Effect of different silica coatings on the toxicity of upconversion nanoparticles on RAW 264.7 macrophage cells

• Cynthia Kembuan,
• Helena Oliveira and
• Christina Graf

Beilstein J. Nanotechnol. 2021, 12, 35–48, doi:10.3762/bjnano.12.3

• -shelled samples (sample UC@thick_RBITC_NH2). The silica shells of the dye-doped samples were slightly thicker than those of the samples without the dye, as APS and RBITC-APS slightly increase the porosity of the silica shell. Consequently, identical amounts of silica per particle result in slightly

Bio-imaging with the helium-ion microscope: A review

• Matthias Schmidt,
• James M. Byrne and
• Ilari J. Maasilta

Beilstein J. Nanotechnol. 2021, 12, 1–23, doi:10.3762/bjnano.12.1

Oxidation of Au/Ag films by oxygen plasma: phase separation and generation of nanoporosity

• Abdel-Aziz El Mel,
• Said A. Mansour,
• Mujaheed Pasha,
• Atef Zekri,
• Janarthanan Ponraj,
• Akshath Shetty and
• Yousef Haik

Beilstein J. Nanotechnol. 2020, 11, 1608–1614, doi:10.3762/bjnano.11.143

• originates from their special architecture and porosity, resulting in an extremely high specific surface area, at the nanometer scale, which can be suitable for many applications [10]. Details related to the silver oxidation process using either oxygen plasma or ozone have been previously reported [6][7][8

• . Interestingly, these microspheres do not cover the entire film surface but are rather randomly distributed over the surface. Moreover, when examining the surface an increase in porosity is noticed, probably as a consequence of the decrease in film density due to the migration of the oxidized silver toward the

• , resulting in a mobility decrease at the surface; and (2) the high porosity of the film which serves as a support for the surface diffusion of silver. The clusters formed during the early stages of the process serve as nucleation sites which grow into larger spheres as the oxidation process evolves. The

Fabrication of nano/microstructures for SERS substrates using an electrochemical method

• Jingran Zhang,
• Tianqi Jia,
• Xiaoping Li,
• Junjie Yang,
• Zhengkai Li,
• Guangfeng Shi,
• Xinming Zhang and
• Zuobin Wang

Beilstein J. Nanotechnol. 2020, 11, 1568–1576, doi:10.3762/bjnano.11.139

• mechanical stirring cooling system. To study the influence of surface conditions (e.g., porosity and roughness) on the SERS intensity, the duration of the PEO treatment was set as the single variable (1, 2, and 5 min), as shown in Table 1. The structured Mg surfaces were coated with Au of varying thickness

One-step synthesis of carbon-supported electrocatalysts

• Sebastian Tigges,
• Nicolas Wöhrl,
• Ivan Radev,
• Ulrich Hagemann,
• Markus Heidelmann,
• Thai Binh Nguyen,
• Stanislav Gorelkov,
• Stephan Schulz and
• Axel Lorke

Beilstein J. Nanotechnol. 2020, 11, 1419–1431, doi:10.3762/bjnano.11.126

• ) micrograph in Figure 2a. Pt-NPs (black dots) are homogeneously distributed across the entire porous carbon sheet (grey areas). The porosity of the support can be observed in the dark-field TEM micrograph (Figure 2b) and has been reported to be beneficial in electrocatalysis, as it reduces mass transport

Structure and electrochemical performance of electrospun-ordered porous carbon/graphene composite nanofibers

• Yi Wang,
• Yanhua Song,
• Chengwei Ye and
• Lan Xu

Beilstein J. Nanotechnol. 2020, 11, 1280–1290, doi:10.3762/bjnano.11.112

• were submitted to carbonization under a N2 atmosphere at 1100 °C. The influence of the ordering and porosity of CGCNFs on their electrochemical performance was studied. The results showed that by adding deionized water to the spinning solution one could increase the number of mesopores and the specific

• specific surface area. The increase in the specific surface area of the electrode due to increased porosity facilitates ion transportation, which increases the conductivity of monolithic electrodes [24][25][26]. Although the porous carbon nanofibers have a high specific surface area, their low electrical

• mesopores to be used as a material to synthesize supercapacitor electrodes. The method used in our previous work to induce porosity was the carbonization of the OPPGCNFs, obtained by MPEM, at 1100 °C under a N2 atmosphere [33]. The results showed that the number of mesopores and the specific surface area of

