Hydrogele und Aerogele aus Edelmetallnanopartikeln

Abstract

Trägerfreie makroskopische Aerogele wurden aus Platin‐, Gold‐ und Silber‐ sowie aus gemischten Gold‐Silber‐ und Platin‐Silber‐Nanoteilchenlösungen hergestellt. Die Hydro‐ und Aerogele sind voluminöse poröse Netzwerke, die sich aus Partikeln oder Drähten mit wenigen Nanometern Dicke zusammensetzen. Diese neuartigen Strukturen verfügen über ein enormes Anwendungspotenzial in der Katalyse und Nanophotonik.

Redox Sorption and Recovery of Silver Ions as Silver Nanocrystals on Poly(aniline‐co‐5‐sulfo‐2‐anisidine) Nanosorbents

“…[21] In other words, the AN/SA (50/50) copolymer nanograins are very strong Hg-ion nanosorbents and ultrastrong Ag I nanosorbents. At the same time, a unique hybrid Ag nanocrystal/copolymer nanograin nanocomposite with widely controllable electrical conductivity and potential application as electrode modifier due to its high catalytic activity [7] was facilely obtained as the result of Ag I sorption. To sum up, the AN/SA (50/50) copolymer nanograins carrying numerous functional groups on their porous and rough structure are not only outstanding Ag I sorbents with a bright future for removal and recovery of noble Ag I from typical wastewaters, but also novel multifunctional materials having excellent redox reactivity, intrinsic electrical conductivity, high environmental stability, and practical recoverability of Ag as Ag nanocrystals.…”

“…[7] Compared with early inefficient methods, modern techniques for silver recovery from scrap and wastewaters such as photographic films, X-ray films, and jewelry are highly efficient, and include sorption, precipitation, ion exchange, reductive exchange, and electrolysis. Some modern sorbents, such as polymers, [8][9][10][11] chitosan, [12][13] carbonaceous materials, [14] coal, [15] and layered sulfides, [16] have already exhibited very good performance for recovery of noble and heavy metals.…”

“…Polyaniline microparticles have strong Ag I adsorption/reducibility, but the AN/SA (50/50) copolymer nanograins have even stronger Ag I adsorption capability/reducibility, indicating that the nanograins are powerful Ag I nanosorbents and hybrid Ag nanocrystal/copolymer nanograin nanocomposites with potential application as electrode modifiers due to their high catalytic activity. [7] Apparently, this significantly www.chemeurj.org improved adsorbability is attributable to the rough-surface nanostructures, on which the methoxyl and sulfo groups containing oxygen and sulfur atoms offer more lone-pair electrons that can spontaneously attract electron-poor heavymetal ions. Notably, the water solubility of the nanograins gradually becomes stronger at a feed SA content higher than 50 mol % because of their inherent hydrophilicity due to more sulfo groups, which consequently leads to slightly reduced adsorbability.…”

Alloying Behavior of Self‐Assembled Noble Metal Nanoparticles

“…Multimetallic aerogels can be easily obtained by self‐assembly of monometallic nanoparticles during the gelation process . First, each metal precursor is reduced in separate pots to form monometallic nanoparticles.…”

Anordnung von BaTiO3‐Nanokristallen zu makroskopischen Aerogelmonolithen mit großer Oberfläche

“…Ungeachtet des erheblichen Aufwandes, dieses Konzept auf vorgefertigte nanokristalline Bausteine anderer Materialien zu erweitern, blieb die Zusammensetzung auf Metallchalkogenide, [9] Edelmetalle [10] und deren Kombination beschränkt.[11] Basierend auf der Beobachtung, dass die Destabilisierung von Oberflächen-funktionalisierten Titandioxidnanopartikeln zu orientierter Anlagerung in einer bevorzugten Richtung über mehrere Grçßenordnungen führt, [12] …”