Electrical characterization of single molecule and Langmuir–Blodgett monomolecular films of a pyridine-terminated oligo(phenylene-ethynylene) derivative

• Henrry M. Osorio,
• Santiago Martín,
• María Carmen López,
• Santiago Marqués-González,
• Simon J. Higgins,
• Richard J. Nichols,
• Paul J. Low and
• Pilar Cea

Beilstein J. Nanotechnol. 2015, 6, 1145–1157, doi:10.3762/bjnano.6.116

• area per molecule isotherms and Brewster angle microscopy images indicate that 1 forms true monolayers at the air–water interface. LB films of 1 were fabricated by deposition of the Langmuir films onto solid supports resulting in monolayers with surface coverage of 0.98 × 10−9 mol·cm−2. The morphology

• exhibiting a relatively high conductance. Results and Discussion Fabrication and characterization of Langmuir and Langmuir–Blodgett films Surface pressure–area per molecule (π–A) isotherms of 1 on a pure water subphase were recorded and reproducible results were obtained. One of these reproducible isotherms

• ·molecule−1·min−1. Under these experimental conditions, the isotherms were highly reproducible. A commercial mini-Brewster angle microscope (mini-BAM) from Nanofilm Technologie GmbH, Göttingen, Germany, was employed for the direct visualization of the monolayers at the air–water interface and a commercial

Palladium nanoparticles anchored to anatase TiO₂ for enhanced surface plasmon resonance-stimulated, visible-light-driven photocatalytic activity

• Kah Hon Leong,
• Hong Ye Chu,
• Shaliza Ibrahim and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2015, 6, 428–437, doi:10.3762/bjnano.6.43

• prepared samples are purely in crystalline anatase phase with the absence of band at 445 and 612 cm−1 corresponding to the rutile phase [52]. BET surface area and XPS analysis The nitrogen adsorption–desorption isotherms and corresponding pore size distribution of the prepared samples are depicted in

• Figure 5 and Figure S2 (Supporting Information File 1). As can be seen, all the samples possess a stepwise adsorption and desorption hysteresis, represented by type-IV isotherms, with the characteristics of a mesoporous material [53]. The variations in BET surface area, average pore size and pore volume

• ) was used to acquire the Raman and photoluminescence (PL) spectra with the excitation wavelengths of 514 and 325 nm, respectively. Brunauer–Emmett–Teller (BET) surface area, pore volume, and Barret–Joyner–Halenda (BJH) pore size distribution based on nitrogen adsorption–desorption isotherms were

Synthesis of boron nitride nanotubes and their applications

• Saban Kalay,
• Zehra Yilmaz,
• Ozlem Sen,
• Melis Emanet,
• Emine Kazanc and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 84–102, doi:10.3762/bjnano.6.9

• synthesized using annealing and ball milling methods and the hydrogen storage on the BNNTs was investigated experimentally by pressure–composition isotherms (PCI) and temperature-programmed desorption (TPD) methods [34]. The results showed that the hydrogen uptake capacity of purified BNNTs was 2.2 wt %. The

Manganese oxide phases and morphologies: A study on calcination temperature and atmospheric dependence

• Matthias Augustin,
• Daniela Fenske,
• Ingo Bardenhagen,
• Anne Westphal,
• Martin Knipper,
• Thorsten Plaggenborg,
• Joanna Kolny-Olesiak and
• Jürgen Parisi

Beilstein J. Nanotechnol. 2015, 6, 47–59, doi:10.3762/bjnano.6.6

• diameter of the α-Mn2O3 particles. From the isotherms recorded during N2 adsorption–desorption measurements (see Figure 8a) specific BET surface areas of 302, 30 and 20 m2/g were calculated for the Mn3O4, Mn5O8 and α-Mn2O3 samples, respectively. The porosity of the α-Mn2O3 particles observed in the TEM

• images (see Figure 7c,d) is also supported by the N2 adsorption–desorption isotherms, which exhibit hysteresis. As hysteresis is also observed in the Mn3O4 and Mn5O8 nanoparticle isotherms (but not supported by observations made in the TEM images for these species, see Figure 7a,b), two different

