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

• synthesized by hydrothermal treatment of a glucose solution yielding carbon spheres with sizes of 330 ± 50 nm, followed by nitrogen doping via heat treatment in ammonia atmosphere. The influence of a) varying the nitrogen doping temperature (550–1000 °C) and b) of a catalytic graphitization prior to nitrogen

• are chemical vapor deposition (CVD) and arc discharge methods for N-doped graphene, graphite, and carbon nanotubes [9]. Most commonly, the post-synthetic approach is carried out by thermal treatment of carbon in ammonia atmosphere, typically leading to surface N-doping. A variety of N bonding

• . Annealing graphene oxide (GO) in an ammonia atmosphere at 550 °C led to pyridinic N-doped graphene, while at a temperature of 850 °C graphitic nitrogen coexisted with pyridinic nitrogen, and for higher temperatures the amount of graphitic N increased. Annealing GO at 850 °C in the presence of polyaniline or

pH-Controlled fluorescence switching in water-dispersed polymer brushes grafted to modified boron nitride nanotubes for cellular imaging

• Saban Kalay,
• Yurij Stetsyshyn,
• Volodymyr Donchak,
• Khrystyna Harhay,
• Ostap Lishchynskyi,
• Halyna Ohar,
• Yuriy Panchenko,
• Stanislav Voronov and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2019, 10, 2428–2439, doi:10.3762/bjnano.10.233

• under acidic conditions [42]. In our previous work [12], we have reported a two-step method for preparation of a responsive surface layer on oligoperoxide-functionalized BNNTs, where amino groups on BNNTs form at the ends and defects. Additional amine groups can be easily introduced with ammonia plasma

• -dependent fluorescence properties. Third, acrylic groups in P(AA-co-FA) can be easy modified for drugs and/or targeting agents similar to that reported in [61]. It is well known that the carboxyl group of acrylic acid can react with ammonia to form acrylamide, or with an alcohol to form an acrylate ester

Coating of upconversion nanoparticles with silica nanoshells of 5–250 nm thickness

• Cynthia Kembuan,
• Maysoon Saleh,
• Bastian Rühle,
• Ute Resch-Genger and
• Christina Graf

Beilstein J. Nanotechnol. 2019, 10, 2410–2421, doi:10.3762/bjnano.10.231

• followed by a stepwise growth of these particles without a purification step, where in each step equal volumes of tetraethyl orthosilicate and ammonia water are added, while the volumes of cyclohexane and the surfactant Igepal® CO-520 are increased so that the ammonia water and surfactant concentrations

• microemulsion method. The Stöber method refers to the process of preparing silica via the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) within an alcohol–ammonia–water system [25]. Related methods are widely used for coating NPs that are dispersible in polar media [26][27]. Modified Stöber

• name Igepal® CO-520) and distributed in the continuous nonpolar phase [44]. The ratio between the aqueous components and the surfactant determines the size of these droplets [30], which act as nanoreactors. For the polycondensation of precursors such as TEOS, ammonia usually acts as a catalyst [43

Synthesis of highly active ETS-10-based titanosilicate for heterogeneously catalyzed transesterification of triglycerides

• Muhammad A. Zaheer,
• David Poppitz,
• Khavar Feyzullayeva,
• Marianne Wenzel,
• Jörg Matysik,
• Radomir Ljupkovic,
• Aleksandra Zarubica,
• Alexander A. Karavaev,
• Andreas Pöppl,
• Roger Gläser and
• Muslim Dvoyashkin

Beilstein J. Nanotechnol. 2019, 10, 2039–2061, doi:10.3762/bjnano.10.200

The influence of porosity on nanoparticle formation in hierarchical aluminophosphates

• Matthew E. Potter,
• Lauren N. Riley,
• Alice E. Oakley,
• Panashe M. Mhembere,
• June Callison and
• Robert Raja

Beilstein J. Nanotechnol. 2019, 10, 1952–1957, doi:10.3762/bjnano.10.191

• porosity. Specifically, we compare three known methods for nanoparticle preparation, incipient wetness (IW), wet impregnation (WI) and ammonia evaporation (AE), on the typical microporous (MP-SAPO-5) and corresponding hierarchically porous system (HP-SAPO-5) [15][16]. MP-SAPO-5 was synthesised according to

Upcycling of polyurethane waste by mechanochemistry: synthesis of N-doped porous carbon materials for supercapacitor applications