Gas sorption porosimetry for the evaluation of hard carbons as anodes for Li- and Na-ion batteries

• Yuko Matsukawa,
• Fabian Linsenmann,
• Maximilian A. Plass,
• George Hasegawa,
• Katsuro Hayashi and
• Tim-Patrick Fellinger

Beilstein J. Nanotechnol. 2020, 11, 1217–1229, doi:10.3762/bjnano.11.106

• importantly CO2, sorption porosimetry turned out to be the preferred methods to evaluate the likelihood for excessive irreversible capacities. The methods are also useful to select the relatively most promising active materials within chemically similar materials. A quantitative relation of porosity

• size assignments [27]. Considering the expected complex interdependencies of the porosity/pore size distribution of HCs with their electrochemical properties, a combination of these sorption techniques seems reasonable. To minimize capacity losses due to SEI formation in graphite-based LIBs, the

• appears to be more reasonable. Pore size distributions of the HT carbons derived from CO2 sorption data using the Monte Carlo method were centered around 0.5 nm with less abundant larger pores between 0.7 and 1.5 nm (Figure 2b). RF-1600 does not have pores smaller than 0.5 nm with main porosity

Plant growth regulation by seed coating with films of alginate and auxin-intercalated layered double hydroxides

• Vander A. de Castro,
• Valber G. O. Duarte,
• Danúbia A. C. Nobre,
• Geraldo H. Silva,
• Vera R. L. Constantino,
• Frederico G. Pinto,
• Willian R. Macedo and
• Jairo Tronto

Beilstein J. Nanotechnol. 2020, 11, 1082–1091, doi:10.3762/bjnano.11.93

• in the UV–vis region (37.1%) and the Zn/Al molar ratio of 2, the following formula is proposed for the hybrid material: Zn2Al(OH)6](NAA)·3H2O (calculated: 37.1% of NAA; 10.8% of H2O). The morphology and porosity of LDHs can change depending on the synthesis method and also on the chemical

Highly sensitive detection of estradiol by a SERS sensor based on TiO₂ covered with gold nanoparticles

• Andrea Brognara,
• Ili F. Mohamad Ali Nasri,
• Beatrice R. Bricchi,
• Andrea Li Bassi,
• Caroline Gauchotte-Lindsay,
• Matteo Ghidelli and
• Nathalie Lidgi-Guigui

Beilstein J. Nanotechnol. 2020, 11, 1026–1035, doi:10.3762/bjnano.11.87

• Si(100) and soda-lime glass substrates, which were mounted on a sample holder at a fixed target-to-substrate distance of 5 cm. Changing the background pressure within the deposition chamber allowed for a tuning of the film morphology (i.e., a higher pressure resulted in a higher film porosity) [28

• porosity were deposited by pulsed laser deposition (PLD) as already reported in [28]. By increasing the background O2 pressure during deposition it is possible to deposit films that are more porous. Samples were therefore synthetized at background pressures of 8 or 12 Pa. Au layers were then evaporated on

• phase (as demonstrated by Raman spectra, not shown) and caused dewetting in the Au layer with the subsequent formation of NPs [32]. Evaporation and dewetting of Au on TiO2 layers with different porosity was carried out to exploit the effect of the surface morphology on the formation of Au NPs, yielding

Gas-sensing features of nanostructured tellurium thin films

• Dumitru Tsiulyanu

Beilstein J. Nanotechnol. 2020, 11, 1010–1018, doi:10.3762/bjnano.11.85

• were interpreted in terms of an increase in disorder (amorphization), leading to an increase in the surface chemical activity of chalcogenides, as well as an increase in the active surface area due to substrate porosity. Keywords: gas-sensing properties; NO2; tellurium thin films; nanocrystalline

• increase in the chemical activity of chalcogenides at the surface when disorder (amorphization) increases [32][33] and to the increase in the active area caused by substrate porosity. Another interesting feature observed in the experiments was the spontaneous reduction (or sometimes increase) in the gas

• surface area due to increased substrate porosity. SEM of Te films grown: a) on Pyrex glass at a rate of 10 nm/s and b) on nanostructured Al2O3 substrates at a rate of 30 nm/s. Scale bar is 5 µm. XRD diffraction patterns of Te films grown on Pyrex glass (A) or nanostructured Al2O3 (B) substrates

Electrochemical nanostructuring of (111) oriented GaAs crystals: from porous structures to nanowires

