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nano catalysis

Natalia Martín Sabanés, Katrin F Domke
Electrochemistry is re-gaining attention among scientists because the complex interplay between electronic and chemical interfacial processes lies at the bottom of a broad range of important research disciplines like alternative energy conversion or green catalysis and synthesis. While rapid progress has been made in recent years regarding novel technological applications, the community increasingly recognizes that the understanding of the molecular processes that govern macroscopic device properties is still rather limited - which hinders a systematic and more complete exploration of novel material and functionality space...
August 2017: ChemElectroChem
Fabian Itel, Philipp S Schattling, Yan Zhang, Brigitte Städler
Cell mimicry is a nature inspired concept that aims to substitute for missing or lost (sub)cellular function. This review focuses on the latest advancements in the use of enzymes in cell mimicry for encapsulated catalysis and artificial motility in synthetic bottom-up assemblies with emphasis on the biological response in cell culture or more rarely in animal models. Entities across the length scale from nano-sized enzyme mimics, sub-micron sized artificial organelles and self-propelled particles (swimmers) to micron-sized artificial cells are discussed...
September 12, 2017: Advanced Drug Delivery Reviews
A Poma, A Forni, C Baldoli, P R Mussini, A Bossi
Square planar platinum complexes are an important class of compounds used in (nano)technology, optoelectronics, medicinal chemistry and catalysis. The major research interests in cyclometalated Pt(ii) complexes focus on the selective modulation of their electronic properties and the control of the (cis/trans) geometry. For the first time, we unveil and demonstrate that cis-trans isomers of Pt(ii) complexes can be obtained in a derivative carrying the 1-phenyl-pirazolate (Hppz) and 2-hydroxy-1-naphtyl-(N-phenyl)imine ligands...
September 13, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Sofia Marchesini, Catriona M McGilvery, Josh Bailey, Camille Petit
Production of biocompatible and stable porous materials, e.g., boron nitride, exhibiting tunable and enhanced porosity is a prerequisite if they are to be employed to address challenges such as drug delivery, molecular separations, or catalysis. However, there is currently very limited understanding of the formation mechanisms of porous boron nitride and the parameters controlling its porosity, which ultimately prevents exploiting the material's full potential. Herein, we produce boron nitride with high and tunable surface area and micro/mesoporosity via a facile template-free method using multiple readily available N-containing precursors with different thermal decomposition patterns...
September 18, 2017: ACS Nano
Martin Spitzbarth, Andreas Scherer, Andreas Schachtschneider, Peter Imming, Sebastian Polarz, Malte Drescher
Diffusion in porous materials is under ongoing active investigation due to its major role in practical applications such as catalysis and chromatography. The complexity of these systems limits the use of the Einstein-Stokes diffusion theory, and it must be distinguished between the microscopic scale of diffusion at a molecular level, which is sensitive to the local surroundings of a diffusing molecule, and the macroscopic scale which takes into account diffusion spanning multiple pores, grain boundaries and inhomogeneity within the material...
August 31, 2017: Journal of Magnetic Resonance
Julien Ramade, Cyril Langlois, Michel Pellarin, Laurent Piccolo, Marie-Ange Lebeault, Thierry Epicier, Mimoun Aouine, Emmanuel Cottancin
Multimetallic nano-alloys display a structure and consequently physicochemical properties evolving in a reactive environment. Following and understanding this evolution is therefore crucial for future applications in gas sensing and heterogeneous catalysis. In view hereof, the structural evolution of oxidized Ag25In75 bimetallic nanoparticles under varying H2 partial pressures (PH2) and substrate temperatures (Ts) has been investigated in real-time through environmental transmission microscopy (E-TEM) while maintaining the atomic resolution...
September 6, 2017: Nanoscale
Hua Wang, Liefeng Liang, Xinjian Cheng, Yanmei Luo, Sheng Sun
Porous ZnS and ZnO nano-crystal films were fabricated via a three-step procedure. First, Zn(CH3 COO)2 /Silk Fibroin nanofiber mats were prepared by coaxial electrospinning. Second, Zn(CH3 COO)2 /Silk Fibroin mats were immersed in NaS solution to react with S(2-) to obtain ZnS/Silk Fibroin nanofiber mats. Finally, ZnO porous films were prepared by calcination of ZnS/Silk Fibroin composite mat at 600°C in air atmosphere. When ZnS/Silk Fibroin mats were calcinated in nitrogen, ZnS/Carbon composite mats were obtained accordingly...