• Christina Schneidermann,
• Pascal Otto,
• Desirée Leistenschneider,
• Sven Grätz,
• Claudia Eßbach and
• Lars Borchardt

Beilstein J. Nanotechnol. 2019, 10, 1618–1627, doi:10.3762/bjnano.10.157

• to 670 m2·g−1 and to 0.27 cm3·g−1, while the nitrogen content increases to 6.3 wt % (Table 1). This observation is related to an intensified chemical activation process due to the high amount of urea and the formation of ammonia during the high-temperature treatment, leading to a higher consumption

• of carbon and its partial textural destruction. In addition to the formation of ammonia and the activation of the carbon, urea can form (NH4)2(CO3), which further decomposes to gaseous H2O, CO2 and NH3 and leads to additional porosity of the carbon. In order to attenuate the activation process, while

High-temperature resistive gas sensors based on ZnO/SiC nanocomposites

• Vadim B. Platonov,
• Marina N. Rumyantseva,
• Alexander S. Frolov,
• Alexey D. Yapryntsev and
• Alexander M. Gaskov

Beilstein J. Nanotechnol. 2019, 10, 1537–1547, doi:10.3762/bjnano.10.151

• semiconductor materials: where CO(gas), NH3(gas) are molecules of carbon monoxide and ammonia in the gas phase, is a particle of chemisorbed oxygen, e− is an electron released into the conduction band; CO2(gas), N2(gas), H2O(gas) are the molecules of the reaction products desorbed from the surface of the

Selective gas detection using Mn₃O₄/WO₃ composites as a sensing layer

• Yongjiao Sun,
• Zhichao Yu,
• Wenda Wang,
• Pengwei Li,
• Gang Li,
• Wendong Zhang,
• Lin Chen,
• Serge Zhuivkov and
• Jie Hu

Beilstein J. Nanotechnol. 2019, 10, 1423–1433, doi:10.3762/bjnano.10.140

• between the two metal oxides. The sensor based on the Mn3O4/WO3 composite with 3 atom % Mn showed a high selective response to hydrogen sulfide (H2S), ammonia (NH3) and carbon monoxide (CO) at working temperatures of 90 °C, 150 °C and 210 °C, respectively. The demonstrated superior selectivity opens the

• surface oxygen species and conduction band, finally resulting in a higher response. However, an excess amount of Mn3O4 has a negative influence on the response of the gas sensor because of the decrease of the effective reaction areas between WO3 and ammonia molecules [36]. Ultimately, we found that the 3

• atom % Mn3O4/WO3 composites have the best ammonia sensing performance. Conclusion In summary, WO3 and Mn3O4/WO3 composites with different concentrations of Mn were prepared and characterized. Their selective gas sensing properties were investigated, and the measurement results show that the gas sensors

Gas sensing properties of individual SnO₂ nanowires and SnO₂ sol–gel nanocomposites

• Alexey V. Shaposhnik,
• Dmitry A. Shaposhnik,
• Sergey Yu. Turishchev,
• Olga A. Chuvenkova,
• Stanislav V. Ryabtsev,
• Alexey A. Vasiliev,
• Xavier Vilanova,
• Francisco Hernandez-Ramirez and
• Joan R. Morante

Beilstein J. Nanotechnol. 2019, 10, 1380–1390, doi:10.3762/bjnano.10.136

• sensor response due to the unlikelihood of sample recrystallization. The results from the ammonia detection experiments showed that the ratio of the sensor response to the surface area exhibits similar values for both the individual nanowire and nanopowders-based sensor materials. Keywords: gas sensors

• Virgili (Tarragona, Spain). The preliminary results concerning this publication were discussed at Eurosensors conferences [32][33]. The present work presents a comparative study of the material properties of SnO2 devices prepared by different methods and by using ammonia as a reference gas for the

• assessment of their sensing characteristics. The use of ammonia in recent works is due to the strong interest in this gas as a marker for stomach diseases and to our collaboration with a company producing suitable measurement instruments in Russia (St. Petersburg). Experimental Material synthesis and

A silver-nanoparticle/cellulose-nanofiber composite as a highly effective substrate for surface-enhanced Raman spectroscopy