• Elena I. Monaico,
• Eduard V. Monaico,
• Veaceslav V. Ursaki,
• Shashank Honnali,
• Vitalie Postolache,
• Karin Leistner,
• Kornelius Nielsch and
• Ion M. Tiginyanu

Beilstein J. Nanotechnol. 2020, 11, 966–975, doi:10.3762/bjnano.11.81

• electrolytes is performed in galvanostatic and potentiostatic anodization modes. Anodization in NaCl electrolytes was found to result in the formation of porous structures with porosity controlled either by current under the galvanostatic anodization, or by the potential under the potentiostatic anodization

• intersect each other without changing their direction of propagation during growth. As one can see from Figure 1A, the degree of porosity decreases with decreasing the anodization current density. The situation is different when the GaAs crystals are anodized on the (111)B surface. During anodization in the

• galvanostatic mode at current densities similar to those applied during anodizing the (111)A surface (15, 10, and 5 mA), three porous layers are formed with different degrees of porosity, but the pores are parallel to each other and they grow perpendicularly to the crystal surface (Figure 1B). The same

Atomic layer deposition for efficient oxygen evolution reaction at Pt/Ir catalyst layers

• Stefanie Schlicht,
• Korcan Percin,
• Stefanie Kriescher,
• André Hofer,
• Claudia Weidlich,
• Matthias Wessling and
• Julien Bachmann

Beilstein J. Nanotechnol. 2020, 11, 952–959, doi:10.3762/bjnano.11.79

• prominent presence of catalytically more active Ir at the surface. The geometric effect of felt porosity is also prevalent on the graphs. The best sample achieves 26.8 μA·cm−2 at η = 0.4 V, which corresponds to a mass activity of 557 A·g−1. This catalyst coating yields (as compared to the thermal

A 3D-polyphenylalanine network inside porous alumina: Synthesis and characterization of an inorganic–organic composite membrane

• Jonathan Stott and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2020, 11, 938–951, doi:10.3762/bjnano.11.78

• -dimensional fibrillar network with intrinsic porosity was formed in DCM, whereas in THF, a dense and smooth polypeptide film was observed. A post-treatment with a mixture of chloroform and dichloroacetic acid leads to rearrangement of the morphology of the grafted polymer films. The analysis by scanning

• functionalization [33][34]. The surface of ALOX-membranes contains hydroxyl groups, which can be used for chemical modification [35]. Their porosity predetermines different conditions in wet chemical surface functionalization due to a restricted and diffusion limited transport of reactants to the inner surface of

Band tail state related photoluminescence and photoresponse of ZnMgO solid solution nanostructured films

• Vadim Morari,
• Aida Pantazi,
• Nicolai Curmei,
• Vitalie Postolache,
• Emil V. Rusu,
• Marius Enachescu,
• Ion M. Tiginyanu and
• Veaceslav V. Ursaki

Beilstein J. Nanotechnol. 2020, 11, 899–910, doi:10.3762/bjnano.11.75

• amplitude of potential fluctuations is determined by the degree of doping and conductivity compensation. In porous semiconductors the amplitude is determined by the degree of porosity, while it is a function of local fluctuations of the composition in solid solutions, including ZnMgO. The observation of the

A set of empirical equations describing the observed colours of metal–anodic aluminium oxide–Al nanostructures

• Cristina V. Manzano,
• Jakob J. Schwiedrzik,
• Gerhard Bürki,
• Laszlo Pethö,
• Johann Michler and
• Laetitia Philippe

Beilstein J. Nanotechnol. 2020, 11, 798–806, doi:10.3762/bjnano.11.64

• thickness and porosity of the nanostructures was determined, which describes a gamut of colours. The proposed mathematical model can be applied in different fields, such as wavelength absorbers, RGB (red, green, blue) display devices, as well as chemical or optical sensors. Keywords: anodic aluminium oxide

• . In a previous study by our group, the effects of morphological parameters (pore diameters, interpore distance, porosity, and nanostructure order) on the colours and the effective refractive index of AAO films were studied on metal–AAO–Al nanostructures [4]. Thickness and porosity are the two main

• design of colours by choosing a specific thickness [14]. Also, there is a model based on optical measurements (ellipsometry integrating indirectly thickness, porosity) in combination with total reflectance measurements to access the colours, in terms of L*a*b* values, of AAO–Al nanostructures filled with