• measurements. Prior to the measurement, the material was kept for 18 h at 180 °C under vacuum to remove any residual gas and moisture from the sample. The adsorption–desorption isotherms were measured employing a Quantachrome Nova 2000E device at 77 K. The Brunauer–Emmet–Teller (BET) method was used to

Characterization of 10,12-pentacosadiynoic acid Langmuir–Blodgett monolayers and their use in metal–insulator–metal tunnel devices

• Saumya Sharma,
• Mohamad Khawaja,
• Manoj K. Ram,
• D. Yogi Goswami and
• Elias Stefanakos

Beilstein J. Nanotechnol. 2014, 5, 2240–2247, doi:10.3762/bjnano.5.233

• (PDA) and their use in metal–insulator–metal (MIM) devices were studied. The Langmuir monolayer behavior of the PDA film was studied at the air/water interface using surface tension–area isotherms of polymeric and monomeric PDA. Langmuir–Blodgett (LB, vertical deposition) and Langmuir–Schaefer (LS

• (>99.8%, Sigma-Aldrich). Figure 1 shows the molecular structure and UV-polymerized structure of the PDA molecule. The pH value of the water subphase was found to be 6.8. Surface tension–area isotherms were obtained using the KSV NIMA Langmuir–Blodgett Trough system for samples with varying volume and

Effects of surface functionalization on the adsorption of human serum albumin onto nanoparticles – a fluorescence correlation spectroscopy study

• Pauline Maffre,
• Stefan Brandholt,
• Karin Nienhaus,
• Li Shang,
• Wolfgang J. Parak and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2036–2047, doi:10.3762/bjnano.5.212

• the one that is quoted. Reversibility of corona formation A quantitative analysis in terms of equilibrium binding isotherms strictly only applies if corona formation is reversible. However, depending on the NP surface, protein adsorption may lead to tight binding, often accompanied by a substantial

Effects of palladium on the optical and hydrogen sensing characteristics of Pd-doped ZnO nanoparticles

• Anh-Thu Thi Do,
• Hong Thai Giang,
• Thu Thi Do,
• Ngan Quang Pham and
• Giang Truong Ho

Beilstein J. Nanotechnol. 2014, 5, 1261–1267, doi:10.3762/bjnano.5.140

• particle size. This includes the Brunauer–Emmett–Teller (BET) surface area analysis and the Barrett–Joyner–Halenda (BJH) pore size and volume analysis. The obtained isotherms of the ZnO and Pd/ZnO samples prepared in ethanol (Figure 2) correspond to a type III isotherm in the Brunauer classification [17

Nanoporous composites prepared by a combination of SBA-15 with Mg–Al mixed oxides. Water vapor sorption properties

• Amaury Pérez-Verdejo,
• Alvaro Sampieri,
• Heriberto Pfeiffer,
• Mayra Ruiz-Reyes,
• Juana-Deisy Santamaría and
• Geolar Fetter

Beilstein J. Nanotechnol. 2014, 5, 1226–1234, doi:10.3762/bjnano.5.136

• sorption capacity. Results and Discussion Textural properties Table 1 summarizes the main textural results obtained by X-ray diffraction (Supporting Information File 1) and N2 adsorption–desorption isotherms (Figure 1A). All isotherms are Type IV according to IUPAC classification. Both post-synthesis

• microporous blocked by Mg–Al–O particles and the calcination process. As N2 adsorption–desorption isotherms of HT/SBA (C) and HT/SBA (NC) composites and SBA-15 present similar profile curves (Figure 1), they can also be structurally analogous and such profiles indicate no mesoporous blocking. The resulting

• N2 adsorption–desorption behavior (Figure 1A) and the BJH pore diameter distribution (Figure 1B). Indeed, the N2 adsorption–desorption isotherms of the HT/SBA(C) and HT/SBA(NC) as well as their pore distribution are similar to those observed in the SBA-15. In contrast, the N2 adsorption–desorption

