Complex solid solution electrocatalysts (often called high-entropy alloys) present a new catalyst class with highly promising features due to the interplay of multi-element active sites. One hurdle is the limited knowledge about structure-activity correlations needed for targeted catalyst design. We prepared Cr-Mn-Fe-Co-Ni nanoparticles by magnetron sputtering a high entropy Cantor alloy target simultaneously into an ionic liquid library.
View Article and Find Full Text PDFBottom-up and top-down approaches are described for the challenging synthesis of Fe/Al nanoparticles (NPs) in ionic liquids (ILs) under mild conditions. The crystalline phase and morphology of the metal nanoparticles synthesized in three different ionic liquids were identified by powder X-ray diffractometry (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected-area electron diffraction (SAED) and fast Fourier transform (FFT) of high-resolution TEM images. Characterization was completed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) for the analysis of the element composition of the whole sample consisting of the NPs and the amorphous background.
View Article and Find Full Text PDFComplex solid-solution electrocatalysts (also referred to as high-entropy alloy) are gaining increasing interest owing to their promising properties which were only recently discovered. With the capability of forming complex single-phase solid solutions from five or more constituents, they offer unique capabilities of fine-tuning adsorption energies. However, the elemental complexity within the crystal structure and its effect on electrocatalytic properties is poorly understood.
View Article and Find Full Text PDFThe development of antibacterial implant surfaces is a challenging task in biomaterial research. We fabricated a highly antibacterial bimetallic platinum (Pt)/silver(Ag) nanopatch surface by short time sputtering of Pt and Ag on titanium. The sputter process led to a patch-like distribution with crystalline areas in the nanometer-size range (1.
View Article and Find Full Text PDFBinary alloy nanoparticles were fabricated by two combinatorial methods: (I) from elemental targets into the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [Bmim][(Tf)N] and (II) by elemental nanoparticles after sputtering them separately into [Bmim][(Tf)N]. Both methods lead to the formation of Au-Cu nanoparticles (2.3 nm for cosputtered, 3.
View Article and Find Full Text PDFControlling the amorphous or crystalline state of multinary Cr-Mn-Fe-Co-Ni alloy nanoparticles with sizes in the range between ~1.7 nm and ~4.8 nm is achieved using three processing routes.
View Article and Find Full Text PDFA high-throughput method is presented for the efficient assessment of the formation and stability of nanoparticle suspensions in ionic liquids which differ in their cations and anions. As a proof of principle, Ag was sputtered on a cavity array filled with 9 different ionic liquids. Not all nanoparticle ionic liquid combinations form a stable suspension with separated nanoparticles.
View Article and Find Full Text PDFThe biomedical application of cerium oxide nanoparticles (nanoceria) is a focal point of research for a few years. The biochemical effects of nanoceria depend on various factors including particle size, oxidation state of cerium, oxygen vacancies on the surface, use of dispersants or coatings, pH and cell type. Due to their autocatalytic redox-activity, these particles are considered to act as a specific anti-cancer tool with less side effects on healthy cells and tissues, as the particles kill tumor cells, while protecting healthy cells from oxidative damage.
View Article and Find Full Text PDFOxime-based CO-releasing molecules (oximeCORMs) were immobilized with a catechol-modified backbone on maghemite iron oxide nanoparticles (IONPs) to give oximeCORM@IONP. The CO release from the free and immobilized oximeCORMs was measured using the standard myoglobin assay. The oximeCORM-nanoparticles were coated with dextran for improved water solubility and confined into an alginate shell for protection and separation from the surrounding myoglobin assay to allow for CO release studies by UV/Vis absorption without interference from highly-absorptive oximeCORM@IONP.
View Article and Find Full Text PDFMaghemite (Fe2O3) iron oxide nanoparticles (IONPs) were synthesized, modified with covalent surface-bound CO-releasing molecules of a tri(carbonyl)-chlorido-phenylalaninato-ruthenium(II) complex (CORM), and coated with a dextran polymer. The time- and temperature-dependent CO release from this CORM-3 analogue was followed by a myoglobin assay. A new measurement method for the myoglobin assay was developed, based on confining "water-soluble" polymer-coated Dextran500k@CORM@IONP particles in hollow spheres of nontoxic and easily prepared calcium alginate.
View Article and Find Full Text PDFPlatinum(iv) complexes take advantage of the exclusive conditions that occur within the tumor to carry out their cytotoxic activity. On the other hand, silk fibroin has natural properties which make it very interesting as a biomaterial: high biocompatibility, biodegradability, low immunogenicity, high cellular penetration capacity and high reactive surface. Herein we report the preparation of silk fibroin nanoparticles (SFNs) loaded with the hydrophobic Pt(iv) complex cis,cis,trans-[Pt(NH(3))(2)Cl(2)(O(2)CC(6)H(5))(2)] (PtBz).
View Article and Find Full Text PDFEfforts to replace noble-metal catalysts by low-cost alternatives are of constant interest. The organometallic, non-aqueous wet-chemical synthesis of various hitherto unknown nanocrystalline Ni/Ga intermetallic materials and the use of NiGa for the selective semihydrogenation of alkynes to alkenes are reported. Thermal co-hydrogenolysis of the all-hydrocarbon precursors [Ni(COD)2] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in high-boiling organic solvents mesitylene and n-decane in molar ratios of 1 : 1, 2 : 3 and 3 : 1 yields the nano-crystalline powder materials of the over-all compositions NiGa, Ni2Ga3 and Ni3Ga, respectively.
View Article and Find Full Text PDFMicrowave-induced decomposition of the transition metal amidinates {[Me(C(N(i)Pr)2)]Cu}2 (1) and [Me(C(N(i)Pr)2)]2Zn (2) in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) or in propylene carbonate (PC) gives copper and zinc nanoparticles which are stable in the absence of capping ligands (surfactants) for more than six weeks. Co-decomposition of 1 and 2 yields the intermetallic nano-brass phases β-CuZn and γ-Cu3Zn depending on the chosen molar ratios of the precursors. Nanoparticles were characterized by high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), dynamic light scattering and powder X-ray diffractometry.
View Article and Find Full Text PDFMagnetic iron oxide, maghemite (Fe2O3) nanoparticles with covalent surface-bound CO-releasing molecules (CORMs) can be triggered to release CO through heating in an alternating magnetic field. In the proof-of-concept study the rate of CO-release from [RuCl(CO3)(μ-DOPA)]@maghemite nanoparticles was doubled upon exposure to an external alternating magnetic field (31.7 kAm(-1), 247 kHz, 25 °C, 39.
View Article and Find Full Text PDF