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Noble metal
About: Noble metal is a research topic. Over the lifetime, 15113 publications have been published within this topic receiving 337947 citations.
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TL;DR: In this paper, a cubic phased nanospheres of approximately 20-30nm in diameter are comprised of nanocrystals of about 5-nm, which are enriched with Zn and Cu sulfide layers.
98 citations
TL;DR: In this paper, a single step chemical route was described to embed the silver and gold nanoparticles in composite films and the embedded composite films were characterized with, UV-vis, TEM and XPS analysis.
98 citations
TL;DR: Human H ferritin was redesigned to facilitate noble metal ion (Au(3+), Ag(+)) binding, reduction, and nanoparticle formation within the cavity.
Abstract: Human H ferritin (HuHF) assembles from 24 four-helix bundles to form an approximately 500 kDa protein with an 8 nm internal cavity. HuHF provides a useful model for studying the transport of metal ions in solution to buried reaction sites in proteins. In this study, HuHF was redesigned to facilitate noble metal ion (Au(3+), Ag(+)) binding, reduction, and nanoparticle formation within the cavity. Computationally determined amino acid substitutions were targeted at four external and four internal surface sites. A variant with a total of 96 cysteines and histidines removed from the exterior surface and 96 non-native cysteines added to the interior surface retained wild-type stability and structure, as confirmed by X-ray crystallography, and promoted the formation of silver or gold nanoparticles within the protein cavity. Crystallographic studies with HuHF variants provide insight into how ferritins control access of metal ions to interior residues that perform chemistry.
98 citations
TL;DR: In this paper, a ruthenium nanoparticles supported on magnesia is proposed to promote heterolytic hydrogen splitting and surface ionic hydrogenation pathways, which may have interesting implications for the development of new poison-tolerant noble metal catalytic systems.
98 citations
TL;DR: PdAu/TiO-ZrO 80/20 catalysts demonstrated the best activity and life span in the oxidation of toluene and propene and offered the lowest temperatures for a 50 % conversion of VOCs and the lowest coke content after catalytic testing.
Abstract: The use of porous materials to eliminate volatile organic compounds (VOCs) has proven very effective towards achieving sustainability and environmental protection goals. The activity of zeolites and macro-mesoporous metal-oxide supports in the total oxidation of VOCs has been investigated, with and without noble-metal deposition, to develop highly active catalyst systems where the formation of by-products was minimal. The first catalysts employed were zeolites, which offered a good activity in the oxidation of VOCs, but were rapidly deactivated by coke deposition. The effects of the acido-basicity and ionic exchange of these zeolites showed that a higher basicity was related to exchanged ions with lower electronegativities, resulting in better catalytic performances in the elimination of VOCs. Following on from this work, noble metals were deposited onto macro-mesoporous metal-oxide supports to form mono and bimetallic catalysts. These were then tested in the oxidation of toluene to study their catalytic performance and their deactivation process. PdAu/TiO(2) and PdAu/TiO(2) -ZrO(2) 80/20 catalysts demonstrated the best activity and life span in the oxidation of toluene and propene and offered the lowest temperatures for a 50 % conversion of VOCs and the lowest coke content after catalytic testing. Different characterization techniques were employed to explain the changes occurring in catalyst structure during the oxidation of toluene and propene.
98 citations