August 31, 2017: Photochemistry and Photobiology
Hans-Joachim Freund, Wolf-Dieter Schneider, Markus Heyde
In chemistry and physics the electronic charge on a species or material is one important determinant of its properties. In the present review the essential requirements for a model catalyst system suitable to study charge control are discussed. The ideal model catalyst for this purpose consists of a material system, which comprises a single crystal metal support, covered by an epitaxially grown ultrathin oxide film, and flat, two-dimensional nano-particles residing on this film. Several examples from the published literature are selected and presented, which illustrate various aspects of electron transport from the support to the nanoparticle and vice versa...
August 31, 2017: Chemistry: a European Journal
Christoph Edlinger, Tomaz Einfalt, Mariana Spulber, Anja Car, Wolfgang Meier, Cornelia G Palivan
We describe an innovative strategy to generate catalytic compartments with triggered functionality at the nanoscale level by combining pH-reversible biovalves and enzyme-loaded synthetic compartments. The biovalve has been engineered by the attachment of stimuli-responsive peptides to a genetically modified channel porin, enabling a reversible change of the molecular flow through the pores of the porin in response to a pH change in the local environment. The biovalve functionality triggers the reaction inside the cavity of the enzyme-loaded compartments by switching the in situ activity of the enzymes on/off based on a reversible change of the permeability of the membrane, which blocks or allows the passage of substrates and products...
September 13, 2017: Nano Letters
T Jane Stockmann, Léo Angelé, Vitor Brasiliense, Catherine Combellas, Frédéric Kanoufi
Single nanoparticle (NP) electrochemistry detection at a micro liquid|liquid interface (LLI) is exploited through the oxygen reduction reaction (ORR) catalysis. In this way, current spikes reminiscent of nano-impacts were recorded owing to electrocatalytic enhancement of the ORR by Pt-NPs. The nature of the LLI provides the exploration of new phenomena in single NP electrochemistry. First, the current impacts are due to a bipolar reaction occurring at the Pt-NP straddling the LLI: O2 reduction takes place in the aqueous phase, while ferrocene hydride (Fc-H+), a complex generated upon facilitated interfacial proton transfer by Fc, is oxidized in the organic phase...
August 24, 2017: Angewandte Chemie
Zachary S Fishman, Yulian He, Ke R Yang, Amanda W Lounsbury, Junqing Zhu, Thanh Minh Tran, Julie B Zimmerman, Victor S Batista, Lisa D Pfefferle
Understanding how nano-dimensionality impacts iron oxide based catalysis is central to a wide range of applications. Here, we focus on hematite nanosheets, nanowires and nanoparticles as applied to catalyze the reverse water gas shift (RWGS) probe reaction. We introduce a novel approach to synthesize ultrathin (4-7 nm) hematite nanosheets using copper oxide nanosheets as a hard template and propose a reaction mechanism based on density functional theory (DFT) calculations. Hematite nanowires and nanoparticles were also synthesized and characterized...
September 14, 2017: Nanoscale
Shuang Jiang, Mahshid Chekini, Zhi-Bei Qu, Yichun Wang, Aydan Yeltik, Yuangang Liu, Alex Kotlyar, Tianyong Zhang, Bin Li, Hilmi Volkan Demir, Nicholas A Kotov
The chirality of nanoparticles (NPs) and their assemblies has been investigated predominantly for noble metals and II-VI semiconductors. However, ceramic NPs represent the majority of nanoscale materials in Nature. The robustness and other innate properties of ceramics offer technological opportunities in catalysis, biomedical sciences, and optics. Here we report the preparation of chiral ceramic NPs, as represented by tungsten oxide hydrate, WO3-x·H2O, dispersed in ethanol. The chirality of the metal oxide core, with an average size of ca 1...
August 12, 2017: Journal of the American Chemical Society
Vishal J Mayani, Suranjana V Mayani, Sang Wook Kim
Up to now, a very few catalysts have been developed approaching the heterogeneous catalytic degradation of Eosin Y and Chromotrope 2R dyes (Acid Red 29). The present study provides a complete perspective of recyclable nanocomposite Au(Salen)@CC for catalytic degradation of hazardous water pollutant dyes viz., Eosin Y & Chromotrope 2R using mild reaction conditions. New gold Salen complex doped carbon nanocomposite Au(Salen)@CC was developed by easy methodology using nano carbon cage (CC) prepared from low-priced Pyrolysis fuel oil (PFO) residue based Pitch...
