Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

• Deborah Vidick,
• Xiaoxing Ke,
• Michel Devillers,
• Claude Poleunis,
• Arnaud Delcorte,
• Pietro Moggi,
• Gustaaf Van Tendeloo and
• Sophie Hermans

Beilstein J. Nanotechnol. 2015, 6, 1287–1297, doi:10.3762/bjnano.6.133

• microscopy (HRTEM) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) confirms their bimetal nature on the nanoscale. The obtained bimetal nanoparticles supported on nanocarbon were tested as catalysts in ammonia synthesis and are shown to be active at low temperature

• and atmospheric pressure with very low Ru loading. Keywords: ammonia synthesis; cluster; nanofibers; nanoparticles; nanotubes; Introduction Metal nanoparticles (NPs) supported on nanoscopic forms of carbon (nanotubes, nanofibers) are an important class of nanostructured materials that find

• agglomeration, and in particular, their characterization at atomic resolution to prove their bimetal nature within individual nanoparticles. In order to test their potential application in catalysis, the carbon-supported nanoparticles are evaluated in ammonia synthesis, as a reference reaction with mature

Electrocatalysis on the nm scale

• R. Jürgen Behm

Beilstein J. Nanotechnol. 2015, 6, 1008–1009, doi:10.3762/bjnano.6.103

• theoretical description of important electrocatalytic reactions, such as hydrogen evolution/water splitting [4][5] or electrocatalytic ammonia synthesis [6]. Additionally, mechanistic studies of electrocatalytic reactions, such as O2 reduction [7], CO oxidation [8] or the electrooxidation of small organic

Pt- and Pd-decorated MWCNTs for vapour and gas detection at room temperature

• Hamdi Baccar,
• Atef Thamri,
• Pierrick Clément,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2015, 6, 919–927, doi:10.3762/bjnano.6.95

• known to weakly interact with VOCs in general and with aromatic VOCs in particular. Therefore, a functionalisation of the carbon nanotube sidewalls is essential to promote sensitivity. In previous works, we used oxygen-plasma-treated multiwalled carbon nanotubes for detecting nitrogen dioxide, ammonia

• , hydrogen sulphide, ammonia and hydrogen [28]. However, this technique leads to an inhomogeneous decoration of the carbon nanotubes with high irregularities in the shape and size of the metal nanoparticles, which eventually may result in poor sensor reproducibility. Espinosa and co-workers decorated plasma

A simple approach to the synthesis of Cu_1.8S dendrites with thiamine hydrochloride as a sulfur source and structure-directing agent

• Xiaoliang Yan,
• Sha Li,
• Yun-xiang Pan,
• Zhi Yang and
• Xuguang Liu

Beilstein J. Nanotechnol. 2015, 6, 881–885, doi:10.3762/bjnano.6.90

• temperature [4]. Polycrystalline Cu1.8S powder was prepared by mechanical alloying and subsequent spark plasma sintering and it exhibited excellent thermoelectric properties as a p-type sulfide [5]. An aqueous ammonia assisted approach was developed for the synthesis of Cu1.8S with triangular and rod-like

Transformation of hydrogen titanate nanoribbons to TiO₂ nanoribbons and the influence of the transformation strategies on the photocatalytic performance

• Melita Rutar,
• Nejc Rozman,
• Matej Pregelj,
• Carla Bittencourt,
• Romana Cerc Korošec,
• Andrijana Sever Škapin,
• Aleš Mrzel,
• Srečo D. Škapin and
• Polona Umek

Beilstein J. Nanotechnol. 2015, 6, 831–844, doi:10.3762/bjnano.6.86

• morphology or on the surface appearance of the nanoribbons. The transformations performed in the reductive atmosphere, an NH3(g)/Ar(g) flow, and in the ammonia solution led to nitrogen doping. The nitrogen content increased with an increasing calcination temperature, as was determined by X-ray photoelectron

• processing time required for complete conversion in the hydrothermal reactor, in deionized water at 160 °C (CH-W), was 10 h. In contrast, the transformation in 0.5 M NH3(aq) (CH-N) was only completed after 24 h. In addition, the experiments in ammonia solutions with higher molarities did not produce any TiO2

