In situ real time monitoring of Pt-VO2 nanoparticle-nanowire assembly by GISAXS

C. T. Yavuz*, S. Lee, B. Lee, M. H. Kim, J. M. Baik, C. Larson, S. Seifert, S. Vajda, R. E. Winans, M. Moskovits, G. D. Stucky, A. M. Wodtke
Proc. SPIE, Vol. 7679, 76792D (2010). [DOI] [pdf]

Methanol is a hydrogen carrier for fuel cells and its chemical transformations are of great current interest. Methanol oxidation by vanadium oxides is well studied, hence, serves as a good measure for catalytic activity. Arrays of VO₂ nanowires grown on r-cut sapphire prove to be unique for the in situ catalytic activity tests. Here, we present size and morphology dependent activity of Platinum coated single crystalline VO₂ nanowires in methanol oxidation reactions using Grazing Incidence Small Angle X-ray Scattering (GISAXS). Our findings show an unexpected sintering behavior of Pt at temperatures as low as 200 °C.

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Pollution Magnet: Nano Magnetite for Arsenic Removal from Drinking Water

C. T. Yavuz, J. T. Mayo, C. Suchecki, J. Wang, A. Z. Ellsworth, H. D’Couto, E. Quevedo, A. Prakash, L. Gonzalez, C. Nguyen, C. Kelty, V. L. Colvin*
Environ. Geochem. Health, 32, 327–334 (2010). [DOI] [pdf]

Arsenic contamination in groundwater is a severe global problem, most notably in Southeast Asia where millions suffer from acute and chronic arsenic poisoning. Removing arsenic from groundwater in impoverished rural or urban areas without electricity and with no manufacturing infrastructure remains a significant challenge. Magnetite nanocrystals have proven to be useful in arsenic remediation and could feasibly be synthesized by a thermal decomposition method that employs refluxing of FeOOH and oleic acid in 1-octadecene in a laboratory setup. To reduce the initial cost of production, $US 2600/kg, and make this nanomaterial widely available, we suggest that inexpensive and accessible “everyday” chemicals be used. Here we show that it is possible to create functional and high-quality nanocrystals using methods appropriate for manufacturing in diverse and minimal infrastructure, even those without electricity. We suggest that the transfer of this knowledge is best achieved using an open source concept.

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