Volcano plots in hydrogen electrocatalysis – uses and abuses

• Paola Quaino,
• Fernanda Juarez,
• Elizabeth Santos and
• Wolfgang Schmickler

Beilstein J. Nanotechnol. 2014, 5, 846–854, doi:10.3762/bjnano.5.96

• in detail in a a recent communication [25], where we have also calculated the isotherms for both species of adsorbed hydrogen on Pt(111). In any case, the interaction between the two species makes it quite difficult to calculate the adsorption free energy of the true intermediate state by DFT. In the

Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications

• Hua Bing Tao,
• Hong Bin Yang,
• Jiazang Chen,
• Jianwei Miao and
• Bin Liu

Beilstein J. Nanotechnol. 2014, 5, 770–777, doi:10.3762/bjnano.5.89

• heterojunction. (a) FESEM image of CN/CNS heterostructure, (b) XRD and (c) nitrogen adsorption–desorption isotherms and (d) pore size distribution (insert) of CN, CNS and CN/CNS heterostructure. TEM (a) and HRTEM (b) images of a CN/CNS heterostructure. (a) Photoluminescence of CN, CNS and CN/CNS in aqueous

Effects of the preparation method on the structure and the visible-light photocatalytic activity of Ag₂CrO₄

• Difa Xu,
• Shaowen Cao,
• Jinfeng Zhang,
• Bei Cheng and
• Jiaguo Yu

Beilstein J. Nanotechnol. 2014, 5, 658–666, doi:10.3762/bjnano.5.77

• hydrothermal methods. Brunauer–Emmett–Teller (BET) surface area and pore size distributions Figure 4 shows the nitrogen adsorption–desorption isotherms and the corresponding pore size distributions of the as-prepared Ag2CrO4 photocatalysts. According to the Brunauer–Deming–Deming–Teller classification, the

• isotherms of all Ag2CrO4 samples are of type IV, indicating the presence of mesopores (2–50 nm) [56][57][58]. Moreover, the shapes of the hysteresis loops are of type H3 at the high relative pressure range from 0.8 to 1.0, which suggests the formation of large mesopores and macropores [56]. The pore size

• , Japan). BaSO4 was used as a reflectance standard. The nitrogen adsorption and desorption isotherms were measured by using an ASAP 2020 system (Micromertitics instruments, USA) after the samples were degassed at 180 °C. The SBET was determined by a multipoint BET method using the adsorption data in the

Controlled synthesis and tunable properties of ultrathin silica nanotubes through spontaneous polycondensation on polyamine fibrils

• Jian-Jun Yuan,
• Pei-Xin Zhu,
• Daisuke Noda and
• Ren-Hua Jin

Beilstein J. Nanotechnol. 2013, 4, 793–804, doi:10.3762/bjnano.4.90

• pore size distributions of the silica nanotubes and nanoribbons shown in Figure 1 were characterized with nitrogen adsorption and desorption measurements. As shown in Figure 2A, the BET adsorption–desorption isotherms of both silica nanotubes and nanoribbons can be described as type-IV hysteresis loops

• performed by adding 1.5 mL of MS51 into 15 mL of aqueous dispersion of LPEI aggregates for 1.0 h at room temperature. N2 adsorption/desorption isotherms (A) and BJH pore-size distribution curve obtained from the adsorption branch (B) of silica nanoribbon and silica nanotube. The synthesis conditions are the

• mL of MS51 was added into 15 mL of aqueous dispersion of LPEI aggregates (pH 7.0) and stirred for 1 h at room temperature. N2 adsorption/desorption isotherms (A) and BJH pore-size distribution curves obtained from the adsorption branch (B) of silica nanostructures synthesized by using silica source

A facile synthesis of a carbon-encapsulated Fe₃O₄ nanocomposite and its performance as anode in lithium-ion batteries

• Raju Prakash,
• Katharina Fanselau,
• Shuhua Ren,
• Tapan Kumar Mandal,
• Christian Kübel,
• Horst Hahn and
• Maximilian Fichtner