• suspensions decreases with the decreasing pH. This is in the agreement with our results since the transformation occurred only with 0.5 M NH3(aq) and not in ammonia solutions with larger molarities. Also the time needed for the complete transformation in the basic environment was significantly longer (24 h

Nanoparticle shapes by using Wulff constructions and first-principles calculations

• Georgios D. Barmparis,
• Zbigniew Lodziana,
• Nuria Lopez and
• Ioannis N. Remediakis

Beilstein J. Nanotechnol. 2015, 6, 361–368, doi:10.3762/bjnano.6.35

• ammonia-synthesis catalyst from first principles [47][48][49]. Density functional calculations were used to obtain accurate surface energies for several faces of hcp Ru. These values were used in a standard Wulff-construction software to create the polyhedron that corresponded to the equilibrium shape. In

• ). Microscopy and/or first-principles simulations are typically used to identify what the active sites for each catalytic reaction are. For example, B-type step atoms are the only active sites for ammonia synthesis on Ru-based catalysts [56]. Atomistic Wulff constructions can be then used to calculate the

Synthesis, characterization, monolayer assembly and 2D lanthanide coordination of a linear terphenyl-di(propiolonitrile) linker on Ag(111)

• Zhi Chen,
• Svetlana Klyatskaya,
• José I. Urgel,
• David Écija,
• Olaf Fuhr,
• Willi Auwärter,
• Johannes V. Barth and
• Mario Ruben

Beilstein J. Nanotechnol. 2015, 6, 327–335, doi:10.3762/bjnano.6.31

• of the resulting aldehydes with ammonia giving the final product 2 with a overall yield of 18% [45] (Scheme 1). Additionally, a small amount of a byproduct, identified as terphenyl-4-propiolonitrile (3) (Ph3–C≡C–C≡N), was separated and revealed to be a thus-far unreported decarboxylation reaction of

• (m/z): [M]+ calcd for C24H18O2, 338.1; found, 338.0. 3,3'-([1,1':4',1''-terphenyl]-4,4''-diyl)dipropiolonitrile (2) Following [45] a 2 M solution of ammonia in 2-propanol (1.8 mL, 3.2 mmol) and anhydrous magnesium sulfate (1.5 g, 12.8 mmol) were added to a stirred solution of compound 5 (203 mg, 0.6

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

• . The most commonly preferred chemical functionalization is through the –OH on B atoms and –NH2 groups at the edges and defects, as shown in Figure 3 [15][44][63][64][65]. In one study, BNNTs were functionalized with amine groups by ammonia plasma irradiation [63]. It was predicted that NH2∙ radicals

SERS and DFT study of copper surfaces coated with corrosion inhibitor

• Maurizio Muniz-Miranda,
• Francesco Muniz-Miranda and
• Stefano Caporali

Beilstein J. Nanotechnol. 2014, 5, 2489–2497, doi:10.3762/bjnano.5.258

• adsorbed species on the metal surface. In order to obtain a suitable surface roughness from a smooth copper substrate, etching in nitric acid was performed (as previously demonstrated [17]), followed by immersion in ammonia solution. The reducing environment limits the oxidation of the copper surface

• (which takes place very quickly) in order to preserve the metallic nanostructures necessary for the SERS activation by removing oxides by formation of water-soluble complexes with ammonia. Next, the copper plate was immersed in a solution of 1,2,4-triazole, which acts as a corrosion inhibitor by

• isolating the metallic surface from the oxidative action of the atmosphere. Conclusion An etching process was performed on smooth copper surfaces using nitric acid followed by immersion in an ammonia solution, resulting in SERS-active substrates. This activation was validated by the SEM and profilometry

Synthesis and characterization of fluorescence-labelled silica core-shell and noble metal-decorated ceria nanoparticles

• Rudolf Herrmann,
• Markus Rennhak and
• Armin Reller

Beilstein J. Nanotechnol. 2014, 5, 2413–2423, doi:10.3762/bjnano.5.251

• synthesis of ceria NP [38][39][40][41] and found the procedure with air oxidation of cerium(III) nitrate in ethanol/water mixtures in the presence of ammonia very convenient [42][43]. At 60–70 °C (open flask) one obtains small crystalline NP in ethanol/water 4:1 as solvent of almost spherical shape (average

