Permeation of a Single-Layer SiO2 Membrane and Chemistry in Confined Space
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- 作者：Emre Emmez ; Bing Yang ; Shamil Shaikhutdinov ; Hans-Joachim Freund
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：December 18, 2014
- 年：2014
- 卷：118
- 期：50
- 页码：29034-29042
- 全文大小：519K
- ISSN：1932-7455
文摘
Well-ordered, ultrathin silica films grown on metal substrates are composed of layers of corner-sharing [SiO4] tetrahedra (silicatene). Yet unrealized in practice as unsupported material, the double-layer silicatene could constitute the thinnest silica membrane ever fabricated. We addressed here the permeability of such a membrane by using a metal substrate as a gas detector. Permeation of CO and D2 was examined by infrared reflection absorption spectroscopy and temperature-programmed desorption. The results reveal a complex response of such systems upon gas exposures which involves gas transport through amorphous silica pores as well as chemisorption and diffusion across the metal surface underneath the silicatene. Such a hybrid system, which would combine a robust molecular-sieve membrane and a chemically active metal underneath, could become interesting materials for technological applications, in particular, in catalysis and sensors.