Nickel nanoparticles supported on a covalent triazine framework as electrocatalyst for oxygen evolution reaction and oxygen reduction reactions

• Secil Öztürk,
• Yu-Xuan Xiao,
• Dennis Dietrich,
• Beatriz Giesen,
• Juri Barthel,
• Jie Ying,
• Xiao-Yu Yang and
• Christoph Janiak

Beilstein J. Nanotechnol. 2020, 11, 770–781, doi:10.3762/bjnano.11.62

• nitrogen-containing aromatic polymer frameworks with triazine rings, which exhibit high surface area, porosity, and thermal and chemical stability [21][22]. CTFs are promising materials for applications such as catalysts or catalyst support [23][24][25] and for energy storage and conversion [26][27][28

• ]. CTFs can be synthesized through different methods and under different reaction conditions, which enables the control over porosity and surface area [29][30][31][32]. The nitrogen moieties within the CTFs can provide coordination anchors or support for metal species [33][34]. They allow for the

• according to the literature by the ionothermal method [32][42]. Since the synthesis parameters, such as reaction temperature, affect texture, porosity and nitrogen content of the framework, two different reaction temperatures (400 and 600 °C) have been used for the synthesis (Scheme S1, Supporting

Adsorptive removal of bulky dye molecules from water with mesoporous polyaniline-derived carbon

• Hyung Jun An,
• Jong Min Park,
• Nazmul Abedin Khan and
• Sung Hwa Jhung

Beilstein J. Nanotechnol. 2020, 11, 597–605, doi:10.3762/bjnano.11.47

• synthesis, high conductivity and nitrogen content. Porous carbon materials, with high porosity and nitrogen content, have also been obtained from PANI. In other words, functional carbon, for catalysts and supercapacitors can be derived from high temperature carbonization of PANI, especially in the co

• JGB under a wide range of pH values (from 2 to 12). Results and Discussion Characterization of polyaniline-derived carbon (PDC) The porosity and pore size distribution of the adsorbents were characterized with nitrogen adsorption at 77 K. As shown in Figure 1a, the porosity of the PDC materials was

• considerable when the pyrolysis temperature was equal to or higher than 700 °C. The detailed porosity data are summarized in Supporting Information File 1, Table S1. With increasing pyrolysis temperature up to 800 °C, the BET surface area, total pore volume and mesopore volume increased. However, all of the

Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

• Matthias Simolka,
• Hanno Kaess and
• Kaspar Andreas Friedrich

Beilstein J. Nanotechnol. 2020, 11, 583–596, doi:10.3762/bjnano.11.46

• the coexistence of a lithiated and delithiated phase for LFP [78]. Additionally, other mechanisms and factors, e.g., the generation of surface layers, porosity and tortuosity of electrodes, electrolyte salts and concentration gradients in the electrodes are affecting the ion transport and therefore

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

• LbL multistep technique and can be easily controlled by varying the polymerization time. This single-step technique resulted in a wall thickness similar to the LbL multistep technique and was applicable to other particles of different size and porosity. Because of the broad absorption and interesting

Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions

• Robert Kozioł,
• Marcin Łapiński,
• Paweł Syty,
• Damian Koszelow,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2020, 11, 494–507, doi:10.3762/bjnano.11.40

• , and thus the amplification of the electromagnetic field, was observed in several directions, depending on the direction of illumination. The plasmon resonance also has an effect on the porosity of the metallic nanostructures [26][27], which is why determining the shape and surface quality is extremely

An advanced structural characterization of templated meso-macroporous carbon monoliths by small- and wide-angle scattering techniques

• Felix M. Badaczewski,
• Marc O. Loeh,
• Torben Pfaff,
• Dirk Wallacher,
• Daniel Clemens and
• Bernd M. Smarsly

Beilstein J. Nanotechnol. 2020, 11, 310–322, doi:10.3762/bjnano.11.23

• ][7][8]. The turbostratic microstructure of these “non-graphitic” carbon materials combined with variable conductivity and a significant nanoscale disordered porosity are typical features of this kind of carbon materials. Templating strategies are meanwhile well established to endow carbon materials

• with defined porosity on the nanometer scale, in particular to enhance the surface area and to control the pore size [9][10][11][12]. This study is dedicated to a quantitative determination of the porosity, e.g., pore size, pore volume and pore shape of carbon materials prepared by hard-templating of