Gas sensing properties of nanocrystalline diamond at room temperature

• Marina Davydova,
• Pavel Kulha,
• Alexandr Laposa,
• Karel Hruska,
• Pavel Demo and
• Alexander Kromka

Beilstein J. Nanotechnol. 2014, 5, 2339–2345, doi:10.3762/bjnano.5.243

• Figure 5, exposure of the sensor elements to 100 ppm of ammonia gas led to increased impedances from 4.4 to 5.4 MΩ and from 3.9 to 5.4 MΩ for the samples nucleated for 1 min and 5 min, respectively. It should be noted that a variation (shift) in the starting impedance value was observed. The starting

• ) for 15 min to stabilize the output characteristics. Subsequently, the specific testing gas (NH3) was injected into the chamber through the inlet port, and the change in the resistance of the sensors (dR/R) was investigated as a function of exposure time. Ammonia (NH3, quality N38, purity 99.98%) was

Nanoencapsulation of ultra-small superparamagnetic particles of iron oxide into human serum albumin nanoparticles

• Matthias G. Wacker,
• Mahmut Altinok,
• Stephan Urfels and
• Johann Bauer

Beilstein J. Nanotechnol. 2014, 5, 2259–2266, doi:10.3762/bjnano.5.235

• potassium hydroxide, 56 mM sulfuric acid, and 74 mM formic acid and pumped at an constant flow rate of 1 mL/min. The PAR reagent contained 0.55 mM 4-(2-pyridylazo)resorcinol monosodium salt monohydrate, 1 M 2-(dimethylamino)ethanol, 0.5 M aqueous ammonia solution, and 0.3 M sodium hydrogen carbonate. The

Low cost, p-ZnO/n-Si, rectifying, nano heterojunction diode: Fabrication and electrical characterization

• Vinay Kabra,
• Lubna Aamir and
• M. M. Malik

Beilstein J. Nanotechnol. 2014, 5, 2216–2221, doi:10.3762/bjnano.5.230

• ) was mixed with a 25% aqueous ammonia solution and aluminum chloride as nitrogen and aluminum sources, respectively. These were mixed in the atomic ratio of Zn:N:Al to 1:0.06:0.03 at room temperature under constant stirring. A freshly prepared tetramethylammonium hydroxide (TMAH) solution was added to

Influence of stabilising agents and pH on the size of SnO₂ nanoparticles

• Olga Rac,
• Patrycja Suchorska-Woźniak,
• Marta Fiedot and
• Helena Teterycz

Beilstein J. Nanotechnol. 2014, 5, 2192–2201, doi:10.3762/bjnano.5.228

• tetrachloride was used as a precursor and ammonia as precipitation agent) was presented by Wang et al. [16]. As a result of this reaction, an amorphous precipitate was obtained, dried and then annealed at 500 °C for 2 h. The average crystallite size of the resulting powder was 15–25 nm. The precipitation

Rapid degradation of zinc oxide nanoparticles by phosphate ions

• Rudolf Herrmann,
• F. Javier García-García and
• Armin Reller

Beilstein J. Nanotechnol. 2014, 5, 2007–2015, doi:10.3762/bjnano.5.209

• mV. DLS: 454 nm. Shell thickness (TEM) 3–6 nm. SiO2-coating of ZnO-NP [35] (sample 5) To a stirred dispersion of 5 mg of labelled ZnO-NP (sample 1) in 0.2 mL of ethanol, 90 mL of water, 5 μL of aqueous ammonia (25%) and 5 μL of tetraethoxsilane (TEOS, Sigma-Aldrich) was added. After stirring for 1 h

Influence of surface-modified maghemite nanoparticles on in vitro survival of human stem cells

• Michal Babič,
• Daniel Horák,
• Lyubov L. Lukash,
• Tetiana A. Ruban,
• Yurii N. Kolomiets,
• Svitlana P. Shpylova and
• Oksana A. Grypych

Beilstein J. Nanotechnol. 2014, 5, 1732–1737, doi:10.3762/bjnano.5.183

• modified Eagle’s medium (DMEM) was from PAA Laboratories (Pasching, Austria). Non-coated, D-mannose- and poly(N,N-dimethylacrylamide)-coated γ-Fe2O3 nanoparticles (4.4 mg/mL) were prepared through coprecipitation of FeCl2 and FeCl3 solutions with ammonia, the subsequent oxidation of the resulting product

