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Item type:Publication, Access status: with files , Nanoporous Gold: from structure evolution to functional properties in catalysis and electrochemistry(2023-05-24); ; ; Nanoporous gold (NPG) is characterized by a bicontinuous network of nanometer-sized metallic struts and interconnected pores formed spontaneously by oxidative dissolution of the less noble element from gold alloys. The resulting material exhibits decent catalytic activity for low-temperature, aerobic total as well as partial oxidation reactions, the oxidative coupling of methanol to methyl formate being the prototypical example. This review not only provides a critical discussion of ways to tune the morphology and composition of this material and its implication for catalysis and electrocatalysis, but will also exemplarily review the current mechanistic understanding of the partial oxidation of methanol using information from quantum chemical studies, model studies on single-crystal surfaces, gas phase catalysis, aerobic liquid phase oxidation, and electrocatalysis. In this respect, a particular focus will be on mechanistic aspects not well understood, yet. Apart from the mechanistic aspects of catalysis, best practice examples with respect to material preparation and characterization will be discussed. These can improve the reproducibility of the materials property such as the catalytic activity and selectivity as well as the scope of reactions being identified as the main challenges for a broader application of NPG in target-oriented organic synthesis.Publicationtype: Review ArticleScopus© Citations 26 40 54 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , How silver segregation stabilizes 1D surface gold oxide: A cluster expansion study combined with: Ab initio MD simulations(2017-05-09); ; ; Gold has many unique properties, some of which continue to be uncovered, such as the rich chemistry of gold at the nanoscale. In this study, gold surprises us again by the unusual stability of one-dimensional gold oxide structures on the surface of gold, which enhances in the presence of silver impurities. We employ first-principles calculations to investigate the surface segregation of silver in the presence of atomic-oxygen adsorbates arranged in chains on the Au(321) surface. Such 1D oxide chains have previously been suggested as the most stable form of adsorbed oxygen on gold. Although Ag-O bonds are expected to be generally stronger than Au-O bonds, we show that this does not hold for 1D oxide chains, where Au-O bonds seem to be at least as strong as Ag-O bonds. Remarkably, we find that up to very high surface concentrations of silver, the Ag atoms do not occupy positions within the oxide chain, but prefer locations next to it. Ab initio molecular dynamics simulations support this picture and reveal how oxide chains and silver atoms rearrange on the surface toward a lower-energy configuration.Publicationtype: Journal Article134