Beilstein J. Nanotechnol. 2013, 4, 699–704, doi:10.3762/bjnano.4.79

• spacings fit very well to the cubic Fe3O4 (space group Fd3m) detected by XRD. The encapsulated Fe3O4 particles have diameters in the order of 30 nm. The lattice spacing of the adjacent graphitic layers is typically around 0.36 nm. The nitrogen adsorption–desorption measurement shows type-IV isotherms with

Influence of the solvent on the stability of bis(terpyridine) structures on graphite

• Daniela Künzel and
• Axel Groß

Beilstein J. Nanotechnol. 2013, 4, 269–277, doi:10.3762/bjnano.4.29

• rather well with experimental findings, where the analysis of Langmuir adsorption isotherms has resulted in a 3,3′-BTP adsorption enthalpy of −340 meV at the solid/liquid interface [2]. In contrast to the observations under vacuum conditions, it might be that force fields tend to underestimate the

Distribution of functional groups in periodic mesoporous organosilica materials studied by small-angle neutron scattering with in situ adsorption of nitrogen

• Monir Sharifi,
• Dirk Wallacher and
• Michael Wark

Beilstein J. Nanotechnol. 2012, 3, 428–437, doi:10.3762/bjnano.3.49

• ). Nitrogen adsorption on pristine benzene-PMO (squares) exhibits type IV isotherms [33] showing shapes characteristic for the presence of mesopores; their average diameters were determined by DFT-based analysis [34] to be about 3.8 nm (Figure 1 inset). At low relative pressures the amount of adsorbed gas

• now diameters in the range of 2–4 nm (triangles, inset in Figure 1) results. It is notable that the obvious difference in the isotherms of both functionalized PMO materials is not only explained by the higher loading but occurs especially due to the harsh acidic conditions needed for sulfonation of

• sulfuric acid for 12 h under reflux or with H2O2 (48 h). Supporting Information File 1 shows the nitrogen isotherms taken before and after the different treatments, demonstrating that especially the strong acidic conditions destroy parts of the regular mesoporous network. Figure 2 displays characteristic

Reduced electron recombination of dye-sensitized solar cells based on TiO₂ spheres consisting of ultrathin nanosheets with [001] facet exposed

• Hongxia Wang,
• Meinan Liu,
• Cheng Yan and
• John Bell

Beilstein J. Nanotechnol. 2012, 3, 378–387, doi:10.3762/bjnano.3.44

• nanosheets to realize a minimum surface energy. Some spheres have pits on the surface, which may be due to the insufficient reaction duration. The measurement of the N2 adsorption/desorption isotherms of the TiO2 powder shows that the specific surface area of the TiO2 spheres is 82 m2/g, which is slightly

Nanostructured, mesoporous Au/TiO₂ model catalysts – structure, stability and catalytic properties

• Matthias Roos,
• Dominique Böcking,
• Kwabena Offeh Gyimah,
• Gabriela Kucerova,
• Joachim Bansmann,
• Johannes Biskupek,
• Ute Kaiser,
• Nicola Hüsing and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 593–606, doi:10.3762/bjnano.2.63

• (BET) relation in the p/p0 range of 0.05 to 0.3 [26]. The pore size distribution was evaluated from the desorption branch of the isotherms, by the procedure developed by Barrett, Joyner and Halenda (BJH) [27]. XRD measurements were performed on a PANalytical MPD PRO instrument, with Cu Kα radiation (λ

Inorganic–organic hybrid materials through post-synthesis modification: Impact of the treatment with azides on the mesopore structure

• Miriam Keppeler,
• Jürgen Holzbock,
• Johanna Akbarzadeh,
• Herwig Peterlik and
• Nicola Hüsing

Beilstein J. Nanotechnol. 2011, 2, 486–498, doi:10.3762/bjnano.2.52

• evaluated by nitrogen sorption and small angle X-ray scattering (SAXS) analyses. Figure 2 shows the nitrogen adsorption/desorption isotherms at 77 K for modified silica gels before and after nucleophilic substitution (SiO2–(CH2)1,3–Cl → SiO2–(CH2)1,3–N3). The isotherms for the chloroalkyl-containing