Liquid fuel cells

• Grigorii L. Soloveichik

Beilstein J. Nanotechnol. 2014, 5, 1399–1418, doi:10.3762/bjnano.5.153

• significant amount of hydrogen such as ammonia, hydrazine, alkali metal borohydrides MBH4 (M = Na, K) are also used as fuels. Theoretically, boron-nitrogen heterocycles proposed for hydrogen storage [33][34] can be used for this purpose. In most cases the electrooxidation of fuels in fuel cells results in the

• presence of formate the oxidation potential of formic acid was shifted in the negative direction and the oxidation current increased. In this case only formic acid was oxidized. Inorganic fuel cells Direct ammonia fuel cells The nitrogen hydrides, ammonia and hydrazine, are attractive fuels for direct fuel

• cells because potentially they can be cleanly oxidized to water and nitrogen [145][146]. Ammonia cannot be used directly in acidic PEM fuel cells due to a sharp drop in membrane conductivity (ammonium salt formation) and catalysts poisoning [147]. In an early work, a fuel cell using aqueous potassium

Purification of ethanol for highly sensitive self-assembly experiments

• Kathrin Barbe,
• Martin Kind,
• Christian Pfeiffer and
• Andreas Terfort

Beilstein J. Nanotechnol. 2014, 5, 1254–1260, doi:10.3762/bjnano.5.139

• plates were immersed into ca. 0.1 mM solutions of Ellman's reagent in acetone and exposed to gaseous ammonia. Residual thiol molecules in the ethanolic solutions were indicated by formation of yellow spots. The highest dodecanethiol amount that did not lead to a color change of the TLC plates was assumed

Sublattice asymmetry of impurity doping in graphene: A review

• James A. Lawlor and
• Mauro S. Ferreira

Beilstein J. Nanotechnol. 2014, 5, 1210–1217, doi:10.3762/bjnano.5.133

• methods and techniques to achieve this have been developed to include chemical vapour deposition (CVD), using NH3 as a precursor, arc discharge [23], embedded nitrogen and carbon sources within a metal substrate [24], ion implantation [25][26], ammonia [27] or nitrogen plasma [28][29] treatments, and

• ]. They discovered that graphene grown via chemical vapour deposition (CVD) in the presence of ammonia (NH3) naturally incorporates nitrogen atoms as substitutional so-called ’graphitic’ dopants (see Figure 1A) into the crystal, and with a distinct sublattice segregation of dopants. Indeed further

• sublattice segregation, at least on local scales, was noted as a curiosity but was not discussed in depth. A key finding by the researchers was that by varying the ammonia precursor concentration they could adjust the resulting embedded dopant concentration. Further theoretical work confirmed that a tunable

Template-directed synthesis and characterization of microstructured ceramic Ce/ZrO₂@SiO₂ composite tubes

• Jörg J. Schneider and
• Meike Naumann

Beilstein J. Nanotechnol. 2014, 5, 1152–1159, doi:10.3762/bjnano.5.126

• mL of ethanol. 1mL distilled water, 1mL tetra-ethoxysilane (TEOS, TEOS, ABCR, 98%) and 2.5 mL of 25% ammonia solution were added one at a time. The obtained mixture was vigorously stirred for 6 h. The PS/silica composite fiber mats were washed with ethanol and dried at 80 °C for 12 h in an oven

Characterization and photocatalytic study of tantalum oxide nanoparticles prepared by the hydrolysis of tantalum oxo-ethoxide Ta₈(μ₃-O)₂(μ-O)₈(μ-OEt)₆(OEt)₁₄

• Subia Ambreen,
• N D Pandey,
• Peter Mayer and
• Ashutosh Pandey

Beilstein J. Nanotechnol. 2014, 5, 1082–1090, doi:10.3762/bjnano.5.121

• (μ-OEt)6(OEt)14 (1) was obtained by the controlled hydrolysis of tantalum ethoxide Ta(OEt)5 in the presence of ammonia. Compound 1 is considered as the intermediate building block in the sol–gel polymerization of Ta(OEt)5. Further hydrolysis of compound 1 yielded nanoparticles of Ta2O5, which were

