Sophie Carenco, Cheng-Hao Wu, Andrey Shavorskiy, Selim Alayoglu, Gabor A Somorjai, Hendrik Bluhm, Miquel Salmeron
文献索引：Small 11 , 3045-53, (2015)
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Bimetallic nanoparticle (NP) catalysts are interesting for the development of selective catalysts in reactions such as the reduction of CO2 by H2 to form hydrocarbons. Here the synthesis of Ni-Co NPs is studied, and the morphological and structural changes resulting from their activation (via oxidation/reduction cycles), and from their operation under reaction conditions, are presented. Using ambient-pressure X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and transmission electron microscopy, it is found that the initial core-shell structure evolves to form a surface alloy due to nickel migration from the core. Interestingly, the core consists of a Ni-rich single crystal and a void with sharp interfaces. Residual phosphorous species, coming from the ligands used for synthesis, are found initially concentrated in the NP core, which later diffuse to the surface.© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