• Yongxin Lu,
• Yan Luo,
• Zehao Lin and
• Jianguo Huang

Beilstein J. Nanotechnol. 2019, 10, 1270–1279, doi:10.3762/bjnano.10.126

• Silver nitrate (AgNO3), β-ᴅ-glucose and concentrated ammonia were bought from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China); sodium hydrate (NaOH) was purchased from Shanghai Titanchem Co., Ltd. (Shanghai, China); Rhodamine 6G (R6G, 98.5%) was obtained from J&K Chemical Ltd. (Shanghai, China

Green fabrication of lanthanide-doped hydroxide-based phosphors: Y(OH)₃:Eu³⁺ nanoparticles for white light generation

• Tugrul Guner,
• Anilcan Kus,
• Mehmet Ozcan,
• Aziz Genc,
• Hasan Sahin and
• Mustafa M. Demir

Beilstein J. Nanotechnol. 2019, 10, 1200–1210, doi:10.3762/bjnano.10.119

• degrades into ammonia that acts as hydroxide source. In this study, HMTA was replaced with LiOH, and Y(OH)3:Eu3+ crystals were obtained through the interaction of OH− ions released from LiOH with Y3+ ions from the yttrium source in water at room temperature. Even at 5 min, Y(OH)3:7.5% Eu3+ crystals were

• process where there is more time to act on these particular crystals. The crystal growth mechanism is summarized and illustrated in Scheme 1. Compared to HMTA, which decomposes into ammonia and releases OH− ions slowly, LiOH is able to give OH− ions through complete dissociation directly to the reaction

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• for the removal of ammonia from wastewater (Table 1) [161]. Also, TiO2–ZnO@clay nanoarchitectures derived from a smectite (Cloisite®30B) have been also prepared by sol–gel reactions involving the delamination of the silicate. The resulting materials show good photocatalytic activity for the

CuInSe₂ quantum dots grown by molecular beam epitaxy on amorphous SiO₂ surfaces

• Henrique Limborço,
• Pedro M.P. Salomé,
• Rodrigo Ribeiro-Andrade,
• Jennifer P. Teixeira,
• Nicoleta Nicoara,
• Kamal Abderrafi,
• Joaquim P. Leitão,
• Juan C. Gonzalez and
• Sascha Sadewasser

Beilstein J. Nanotechnol. 2019, 10, 1103–1111, doi:10.3762/bjnano.10.110

• passivation layer was deposited on top of the samples. CdS was deposited by conventional chemical bath deposition (CBD) with a solution of 1.1 M ammonia, 0.100 M thiourea, and 0.003 M cadmium acetate [36]. The solution is mixed in a beaker at room temperature, and the samples are immersed into the beaker

Scavenging of reactive oxygen species by phenolic compound-modified maghemite nanoparticles

• Małgorzata Świętek,
• Yi-Chin Lu,
• Rafał Konefał,
• Liliana P. Ferreira,
• M. Margarida Cruz,
• Yunn-Hwa Ma and
• Daniel Horák

Beilstein J. Nanotechnol. 2019, 10, 1073–1088, doi:10.3762/bjnano.10.108

• functional groups. In this study, magnetite (Fe3O4) nanoparticles were synthetized by coprecipitation of iron(II) chloride and iron(III) chloride with ammonia and subsequently oxidized with hydrogen peroxide under mild acidic conditions. The resulting maghemite (γ-Fe2O3) has the benefit of higher chemical

Synthesis of MnO₂–CuO–Fe₂O₃/CNTs catalysts: low-temperature SCR activity and formation mechanism

• Yanbing Zhang,
• Lihua Liu,
• Yingzan Chen,
• Xianglong Cheng,
• Chengjian Song,
• Mingjie Ding and
• Haipeng Zhao

Beilstein J. Nanotechnol. 2019, 10, 848–855, doi:10.3762/bjnano.10.85

• reducibility is lower compared with that of 4% MnO2–CuO–Fe2O3/CNTs. Ammonia temperature-programmed desorption analysis The chemisorption and activation of NH3 on the surface acid sites of a catalyst are generally viewed as the primary processes in the SCR of NO. Therefore, ammonia temperature-programmed

Hydrophilicity and carbon chain length effects on the gas sensing properties of chemoresistive, self-assembled monolayer carbon nanotube sensors

• Juan Casanova-Cháfer,
• Carla Bittencourt and
• Eduard Llobet

Beilstein J. Nanotechnol. 2019, 10, 565–577, doi:10.3762/bjnano.10.58

• candidates for integration into different types of transducers such as chemoresistors, resonant gravimetric or field effect devices, only to cite a few applications. Bare carbon nanotubes have been employed to detect gases such as nitrogen dioxide [7], ammonia [8], oxygen [9] or ethanol [10]. However

