(158d) Successive Ionic Layer Deposition of Barium Oxide On Fused Aluminum Oxide Powders | AIChE

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(158d) Successive Ionic Layer Deposition of Barium Oxide On Fused Aluminum Oxide Powders

Authors 

Gilbert, T. I. - Presenter, University of Michigan
Schwank, J. - Presenter, University of Michigan


The complexity of typical supported catalyst systems makes it difficult to isolate the effects of metal-support interactions. Successive ionic layer deposition (SILD) is a technique which enables the synthesis of well-defined multilayer catalytic systems. In SILD, submonolayers of desired cations and anions are alternately and selectively adsorbed on a support to produce SILD nanoislands or nanolayers with controlled composition and morphology.

Several recent studies suggest that a highly dispersed phase of barium oxide supported on g-alumina is a better catalyst for NOx storage in lean burn engine emissions than a bulk-like phase of supported barium oxide [1-4].

We have shown previously that SILD is capable of depositing dispersed nanoislands of barium oxide (diameter ~ 15 nm, height ~ 1 to 2 nm) on model aluminum oxide surfaces [5]. This work describes how SILD was used to create a dispersed phase of barium oxide on fused aluminum oxide powders of higher surface area than the previous model supports. Fused aluminum oxide powder, consisting of aggregated crystalline Al2O3 particles approximately 120 nm in diameter with a total BET surface area of 6.6 m2/gram, was used as the support for the SILD of barium oxide. The presence of BaO on the fused-Al2O3 surface was confirmed by XPS. Surface nitrates were formed by flowing NO2 as the samples cooled from 500oC to room temperature. Nitrate decomposition was then analyzed using an integrated TGA/FT-IR system. The NO2 storage behavior of the BaO/Al2O3 was also characterized by in-situ Diffuse Reflectance IR Fourier-Transform Spectroscopy (DRIFTS).

REFERENCES

1. X Chen, J Schwank, J Li, WF Schneider, CT Goralski, Jr., PJ Schmitz. Appl. Catal. B 61, 164-175 (2005).

2. X Chen, J Schwank, J Li, WF Schneider, CT Goralski, Jr., PJ Schmitz. J. Mater. Chem. 15, 366-368 (2005).

3. J Szanyi, JH Kwak, DH Kim, SD Burton, CHF Peden. J. Phys. Chem. B 109, 27-29 (2005).

4. JH Kwak, D Mei, C-W Yi, DH Kim, CHF Peden, LF Allard, J Szanyi. J. Catal. 261, 17-22 (2009).

5. T Gilbert, J Schwank. submitted (2009).

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