• precursor materials are of type IV with H2 hysteresis loops according to the classification of Sing et al. [31], whereas the same samples after conversion of the chlorides into azides display hysteresis loops of H1 type indicating a narrow distribution of pores. In addition, the isotherms for SiO2–(CH2)1,3

• –N3 exhibit stretching along the volume axis, adsorption and desorption isotherms display a sharper capillary condensation step and the relative pressure of the pore filling is shifted to larger values compared to the corresponding SiO2–(CH2)1,3–Cl. These variations in the hysteresis loops indicate an

Novel acridone-modified MCM-41 type silica: Synthesis, characterization and fluorescence tuning

• Maximilian Hemgesberg,
• Gunder Dörr,
• Yvonne Schmitt,
• Andreas Seifert,
• Zhou Zhou,
• Robin Klupp Taylor,
• Sarah Bay,
• Stefan Ernst,
• Markus Gerhards,
• Thomas J. J. Müller and
• Werner R. Thiel

Beilstein J. Nanotechnol. 2011, 2, 284–292, doi:10.3762/bjnano.2.33

• with our expectations. Table 1 summarizes the values obtained for the described MCM-41-sample as well as for both Sc(III)-free and Sc(III)-containing MCM-ACR. The type IV BET isotherms of the material exhibit a large slope in the N2 uptake only at lower p/p0 ratios, and they show no significant

• CHNS vario Microcube elemental analyzer (Elementar). X-ray powder diffraction (PXRD) patterns of the silica samples were recorded on a Siemens D5005 instrument using Ni-filtered Cu Kα radiation (λ = 1.5404 Å), with a step size of 1 °/min. N2-Adsorption–desorption isotherms, pore size distributions as

Pore structure and surface area of silica SBA-15: influence of washing and scale-up

• Jörg P. Thielemann,
• Frank Girgsdies,
• Robert Schlögl and
• Christian Hess

Beilstein J. Nanotechnol. 2011, 2, 110–118, doi:10.3762/bjnano.2.13

• shape of the isotherms of sample 1 (Figure 1) is almost ideally type-IV and no change of the hysteresis was observed with the different washing procedures. This means that the homogeneity and order of the hexagonal pores were not altered by washing. The surface area and the pore volume of the untreated

• × batch and calcined at 550 °C. The half size batches were then washed with linearly scaled up amounts of solvent based on material weight and also calcined at 550 °C. Interestingly, the BET isotherms of the 1× half batch (Figure 8), which was obtained by dividing the 9× batch into smaller factions, shows

• of 2C. Furthermore, the peak broadening of 3C is much lower as in case of 2C. Comparison of the desorption branches of the isotherms of the extensively washed samples 3C, 3D, 3E (Figure 8) revealed that with increasing batch size the bulge at relative pressure 0.45 decreases and the surface area

Synthesis of LiNbO₃ nanoparticles in a mesoporous matrix

• Anett Grigas and
• Stefan Kaskel

Beilstein J. Nanotechnol. 2011, 2, 28–33, doi:10.3762/bjnano.2.3

• . Elemental analyses of these materials showed that there was no silica residue after the treatment. Figure 2 shows the nitrogen physisorption isotherms of the SBA-15 and LiNbO3/SBA-15 composite (LN), and the corresponding pore size distributions of the samples. The measurements were recorded to investigate

• samples, nitrogen adsorption–desorption curves show type IV isotherms with hysteresis loops, which is typical for mesoporous solids, suggesting that the ordered structure remains intact after LiNbO3 loading. Furthermore, the isotherms show a significant reduction of the specific BET surface area from 729

• taken into account based on LaB6 reference measurements. Small-angle X-ray diffraction patterns were recorded on a Bruker AXS Nanostar. The nitrogen physisorption isotherms at 77 K were measured using a Quantachrome Autosorb 1C. The samples were pre-treated at 150 °C for 3 h in vacuum (10−6 bar). The