Applications of Thin Film Oxides in Catalysis
Metal oxides are fundamentally important as heterogeneous catalysts – either as stand-alone catalysts or in combination with other oxides and/or metals. In this chapter, we focus on how the use of thin film metal oxides, in lieu of bulk oxides, can potentially enhance catalytic activity. We illustrate this concept with two examples. In the first example, we discuss a molybdenum trioxide monolayered structure that can be grown on the gold (111) surface. In contrast to the bulk molybdenum trioxide that is composed of bilayers, this oxide monolayer is semimetallic and has distinct chemical properties. In the second example, we propose that ultrathin oxide layers can enable the coupling of structural distortions and charge transfer beyond that allowed in the bulk, and that ultrathin oxide supports can play a dynamic, active, role in promoting catalysis in supported metal catalysts.
KeywordsScanning Tunneling Microscopy Image Bulk Oxide Molybdenum Trioxide Charge Density Difference Herringbone Pattern
We gratefully acknowledge Prof. C.M. Friend for numerous discussions that have shaped our understanding of the systems discussed here, as part of a collaboration with her group. We are also indebted to several members of the Friend group for sharing with us experimental results and knowledge, including M.M. Biener and J. Biener for the STM images in Figs. 9.2 and 9.4a (originally published in Ref. ); X. Deng for valuable discussions; D.-H. Kang for the electron energy loss spectroscopy spectra discussed in Sect. 9.2 (originally published in Ref. ). Finally, we thank Prof. D.W. Goodman, B.K. Min, and M.-S. Chen for initial communications that motivated our work presented in Sect. 9.3 (originally published in Ref. [ 53]).
The present work was supported in part by the National Computational Science Alliance under DMR030044, and by the Harvard NNIN/C. SYQ acknowledges support from the Agency of Science, Technology and Research (Singapore), and current support from the Molecular Foundry by the Office of Science, Basic Energy Sciences, US Department of Energy under Contract No. DE-AC02–05CH11231.
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