• can markedly affect the nanoscale porosity [13][14][15][16][17][18][19][20][21]. Hence, a combined in-depth elucidation of meso/microporosity and the graphene-based structure upon heat treatment is pursued in this study to obtain a profound understanding of the relationship between the changes in the

Facile biogenic fabrication of hydroxyapatite nanorods using cuttlefish bone and their bactericidal and biocompatibility study

• Satheeshkumar Balu,
• Manisha Vidyavathy Sundaradoss,
• Swetha Andra and
• Jaison Jeevanandam

Beilstein J. Nanotechnol. 2020, 11, 285–295, doi:10.3762/bjnano.11.21

• powder to prepare Hap is their cost effectiveness and ecologically friendly nature, high availability, enhanced interconnectivity, and biocompatibility [14]. Recently, it was reported that the bonding ability of the scaffold with surrounding tissues is determined by the porosity of the material and that

• porosity and high surface-to-volume ratio when compared to spherical nanometer-sized Hap particles, which facilitates interconnectivity and improves targeted cell internalization efficiency [22]. Thus, the aim of the present work is to use a simple, facile, unique, safe and cost-effective precipitation

• ]. However, the Hap NRs in the present work are nonporous as observed in the TEM images, which may affect the biocompatibility, while utilizing them as scaffolds. Hence, the calcination temperature must be optimized in the future studies to provide porosity in the Hap NRs to improving their biocompatibility

High-performance asymmetric supercapacitor made of NiMoO₄ nanorods@Co₃O₄ on a cellulose-based carbon aerogel

• Meixia Wang,
• Jing Zhang,
• Xibin Yi,
• Benxue Liu,
• Xinfu Zhao and
• Xiaochan Liu

Beilstein J. Nanotechnol. 2020, 11, 240–251, doi:10.3762/bjnano.11.18

• a capacitance retention of 84.1% after 2000 cycles [23]. Metal-organic frameworks (MOFs) with high porosity and tunable functionality are ideal sacrificial templates to synthesize metal oxides [24][25][26]. As a MOF derivative, Co3O4 derived from the zeolitic imidazolate framework-67 (ZIF-67) is

• considered an ideal supporting material to hybridize with electroactive materials because of its low cost, easy fabrication, large surface area, interconnected porosity and high electrical conductivity [30][31]. Due to its micro/mesoporous 3D morphology with large open pores, it offers more space to grow

• sample is characterized by a combination of type–IV and type–I isotherms, indicating the presence of micro- and mesopores with monolayer–multilayer adsorption. Furthermore, two distinct pore distribution curves are observed in the inset of Figure 5c revealing a hierarchical porosity: micro/mesopores

Synthesis of amorphous and graphitized porous nitrogen-doped carbon spheres as oxygen reduction reaction catalysts

• Maximilian Wassner,
• Markus Eckardt,
• Andreas Reyer,
• Thomas Diemant,
• Michael S. Elsaesser,
• R. Jürgen Behm and
• Nicola Hüsing

Beilstein J. Nanotechnol. 2020, 11, 1–15, doi:10.3762/bjnano.11.1

• doping on the carbon sphere morphology, structure, elemental composition, N bonding configuration as well as porosity is investigated in detail. For the N-doped carbon spheres, the maximum nitrogen content was found at a doping temperature of 700 °C, with a decrease of the N content for higher

• microporosity of the materials is critical for an efficient ORR. Keywords: amorphous carbon; graphitized carbon; hydrothermal carbonization; nitridation; nitrogen doping; oxygen reduction reaction (ORR); porosity; Introduction Fuel cells and metal–air batteries are important renewable energy technologies

• polypyrrole instead of ammonia resulted in pyridinic or pyrrolic N moieties, respectively [18]. Beside the N bonding configuration, the ORR activity is affected by the N content, the surface area (porosity) and possibly the degree of graphitization [27]. The nitrogen content defines, among others, the density

Advanced hybrid nanomaterials

• Andreas Taubert,
• Fabrice Leroux,
• Pierre Rabu and
• Verónica de Zea Bermudez

Beilstein J. Nanotechnol. 2019, 10, 2563–2567, doi:10.3762/bjnano.10.247

• yield diverse materials, which were found to depend on the P/Ti atom ratio [20]. The ratio was found to determine the particle size and the aggregation state and thereby could strongly tune the porosity of the resulting materials. Colloidal chemistry with patchy silica nanoparticles was employed to