• [16][17][18][19][20][21]. The present work deals with the study of the controlled hydrolysis of tantalum ethoxide in the presence of ammonia and to prepare tantalum pentaoxide nanoparticles. In this process the stable intermediate tantalum oxo-ethoxide with composition Ta8(μ3-O)2(μ-O)8(μ-OEt)6(OEt)14

• penta-ethoxide was dissolved in toluene and with the aim to examine the effect of hydrolysis in basic medium, wet ammonia gas was purged into it with continuous stirring. After 1 h at pH 8.0, a white solid was formed which was separated, re-dissolved in toluene and kept at low temperature for

Manipulation of isolated brain nerve terminals by an external magnetic field using D-mannose-coated γ-Fe₂O₃ nano-sized particles and assessment of their effects on glutamate transport

• Tatiana Borisova,
• Natalia Krisanova,
• Arsenii Borуsov,
• Roman Sivko,
• Ludmila Ostapchenko,
• Michal Babic and
• Daniel Horak

Beilstein J. Nanotechnol. 2014, 5, 778–788, doi:10.3762/bjnano.5.90

• of iron salts, namely FeCl2 and FeCl3, by rapid increase of pH by ammonia. Similarly as described in [12], this was followed by the oxidation of the resulting magnetite (Fe3O4) with sodium hypochlorite producing maghemite (γ-Fe2O3), which is chemically more stable than Fe3O4. This is in contrast to

A visible-light-driven composite photocatalyst of TiO₂ nanotube arrays and graphene quantum dots

• Donald K. L. Chan,
• Po Ling Cheung and
• Jimmy C. Yu

Beilstein J. Nanotechnol. 2014, 5, 689–695, doi:10.3762/bjnano.5.81

• for 1 h with a temperature increasing rate of 1 °C·min−1 in air was applied to improve crystallization. Synthesis of graphene quantum dots (GQDs): GQDs were synthesized from graphene oxide (GO) by heating with a solution of hydrogen peroxide and ammonia [44]. 20 mg of GO was dispersed into 5 mL of

The role of oxygen and water on molybdenum nanoclusters for electro catalytic ammonia production

• Jakob G. Howalt and
• Tejs Vegge

Beilstein J. Nanotechnol. 2014, 5, 111–120, doi:10.3762/bjnano.5.11

• V or lower for all oxygen coverages studied, and it is thus possible to (re)activate (partially) oxidized nanoclusters for electrochemical ammonia production, e.g., using a dry proton conductor or an aqueous electrolyte. At lower oxygen coverages, nitrogen molecules can adsorb to the surface and

• electrochemical ammonia production via the associative mechanism is possible at potentials as low as −0.45 V to −0.7 V. Keywords: ammonia; density functional theory; electrocatalysis; nanoparticles; oxygen poisoning; Introduction Molybdenum nanoclusters have been identified as a prime candidate for

• electrochemical ammonia production with seemingly low Faradaic losses to hydrogen evolution [1][2]. To produce ammonia electrochemically, one can either use a liquid or a solid electrolyte, but these effectively require wet conditions to obtain sufficient protonic conduction [3][4]. The presence of water may give

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

• formation induced by NaOH. Figure 7 shows the SEM images of silicas prepared by using ammonia solution (NH4OH) to induce self-assembly of LPEI with molar ratios [OH]/[EI] = 0.6, 0.8 and 3.2. We found that silica nanofilms were formed by using a molar ratio [OH]/[EI] = 0.6 (Figure 7A and Figure 7B), because

• the LPEI crystallization was delayed due to weak basicity of the ammonia solution and a low degree of deprotonation of LPEI–H+. This is consistent with the formation of silica nanofilms by using NaOH with low molar ratios [OH]/[EI]. Furthermore, when increasing the molar ratio [OH]/[EI] to 0.8, the

• similar to that synthesized by temperature-induced LPEI self-assembly (Figure 2). No peak value of the pore size distribution was observed (Figure S4 in Supporting Information File 1). To further confirm the effect of ammonia solution on the formation of silica nanostructure, the LPEI self-assembly was