Ceria/polymer nanocontainers for high-performance encapsulation of fluorophores

• Kartheek Katta,
• Dmitry Busko,
• Yuri Avlasevich,
• Katharina Landfester,
• Stanislav Baluschev and
• Rafael Muñoz-Espí

Beilstein J. Nanotechnol. 2019, 10, 522–530, doi:10.3762/bjnano.10.53

• , ≥99.0%) acrylic acid (AA, Sigma-Aldrich, 99%), hexadecane (Sigma-Aldrich, 99.0%), tetrahydrofuran (THF, Sigma-Aldrich, ≥99.9%), cerium(III) nitrate hexahydrate (Sigma-Aldrich, 99.99%), sodium hydroxide (Sigma-Aldrich, ≥97.0%), ammonia solution (28% aqueous solution, VWR), sodium dodecyl sulfate (SDS

• , the pH value of the dispersion was adjusted to pH 10 with a 28% ammonia solution. Then 5 mmol of metal salt per gram of dispersion nanocapsules was added and the dispersion was stirred for 2 h to allow for the binding of cerium ions to the surface of the capsules. Cerium(III) nitrate hexahydrate was

Site-specific growth of oriented ZnO nanocrystal arrays

• Rekha Bai,
• Dinesh K. Pandya,
• Sujeet Chaudhary,
• Veer Dhaka,
• Vladislav Khayrudinov,
• Jori Lemettinen,
• Christoffer Kauppinen and
• Harri Lipsanen

Beilstein J. Nanotechnol. 2019, 10, 274–280, doi:10.3762/bjnano.10.26

• and trisodium citrate as additional reagents to grow the twinned ZnO NCs. The growth method they adopted involves multiple steps and is quite time consuming as zinc acetate dihydrate and ammonia solution containing citrates is initially kept at 90 °C for one hour in a Teflon-lined autoclave and

Wet chemistry route for the decoration of carbon nanotubes with iron oxide nanoparticles for gas sensing

• Hussam M. Elnabawy,
• Juan Casanova-Chafer,
• Badawi Anis,
• Mostafa Fedawy,
• Mattia Scardamaglia,
• Carla Bittencourt,
• Ahmed S. G. Khalil,
• Eduard Llobet and
• Xavier Vilanova

Beilstein J. Nanotechnol. 2019, 10, 105–118, doi:10.3762/bjnano.10.10

• CNTs and iron oxide have been also used for sensing ammonia and NOx [22][23]. Among those gases NO2 is considered one of the most dangerous air pollutants occurring both indoors, due to using of gas stoves, and outdoors from fuel powered motor vehicles and power plants especially in long-term exposure

Colloidal chemistry with patchy silica nanoparticles

• Pierre-Etienne Rouet,
• Cyril Chomette,
• Laurent Adumeau,
• Etienne Duguet and
• Serge Ravaine

Beilstein J. Nanotechnol. 2018, 9, 2989–2998, doi:10.3762/bjnano.9.278

• nanoparticles; valence; Introduction The molecular world is essentially based on the covalent bonding of atoms displaying valences of 1, 2 (sp), 3 (sp2), 4 (sp3) and, to a lesser extent, 5 (sp3d) and 6 (sp3d2). The molecules of water, ammonia and methane, in which the valence orbitals of the central atom adopt

• %), methacryloxypropylyltriethoxysilane (MPS, Aldrich, 98%), (3-aminopropyl)triethoxysilane (APTES, Aldrich, 99%), triethylamine (TEA, Sigma-Aldrich, 99%), sodium persulfate (Sigma-Aldrich, 99%), Symperonic® NP30 (Aldrich), sodium dodecylsulfate (SDS, Sigma-Aldrich, >90%), tetraethoxysilane (TEOS, Sigma-Aldrich, 99%), ammonia (30% in

• under continuous magnetic stirring with a solution of deionized water and ammonia, at a volume ratio of 93.8/5/1.2 for absolute ethanol, water and ammonia, respectively. 18.3 μL of TEOS were added and the reaction mixture was stirred for 12 h at 20 ± 2 °C. Upon completion of the growth of silica shell

Ternary nanocomposites of reduced graphene oxide, polyaniline and hexaniobate: hierarchical architecture and high polaron formation