August 3, 2017: Scientific Reports
Davit Jishkariani, Yaoting Wu, Da Wang, Yang Liu, Alfons van Blaaderen, Christopher B Murray
Janus nanoparticles (NPs) often referred to as nanosized analogs of molecular surfactants are amphiphilic structures with potential applications in materials science, biomedicine, and catalysis, and their synthesis and self-assembly into complex architectures remain challenging. Here, we demonstrate the preparation of Janus heterodimers via asymmetric functionalization of Fe3O4-Pt and Fe3O4-Au heterodimeric NPs. The hydrophobic and hydrophilic dendritic ligands that carry phosphonic acid and disulfide surface binding groups selectively coat the iron oxide and platinum (or gold) parts of the heterodimer, respectively...
August 22, 2017: ACS Nano
Siyuan Li, Haiyan Chen, Jie Liu, Yida Deng, Xiaopeng Han, Wenbin Hu, Cheng Zhong
Pulse potential electrodeposition was successfully utilized to electrochemically fabricate platinum (Pt) nanoparticles on indium tin oxide (ITO) conductive glass substrates for catalysis toward ammonia electro-oxidation. The effect of deposition parameters (lower potential El, lower potential duration tl, and upper potential duration tu) on the size and number density of Pt nanoparticles was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrocatalytic activity of the Pt nanoparticle/ITO electrode for ammonia oxidation was characterized by the cyclic voltammetry (CV) method...
August 11, 2017: ACS Applied Materials & Interfaces
S P Schwaminger, S A Blank-Shim, I Scheifele, P Fraga-García, S Berensmeier
Magnetic metal oxide nanoparticles demonstrate great applicability in several fields such as biotechnology, medicine and catalysis. A stable, magnetic and low-cost material, nanoscale magnetite, is an interesting adsorbent for protein purification. Downstream processing can account for up to 80% of the total production costs in biotechnological production. As such, the development of new innovative separation methods can be regarded as highly profitable. While short peptide sequences can be used as specific affinity tags for functionalised adsorber surfaces, they need expensive affinity ligands on the particle surface for adsorption...
August 2, 2017: Faraday Discussions
Jean-Nicolas Tisserant, Tino Wagner, Patrick A Reissner, Hannes Beyer, Yuriy Fedoryshyn, Andreas Stemmer
Carbon materials promise a revolution in optoelectronics, medical applications, and sensing provided that their morphology can be controlled down to the nanometer scale. Nanoporous materials are particularly appealing as they offer a drastically enlarged interfacial area compared to the corresponding planar materials. Entire fields such as organic solar cells, catalysis, or sensing may profit from an enlarged interface and facilitated molecular interaction between a carbon material and the environment. Nanoporous fullerene thin films obtained by the deposition of suspended nanoclusters of fullerene were already reported but suffered from the limitation of the size of these particles to over 100 nm...
August 16, 2017: ACS Applied Materials & Interfaces
Archana Samanta, Sonam Takkar, Ritu Kulshreshtha, Bhanu Nandan, Rajiv K Srivastava
Functionalized matrices have been sought for their application in sensors, filtration, energy storage, catalysis, and tissue engineering. We report formation of an inorganic-organic composite matrix based on poly(ε-caprolactone) (PCL) functionalized with hydrophobically modified silica (m-silica) fabricated with reduced organic solvent usage. The matrix was obtained via electrospinning of a water-in-oil emulsion of PCL that was stabilized by judicious choice of m-silica as a Pickering agent resulting into an emulsifier free matrix...
August 4, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Ganapathy Ranjani, Rajagopal Nagarajan
A ligand-free copper catalyzed Suzuki-Miyaura coupling of 3,5-diiodopyridine with aryl and indole boronates has been explored in good to excellent yields. In situ generation of nano-Cu2O from CuCl2 under the reaction conditions has been discovered for the first time. The generality of the reaction was further demonstrated by the arylation of 5-iodopyrimidine, iodopyridines, iodobenzenes, and diiodobenzenes and resulted in good to moderate yields. Moreover, bisindole alkaloid Scalaridine A has been successfully synthesized in 60% overall yield...
July 19, 2017: Organic Letters
Mouhong Lin, Gyeong-Hwan Kim, Jae-Ho Kim, Jeong-Wook Oh, Jwa-Min Nam
Multicomponent nanoparticles that incorporate multiple nanocrystal domains into a single particle represent an important class of material with highly tailorable structures and properties. The controlled synthesis of multicomponent NPs with 3 or more components in the desired structure, particularly anisotropic structure, and property is, however, challenging. Here, we developed a polymer and galvanic replacement reaction-based transformative heterointerface evolution (THE) method to form and tune gold-copper-silver multimetallic anisotropic nanoparticles (MAPs) with well-defined configurations, including structural order, particle and junction geometry, giving rise to extraordinarily high tunability in the structural design, synthesis and optical property of trimetallic plasmonic nanoantenna structures...
July 25, 2017: Journal of the American Chemical Society
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