crystals into the film was not detected. Thus, these films were obtained by direct, evolutionary growth of seed crystals. Secondary growth conditions that effectively decouple nucleation from growth of seeds, and provide the highest growth rate along the b-direction, were established for ETS-4.
AB - Preparation of ETS-4 films on porous α-alumina substrates was investigated using gel-forming synthesis mixtures (3.6SiO2:1TiO 2:5.5Na2O:xH2SO4:230.2H 2O, x = 4.4 or x = 3.6). The procedure involved two steps: direct in situ hydrothermal crystallization of seed layers, followed by their secondary growth. ETS-4 seed layers (thickness ∼ 3.0-4.0 μm) were obtained using gels with x = 4.4 when the autoclaves were rotated (72 RPM). The seed layers consisted of submicron plate-like crystals and were partially b-out-of-plane oriented. Films, obtained in the second step under static synthesis conditions, had a columnar microstructure and were highly (x = 4.4) or less preferentially (x = 3.6) oriented (b-out-of-plane). This orientation is desirable for many applications of ETS-4 films. The observable dimensions of crystals in films increased more than twice from these in seed layers. Film thickness increased up to ∼10.0-11.0 μm. Incorporation of new crystals into the film was not detected. Thus, these films were obtained by direct, evolutionary growth of seed crystals. Secondary growth conditions that effectively decouple nucleation from growth of seeds, and provide the highest growth rate along the b-direction, were established for ETS-4.
KW - ETS-4
KW - Molecular sieve films
KW - Quantum wires
KW - Synthesis
KW - Titanosilicates
UR - http://www.scopus.com/inward/record.url?scp=29244442585&partnerID=8YFLogxK
U2 - 10.1016/j.micromeso.2005.08.015
DO - 10.1016/j.micromeso.2005.08.015
M3 - Article
AN - SCOPUS:29244442585
SN - 1387-1811
VL - 88
SP - 56
EP - 62
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
IS - 1-3
ER -