AbstractsBiology & Animal Science

MONOLAYER NANOPOROUS FILMS

by Yun-Hao Hsieh




Institution: University of Manchester
Department:
Year: 2014
Keywords: 2D zeolite; Film
Record ID: 1398107
Full text PDF: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:232125


Abstract

Zeolites are well-known as porous crystalline solids with three-dimensional framework structure. However, after graphene was isolated by Novoselov et al. in 2004, two-dimensional materials start to attract much attention from researchers. There are three main synthesis methods to produce 2D layered zeolites: hydrothermal synthesis; surfactant-templated synthesis; partial zeolite hydrolysis. In this study, I tried to dissolve the linkages of ETAS-10 to get nano rods and use mechanical exfoliation to separate layered zeolites to monolayer.ETAS-10 has been reported that the highest Al/Ti molar ratio is 0.48. I used two different Ti sources and seeds to seek the best composition to make the Al/Ti molar ratio approach 1. The titanium chloride as Ti source can produce higher Al/Ti molar ratio than anatase. ETAS-10 as a seed in the 2nd step can decrease ETS-10 contents and increase Al/Ti molar ratio. Different seeds can make the ETAS-10 morphology different. The highest Al/Ti molar ratio in ETAS-10 reaches 0.652. The ETAS-10 samples were dissolved in different molar concentration hydrochloric acid to get nano rods. However, it transferred to form an unknown crystal that covered its surface.Three different layered zeolites which are UTL family, MWW family and lamellar MFI were exfoliated to monolayer by mechanical exfoliation. For UTL family, because of larger d-spacing, IPC-1SW was exfoliated to thinner flakes than IPC-1P and its thinnest flakes is about 1.21 ± 0.2 nm without any other obviously terraces. All of MWW family can be separated to monolayer which has 3.16 ± 0.2 nm height. The lamellar MFI got the largest area of thin flakes after mechanical exfoliation. The thinnest flakes of lamellar MFI we can find is 2.08 ± 0.2 nm. However, the mechanical exfoliation can not remove the template that remains in the monolayer to form another ultrathin layer. The MFI layers are the most interesting as they have nanopores running across the thin dimension.