TY - JOUR A1 - Modena, Mario M. A1 - Rühle, Bastian A1 - Burg, Thomas P. A1 - Wuttke, Steffan T1 - Nanoparticle characterization: What to measure? JF - Advanced Materials N2 - What to measure? is a key question in nanoscience, and it is not straightforward to address as different physicochemical properties define a nanoparticle sample. Most prominent among these properties are size, shape, surface charge, and porosity. Today researchers have an unprecedented variety of measurement techniques at their disposal to assign precise numerical values to those parameters. However, methods based on different physical principles probe different aspects, not only of the particles themselves, but also of their preparation history and their environment at the time of measurement. Understanding these connections can be of great value for interpreting characterization results and ultimately controlling the nanoparticle structure–function relationship. Here, the current techniques that enable the precise measurement of these fundamental nanoparticle properties are presented and their practical advantages and disadvantages are discussed. Some recommendations of how the physicochemical parameters of nanoparticles should be investigated and how to fully characterize these properties in different environments according to the intended nanoparticle use are proposed. The intention is to improve comparability of nanoparticle properties and performance to ensure the successful transfer of scientific knowledge to industrial real‐world applications. KW - Nanoparticle characterization KW - Nanoparticles KW - Porosity KW - Shape KW - Size PY - 2019 DO - https://doi.org/10.1002/adma.201901556 SN - 0935-9648 SN - 1521-4095 VL - 31 IS - 32 SP - 1901556, 1 EP - 26 PB - Wiley AN - OPUS4-49129 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brüngel, R. A1 - Rückert, J. A1 - Wohlleben, W. A1 - Babick, F. A1 - Ghanem, A. A1 - Gaillard, C. A1 - Mech, A. A1 - Rauscher, H. A1 - Hodoroaba, Vasile-Dan A1 - Weigel, S. A1 - Friedrich, C. M. T1 - NanoDefiner e-Tool: An Implemented Decision Support Framework for Nanomaterial Identification JF - Materials N2 - The European Commission’s recommendation on the definition of nanomaterial (2011/696/EU) established an applicable standard for material categorization. However, manufacturers face regulatory challenges during registration of their products. Reliable categorization is difficult and requires considerable expertise in existing measurement techniques (MTs). Additionally, organizational complexity is increased as different authorities’ registration processes require distinct reporting. The NanoDefine project tackled these obstacles by providing the NanoDefiner e-tool: A decision support expert system for nanomaterial identification in a regulatory context. It providesMT recommendations for categorization of specific materials using a tiered approach (screening/confirmatory), and was constructed with experts from academia and industry to be extensible, interoperable, and adaptable for forthcoming revisions of the nanomaterial definition. An implemented MT-driven material categorization scheme allows detailed description. Its guided workflow is suitable for a variety of user groups. Direct feedback and explanation enable transparent decisions. Expert knowledge is Held in a knowledge base for representation of MT performance criteria and physicochemical particle type properties. Continuous revision ensured data quality and validity. Recommendations were validated by independent case studies on industry-relevant particulate materials. Besides supporting material identification and registration, the free and open-source e-tool may serve as template for other expert systems within the nanoscience domain. KW - EC nanomaterial definition KW - Decision support KW - Expert system KW - Nanomaterial KW - Nanoparticles PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492449 DO - https://doi.org/10.3390/ma12193247 VL - 12 IS - 19 SP - 3247 PB - MDPI CY - Basel, CH AN - OPUS4-49244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fletcher, D. C. A1 - Hunter, R. A1 - Xia, W. