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Item type:Publication, Access status: without files , Nanoporous gold dealloyed from AuAg and AuCu: Comparison of structure and chemical composition© 2018 Properties of dealloyed nanoporous gold (npAu) in catalysis, sensing or actuation applications depend on its structure and chemical composition. NpAu is obtained by corrosion of alloys of gold and a less noble metal such as silver or copper. Structural parameters can be tuned by variations in the preparation process. Due to the large number of parameters that can be varied a direct comparison of results obtained with various samples is often difficult. In this report we compare structure and chemical composition of npAu dealloyed from AuAg and AuCu alloys keeping the number of different sample preparation parameters at a minimum.Publicationtype: Journal Article189 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Measurement of local crystal lattice strain variations in dealloyed nanoporous gold(Taylor & Francis, 2018-01-02); ; ; ; Reversible macroscopic length changes in nanoporous structures can be achieved by applying electric potentials or by exposing them to different gases or liquids. Thus, these materials are interesting candidates for applications as sensors or actuators. Macroscopic length changes originate from microscopic changes of crystal lattice parameters. In this report, we show spatially resolved measurements of crystal lattice strain in dealloyed nanoporous gold. The results confirm theory by indicating a compression of the lattice along the axis of cylindrically shaped ligaments and an expansion in radial direction. Furthermore, we show that curved npAu surfaces show inward relaxation of the surface layer. (Figure presented) IMPACT STATEMENT We show spatially resolved measurements of strain in nanoporous gold confirming theory: Crystal lattice is compressed along the axis of cylindrical ligaments and expanded in radial direction, surfaces relax inward.Publicationtype: Journal ArticleScopus© Citations 12 401 392 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A comparative study of alcohol oxidation over nanoporous gold in gas and liquid phase(Elsevier, 2017-08-02); ; ; ; The aerobic oxidation of methanol and ethanol in liquid phase is investigated using unsupported nanoporous gold (npAu) catalysts and compared to gas phase experiments. We pursue the question if this material is still suited as a type of model catalyst even under much more complex conditions in liquid phase. Indeed, npAu is an active catalyst for both liquid and gas phase oxidation of methanol and ethanol with O2 under mild conditions (starting at 40 °C). While in case of methanol solely the self coupling product (methyl formate) is detected, the more facile formation of the acetaldehyde in case of ethanol results in the formation of the free aldehyde (acetaldehyde) and the coupling product (ethyl acetate) in similar amounts. To further probe the surface chemistry, cross coupling reactions between both alcohols, as well as the acetaldehyde are performed. As observed also in gas phase experiments, the formation of the surface bonded aldehyde by β-H elimination of the alcoxy species is rate determining.Publicationtype: Journal Article207