Aerosol-Derived Bimetallic Alloy Powders: Bridging the Gap

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• 作者：Barr Halevi ; Eric J. Peterson ; Andrew DeLaRiva ; Ese Jeroro ; Vanessa M. Lebarbier ; Yong Wang ; John M. Vohs ; Boris Kiefer ; Edward Kunkes ; Michael Havecker ; Malte Behrens ; Robert Schlgl ; Abhaya K. Datye
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：October 14, 2010
• 年：2010
• 卷：114
• 期：40
• 页码：17181-17190
• 全文大小：544K
• 年卷期：v.114,no.40(October 14, 2010)
• ISSN：1932-7455

文摘

We present aerosol-derived alloy powders as a uniquely useful platform for studying the contribution of the metal phase to multifunctional supported catalysts. Multimetallic heterogeneous catalysts made by traditional methods are usually nonhomogenous while UHV-based methods, such as mass selected clusters or metal vapor deposited on single crystals, lead to considerably more homogeneous, well-defined samples. However, these well-defined samples have low surface areas and do not lend themselves to catalytic activity tests in flow reactors under industrially relevant conditions. Bimetallic alloy powders derived by aerosol synthesis are homogeneous and single phase and can have surface areas ranging 1−10 m²/g, making them suitable for use in conventional flow reactors. The utility of aerosol-derived alloy powders as model catalysts is illustrated through the synthesis of single phase PdZn which was used to derive the specific reactivity of the L1₀ tetragonal alloy phase for methanol steam reforming. Turnover frequencies on unsupported PdZn were determined from the experimentally determined metal surface area to be 0.21 molecules of methanol reacted per surface Pd at 250 °C and 0.06 molecules of CO oxidized to CO₂ per surface Pd at 185 °C. The experimentally measured activation energies for MSR and CO-oxidation on PdZn are 48 and 87 kJ/mol, respectively.