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Blackburn, E. A1 - Kulak, A. A1 - Xin, H. A1 - Schnepp, Z. T1 - Scalable synthesis of dispersible iron carbide (Fe3C) nanoparticles by ‘nanocasting’ JF - Journal of Materials Chemistry A N2 - Metal carbides have shown great promise in a wide range of applications due to their unique catalytic, electrocatalytic and magnetic properties. However, the scalable production of dispersible metal carbide nanoparticles remains a challenge. Here, we report a simple and scalable route to dispersible iron carbide (Fe3C) nanoparticles. This uses MgO nanoparticles as a removable ‘cast’ to synthesize Fe3C nanoparticles from Prussian blue (KFeIII[FeII(CN)6]). Electron tomography demonstrates how nanoparticles of the MgO cast encase the Fe3C nanoparticles to prevent sintering and agglomeration during the high-temperature synthesis. The MgO cast is readily removed with ethylenediaminetetraacetic acid (EDTA) to generate Fe3C nanoparticles that can be used to produce a colloidal ferrofluid or dispersed on a support material. KW - Small-angle scattering KW - SAXS KW - Metal carbides KW - Nanoparticles KW - Nanocasting PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486295 DO - https://doi.org/10.1039/C9TA06876G SN - 2050-7488 SN - 2050-7496 VL - 7 IS - 33 SP - 19506 EP - 19512 PB - Royal Society of Chemistry (RSC) AN - OPUS4-48629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pellegrino, F. A1 - Sordello, F. A1 - Mino, L. A1 - Minero, C. A1 - Hodoroaba, Vasile-Dan A1 - Martra, G. A1 - Maurino, V. T1 - Formic acid photoreforming for hydrogen production on shape-controlled anatase TiO2 nanoparticles: Assessment of the role of fluorides, {101}/{001} surfaces ratio, and platinization JF - ACS Catalysis N2 - Hydrogen production via formate photoreforming on TiO2 is characterized by marked dependence on the ratio between {101} and {001} surfaces for anatase nanoparticles. We observed higher rates of hydrogen Evolution with the increase of the {101} facets presence, owing to their reductive nature. This helps the Pt photodeposition in the early stages of Irradiation and, then, the hydrogen ion reduction reaction. The selective photodeposition of 2 nm Pt nanoparticles on {101} facets was confirmed by transmission electron microscopy (TEM) micrographs. The results are confirmed also by experiments carried out without the use of Pt as cocatalyst and by photoelectrochemical measurements. The work also explains the marginal effect of the fluorination on the H2 evolution. KW - Titanium dioxide KW - Fluoride KW - Platinum KW - Nanoparticles KW - Controlled-shape KW - Hydrogen photoproduction KW - Surface PY - 2019 UR - https://pubs.acs.org/doi/10.1021/acscatal.9b01861 DO - https://doi.org/10.1021/acscatal.9b01861 SN - 2155-5435 VL - 9 IS - 8 SP - 6692 EP - 6697 PB - ACS Publications AN - OPUS4-48355 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yadav, Anur A1 - Iost, R. M. A1 - Neubert, T. J. A1 - Baylan, S. A1 - Schmid, Thomas A1 - Balasubramanian, Kannan T1 - Selective electrochemical functionalization of the graphene edge JF - Chemical Science N2 - We present a versatile and simple method using electrochemistry for the exclusive functionalization of the edge of a graphene monolayer with metal nanoparticles or polymeric amino groups. The attachment of metal nanoparticles allows us to exploit surface-enhanced Raman scattering to characterize the chemistry of both the pristine and the functionalized graphene edge. For the pristine patterned graphene edge, we observe the typical edge-related modes, while for the functionalized graphene edge we identify the chemical structure of the functional layer by vibrational fingerprinting. The ability to obtain single selectively functionalized graphene edges routinely on an insulating substrate opens an avenue for exploring the effect of edge chemistry on graphene properties systematically. KW - Graphene KW - Nanoparticles KW - Nanosciences KW - Surface-enhanced Raman scattering KW - Atomic force microscopy PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474357 DO - https://doi.org/10.1039/C8SC04083D SN - 2041-6520 VL - 10 IS - 3 SP - 936 EP - 942 PB - Royal Society of Chemistry AN - OPUS4-47435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sarhan, R. M. A1 - Koopman, W. A1 - Schuetz, R. A1 - Schmid, Thomas A1 - Liebig, F. A1 - Koetz, J. A1 - Bargheer, M. T1 - The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol JF - Scientific Reports N2 - Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding. KW - Nanoparticles KW - Plasmonic