• Claudio H. B. Silva,
• Maria Iliut,
• Christopher Muryn,
• Christian Berger,
• Zachary Coldrick,
• Vera R. L. Constantino,
• Marcia L. A. Temperini and
• Aravind Vijayaraghavan

Beilstein J. Nanotechnol. 2018, 9, 2936–2946, doi:10.3762/bjnano.9.272

• sonication (less than 10 μm) [34][35][42][43][44][67]. Reduced graphene oxide was prepared by chemical reduction of GO in 0.25 mg·mL−1 dispersions with hydrazine and ammonia solution at 25 °C for 7 days. The resulting rGO dispersion presents suitable stability for the preparation of the nanocomposites. This

Layered calcium phenylphosphonate: a hybrid material for a new generation of nanofillers

• Kateřina Kopecká,
• Ludvík Beneš,
• Klára Melánová,
• Vítězslav Zima,
• Petr Knotek and
• Kateřina Zetková

Beilstein J. Nanotechnol. 2018, 9, 2906–2915, doi:10.3762/bjnano.9.269

• (PhP), calcium chloride (CaCl2), ammonia solution, propan-2-ol (all Sigma-Aldrich); CHS-EPOXY 520 (Spolchemie, a. s., Czech Republic) – a low molecular weight epoxy resin based on bisphenol A; Jeffamine D230 and Jeffamine D2000 (Huntsman International LLC) – polyether amines were used. BYK 9076 – an

• concentrated aqueous ammonia solution. Then, 50 mL of CaCl2 solution (5.5 g, 5 × 10−2 mol) was added: a) at once (sample denoted as CaPhP_a); b) "drop by drop" (CaPhP_d); and c) in several portions (CaPhP_s). A white precipitate was formed immediately in all cases. Then, the reaction mixture was diluted by 50

• mL of distilled water and stirred at medium speed (≈250 rpm) for 30 minutes. The precipitate formed was collected by filtration, washed with water until neutral pH to remove the remaining ammonia, and dried at room temperature. To obtain a fine powder it was possible to grind dried material in a

Graphene-enhanced metal oxide gas sensors at room temperature: a review

• Dongjin Sun,
• Yifan Luo,
• Marc Debliquy and
• Chao Zhang

Beilstein J. Nanotechnol. 2018, 9, 2832–2844, doi:10.3762/bjnano.9.264

• affected the sensor at low humidity levels. However, the response of the composite sensor increased with increasing humidity at high humidity levels. At low humidity levels, ammonia and water molecules competed for adsorption, which reduces the sensing performance of NH3. As humidity levels increased

• , ammonia adsorbed on the surface of sensor by dissolving into water, leading to the higher response. This is quite different from the usual opinion that sensitivity will decrease at high humidity levels. Zhang et al. [47] synthesized CuO nanoflowers via hydrothermal method, then CuO and rGO were deposited

Improved catalytic combustion of methane using CuO nanobelts with predominantly (001) surfaces

• Qingquan Kong,
• Yichun Yin,
• Bing Xue,
• Yonggang Jin,
• Wei Feng,
• Zhi-Gang Chen,
• Shi Su and
• Chenghua Sun

Beilstein J. Nanotechnol. 2018, 9, 2526–2532, doi:10.3762/bjnano.9.235

• are needed to improve the thermal stability of such nanostructures as they tend to aggregate after high temperature treatment. Experimental Synthesis of CuO nanowires and nanobelts For a typical sample, 1 g of Cu(NO3)2 was dissolved in 100 mL distilled water and 30 mL ammonia solution (NH3·H2O, 0.15

Droplet-based synthesis of homogeneous magnetic iron oxide nanoparticles

• Christian D. Ahrberg,
• Ji Wook Choi and
• Bong Geun Chung

Beilstein J. Nanotechnol. 2018, 9, 2413–2420, doi:10.3762/bjnano.9.226

• solution was an aqueous solution of 4 M ammonia (Alfa Aesar, USA). The solutions were separately injected through the two fused silica capillaries of the droplet generator using syringe pumps with identical flowrates. Mineral oil (M5904, Sigma-Aldrich USA) with 0.075 vol % Triton X-100 (Samchun Chemical

• reaction and in our droplet device. In droplet synthesis and in batch synthesis, mixing of the iron chloride precursor solution with the ammonia leads to the immediate formation of a dark brown precipitate. For both methods, the same reagent concentrations and reaction times were chosen. Following both