heating KW - Raman spectroscopy PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475140 DO - https://doi.org/10.1038/s41598-019-38627-2 SN - 2045-2322 VL - 9 IS - 1 SP - 3060, 1 EP - 8 PB - Nature Publishing Group AN - OPUS4-47514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gea, M. A1 - Bonetta, S. A1 - Iannarelli, L. A1 - Giovannozzi, A. M. A1 - Maurino, V. A1 - Bonetta, S. A1 - Hodoroaba, Vasile-Dan A1 - Armato, C. A1 - Rossi, A. M. A1 - Schilirò, T. T1 - Shape-engineered titanium dioxide nanoparticles (TiO2-NPs): cytotoxicity and genotoxicity in bronchial epithelial cells JF - Food and Chemical Toxicology N2 - The aim of this study was to evaluate cytotoxicity (WST-1 assay), LDH release (LDH assay) and genotoxicity (Comet assay) of three engineered TiO2-NPs with different shapes (bipyramids, rods, platelets) in comparison with two commercial TiO2-NPs (P25, food grade). After NPs characterization (SEM/T-SEM and DLS), biological effects of NPs were assessed on BEAS-2B cells in presence/absence of light. The cellular uptake of NPs was analyzed using Raman spectroscopy. The cytotoxic effects were mostly slight. After light exposure, the largest cytotoxicity (WST-1 assay) was observed for rods; P25, bipyramids and platelets showed a similar effect; no effect was induced by food grade. No LDH release was detected, confirming the low effect on plasma membrane. Food grade and platelets induced direct genotoxicity while P25, food grade and platelets caused oxidative DNA damage. No genotoxic or oxidative damage was induced by bipyramids and rods. Biological effects were overall lower in darkness than after light exposure. Considering that only food grade, P25 and platelets (more agglomerated) were internalized by cells, the uptake resulted correlated with genotoxicity. In conclusion, cytotoxicity of NPs was low and affected by shape and light exposure, while genotoxicity was influenced by cellular-uptake and aggregation tendency. KW - Nanoparticles KW - Shape-engineered KW - Raman spectroscopy KW - Genotoxic and oxidative damage KW - Cytotoxicity PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0278691519301036?via%3Dihub DO - https://doi.org/10.1016/j.fct.2019.02.043 SN - 0278-6915 SN - 1873-6351 VL - 127 SP - 89 EP - 100 PB - Elsevier AN - OPUS4-47532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saloga, Patrick E. J. A1 - Thünemann, Andreas T1 - Microwave-Assisted Synthesis of Ultrasmall Zinc Oxide Nanoparticles JF - Langmuir N2 - We report on ultrasmall zinc oxide single-crystalline nanoparticles of narrow size distribution and long-term colloidal stability. These oleate-stabilized nanoparticles were synthesized using microwave-assisted synthesis for 5 min, corresponding to a 99% decrease in synthesis time, when compared to the conventional synthesis method. It was observed that the average particle radius increases from 2.6 ± 0.1 to 3.8 ± 0.1 nm upon increasing synthesis temperature from 125 to 200 °C. This change also corresponded to observed changes in the optical band gap and the fluorescence energy of the particles, from 3.44 ± 0.01 to 3.36 ± 0.01 eV and from 2.20 ± 0.01 to 2.04 ± 0.01 eV, respectively. Small-angle X-ray scattering, dynamic light scattering, and UV–vis and fluorescence spectroscopy were employed for particle characterization. Debye–Scherrer analysis of the X-ray diffraction (XRD) pattern reveals a linear increase of the crystallite size with synthesis temperature. The consideration of the convolution of a Lorentz function with a Gaussian function for data correction of the instrumental peak broadening has a considerable influence on the values for the crystallite size. Williamson–Hall XRD analyses in the form of the uniform deformation model, uniform stress deformation model, and uniform deformation energy density model revealed a substantial increase of strain, stress, and deformation energy density of the crystallites with decreasing size. Exponential and power law models were utilized for quantification of strain, stress, and deformation energy density. KW - SAXS KW - Zinc oxide KW - Microwave synthesis KW - Nanoparticles PY - 2019 DO - https://doi.org/10.1021/acs.langmuir.9b01921 SN - 0743-7463 VL - 35 IS - 38 SP - 12469 EP - 12482 PB - American Chemical Society CY - Washington, D.C., USA AN - OPUS4-49136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -