A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• has been used to induce the growth of semiconductor nanowires [97]. In this study by Aramesh, gold catalyst nanoparticles were distributed onto GaAs and InAs substrates and upon irradiating selected regions with helium ions, semiconductor nanowires grew from the gold nucleation sites. By increasing

Nanoporous and nonporous conjugated donor–acceptor polymer semiconductors for photocatalytic hydrogen production

• Zhao-Qi Sheng,
• Yu-Qin Xing,
• Yan Chen,
• Guang Zhang,
• Shi-Yong Liu and
• Long Chen

Beilstein J. Nanotechnol. 2021, 12, 607–623, doi:10.3762/bjnano.12.50

• , studies regarding the long-term stability of CPs are still needed. (Left) Schematic diagram of the mechanism of semiconducting catalyst-mediated photocatalytic hydrogen production (CB: conduction band, VB: valence band, SED: sacrificial electron donors). (Right) Charge separation in a CP-based

Stability and activity of platinum nanoparticles in the oxygen electroreduction reaction: is size or uniformity of primary importance?

• Kirill O. Paperzh,
• Anastasia A. Alekseenko,
• Vadim A. Volochaev,
• Ilya V. Pankov,
• Olga A. Safronenko and
• Vladimir E. Guterman

Beilstein J. Nanotechnol. 2021, 12, 593–606, doi:10.3762/bjnano.12.49

• composition and structure of the catalytic layers, and the catalysts themselves [9]. Platinum–carbon catalysts, whose composition and structure determine their functional characteristics, are the key components of MEA catalytic layers. Of particular importance is the study of the catalyst electrochemical

• behavior in the ORR, since it is at the cathode that strong polarization and pronounced degradation of the catalyst take place. Such а degradation occurs as a result of both the operation at high anodic potentials and the effect of aggressive oxygen-containing intermediates, which are formed during the

• . Kinoshita was one of the first researchers to obtain such results [12]. As a first approximation, the specific activity of platinum in the catalyst, being referred to the unit mass of the metal Imass (mass activity), is determined as a product of the electrochemically active surface area (ESA) and the

The preparation temperature influences the physicochemical nature and activity of nanoceria

• Robert A. Yokel,
• Wendel Wohlleben,
• Johannes Georg Keller,
• Matthew L. Hancock,
• Jason M. Unrine,
• D. Allan Butterfield and
• Eric A. Grulke

Beilstein J. Nanotechnol. 2021, 12, 525–540, doi:10.3762/bjnano.12.43

• exposed to during preparation may contribute to the dissolution rate difference. Industrially formed nanoceria is often calcined, that is, exposed to temperatures of 400 °C and more. This is appropriate for nanoceria used as a combustion catalyst, as the calcined surface can become quite active when

Boosting of photocatalytic hydrogen evolution via chlorine doping of polymeric carbon nitride

• Malgorzata Aleksandrzak,
• Michalina Kijaczko,
• Wojciech Kukulka,
• Daria Baranowska,
• Martyna Baca,
• Beata Zielinska and
• Ewa Mijowska

Beilstein J. Nanotechnol. 2021, 12, 473–484, doi:10.3762/bjnano.12.38

• pairs, (iv) improved photogenerated charge transport and separation, and (v) higher reducing ability of the photogenerated electrons. The above factors affected the 4.4-fold enhancement of the photocatalytic efficiency in hydrogen evolution in comparison to the pristine catalyst. Keywords: chlorine

• structure allows for the catalyst to have a higher specific surface area and more active sites, which can simultaneously promote mass transfer and charge separation in nanodomains, thus optimizing the π-conjugated system for photochemical applications [40][41]. Furthermore, elemental mapping of nitrogen

• the H2 evolution rate after three cycles, indicating the stability of the catalyst. Table 4 presents a comparative study of Cl-PCN with catalysts doped with Cl and other elements which have been reported in the literature. The table presents a broad range of the enhancement factor of the hydrogen

Spontaneous shape transition of Mn_xGe_1−x islands to long nanowires

• S. Javad Rezvani,
• Luc Favre,
• Gabriele Giuli,
• Yiming Wubulikasimu,
• Isabelle Berbezier,
• Augusto Marcelli,
• Luca Boarino and
• Nicola Pinto

Beilstein J. Nanotechnol. 2021, 12, 366–374, doi:10.3762/bjnano.12.30

• obtained via chemical methods [28][29] or via vapor–solid–liquid (VLS) and, less frequently, vapor–solid–solid (VSS) mechanisms. A metallic droplet (liquid or solid) acts as a catalyst, in chemical vapor deposition (CVD), or as a seed, in molecular beam epitaxy (MBE), for the NW growth [7][30][31]. By

• using these techniques, NWs are grown away from the substrate, usually in a tilted direction, and size distribution and geometry strongly depend on the growth dynamics [32][33]. Furthermore, it is known that the catalyst introduces uncontrolled and unwanted contamination inside the crystal lattice of

• the wires. For instance, Au, generally used as catalyst for the growth of various semiconductor NWs, acts as a deep-level trap in germanium bulk and NWs, modifying the electronic transport properties [5]. Strain-induced elongation is a mechanism [34] that can lead to either epitaxial or endotaxial

Free and partially encapsulated manganese ferrite nanoparticles in multiwall carbon nanotubes

• Saja Al-Khabouri,
• Salim Al-Harthi,
• Toru Maekawa,
• Mohamed E. Elzain,
• Ashraf Al-Hinai,
• Ahmed D. Al-Rawas,
• Abbsher M. Gismelseed,
• Ali A. Yousif and
• Myo Tay Zar Myint

Beilstein J. Nanotechnol. 2020, 11, 1891–1904, doi:10.3762/bjnano.11.170

• ) carbon, (e) manganese, (f) iron, (g) nickel (the source of Ni is the original MWCNTs used as catalyst), and (h) overlays of MnFe2O4/MWCNTs. The arrows in (a) and (b) are pointing at MWCNTs layers, which are coating the partially encapsulated nanoparticles. (i–l) The majority of the MnFe2O4 nanoparticles

Towards 3D self-assembled rolled multiwall carbon nanotube structures by spontaneous peel off

• Jonathan Quinson

Beilstein J. Nanotechnol. 2020, 11, 1865–1872, doi:10.3762/bjnano.11.168

• smaller inner diameter [16]. Thus, the size of a catalyst to grow a N-MWCNT is larger than that to grow an undoped C-MWCNT. This size is determined by the experimental conditions, such as the presence or absence of N atoms. This is related to the fact that smaller nanoparticles are more difficult to be

• . For the synthesis performed, a size increase is relatively easy to be achieved since ferrocene, source of the iron atoms, is constantly provided (see Experimental section). However, a size decrease is possible mainly by a size change of the catalyst nanoparticle and by some “loss” of the catalyst (e.g

• is suggested (Figure 5). This schematic representation is based on the experimental results of a confirmed root-growth mechanism, on the relationship between the size of the catalyst particle, and on the diameter of MWCNTs and N-MWCNTs. In addition, it is in agreement with [6][12][16][20][21][24][26

Unravelling the interfacial interaction in mesoporous SiO₂@nickel phyllosilicate/TiO₂ core–shell nanostructures for photocatalytic activity

• Bridget K. Mutuma,
• Xiluva Mathebula,
• Isaac Nongwe,
• Bonakele P. Mtolo,
• Boitumelo J. Matsoso,
• Rudolph Erasmus,
• Zikhona Tetana and
• Neil J. Coville

Beilstein J. Nanotechnol. 2020, 11, 1834–1846, doi:10.3762/bjnano.11.165

• [24][25]. One method to maximize the SiO2–TiO2 interaction is via the synthesis of core–shell nanostructures or nanocomposites [18][19][26][27]. Ikeda et al. [26] reported an improved photodecomposition of acetic acid by using a titania core@hollow silica shell nanostructured catalyst. Similarly, Ren

• surface [23]. Thus, silica-based core–shell nanocomposites offer added advantages of manipulating the pore structure, surface area, morphology, and catalyst reactivity [28]. Unlike the metal oxide–metal oxide composites, the use of metal oxide core@metal nanocomposites as dopants for titania

• NiPS with a sheet-like morphology, which was then used as a catalyst for the hydrogenation of styrene. More recently, Ghiat et al. [39] reported on the photocatalytic properties of nickel phyllosilicates for hydrogen production. Their nickel phyllosilicate, displaying a surface area of 95 m2·g−1, was

Nanocasting synthesis of BiFeO₃ nanoparticles with enhanced visible-light photocatalytic activity

• Thomas Cadenbach,
• Maria J. Benitez,
• A. Lucia Morales,
• Cesar Costa Vera,
• Luis Lascano,
• Francisco Quiroz,
• Alexis Debut and
• Karla Vizuete

Beilstein J. Nanotechnol. 2020, 11, 1822–1833, doi:10.3762/bjnano.11.164

• photocatalytic activity [20]. Since the photocatalytic degradation of organic molecules using a metal oxide photocatalyst is a heterogeneous process, it is obvious that efficiency and overall catalytic performance are strongly correlated to the number of active sites on the catalyst surface area and, thus, to

• = 5 mg/L) was mixed with 50 mg of the BiFeO3 sample. The mixture was stirred for 60 min in darkness to ensure an adsorption–desorption equilibrium between the catalyst and the dye solution. After irradiation, aliquots were taken every 30 min and centrifuged in darkness at 5000 rpm for 3 min to

• separate the catalyst powder from the solution. The absorbance of each sample during photocatalysis was measured at the maximum absorption peak of RhB. Characterization techniques and equipment The structure and phase purity of the nanomaterials synthesized here were characterized using powder X-ray

Self-standing heterostructured NiC_x-NiFe-NC/biochar as a highly efficient cathode for lithium–oxygen batteries

• Shengyu Jing,
• Xu Gong,
• Shan Ji,
• Linhui Jia,
• Bruno G. Pollet,
• Sheng Yan and
• Huagen Liang

Beilstein J. Nanotechnol. 2020, 11, 1809–1821, doi:10.3762/bjnano.11.163

• [26]. For instance, molybdenum/tungsten carbide with a well-defined nanostructure was synthesized via a hydrothermal method, and the obtained metal carbide catalyst yielded a high capacity in lithium–oxygen batteries [15]. Also, titanium carbide was synthesized by Bruce et al. as cathode material for

• PANalytical B.V. Empyean X-ray diffractometer with Cu Kα radiation (λ = 1.5406 Å). The surface morphology of the film catalyst was studied via scanning electron microscopy (SEM) on a Carl Zeiss Ultra Plus scanning electron microscope. Transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), and

• surface of the catalyst particles. These undecomposed Li2O2 might be attributed to the formation of crystalline Li2O2, which is probably the main reason for the observed decline in the specific capacity (Figure 6c). To identify the product formed on the surface of NiFe-PBA/PP-900 after charge and

PEG/PEI-functionalized single-walled carbon nanotubes as delivery carriers for doxorubicin: synthesis, characterization, and in vitro evaluation

• Shuoye Yang,
• Zhenwei Wang,
• Yahong Ping,
• Yuying Miao,
• Yongmei Xiao,
• Lingbo Qu,
• Lu Zhang,
• Yuansen Hu and
• Jinshui Wang

Beilstein J. Nanotechnol. 2020, 11, 1728–1741, doi:10.3762/bjnano.11.155

• were afterwards conjugated with PEG and PEI. The typical procedure is as follows: An amount of 100 mg of CNTs-COOH was redispersed in 50 mL of distilled water and ultrasonically treated for 1 h. EDC·HCl (500 mg) and NHS (500 mg), used as catalyst, were added into the mixture under stirring at 45 °C

Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action

• Matías Guerrero Correa,
• Fernanda B. Martínez,
• Cristian Patiño Vidal,
• Camilo Streitt,
• Juan Escrig and
• Carol Lopez de Dicastillo

Beilstein J. Nanotechnol. 2020, 11, 1450–1469, doi:10.3762/bjnano.11.129

• stabilizer or protective agent [42]. Occasionally, a catalyst can be added to accelerate the reaction, as well as a solvent, which can favor the interaction of the chemicals. As an example, we highlight the work of Wang et al. in which well-dispersed spherical nanoparticles with sizes ranging from 20 to 80

Wafer-level integration of self-aligned high aspect ratio silicon 3D structures using the MACE method with Au, Pd, Pt, Cu, and Ir

• Mathias Franz,
• Romy Junghans,
• Paul Schmitt,
• Adriana Szeghalmi and
• Stefan E. Schulz

Beilstein J. Nanotechnol. 2020, 11, 1439–1449, doi:10.3762/bjnano.11.128

• fabrication uses cost-efficient subprocesses and omits expensive processes such as nanopatterning with high-resolution lithography. One low-cost method for the fabrication of such high aspect ratio templates and structures is metal-assisted chemical etching (MACE). This process uses a noble metal catalyst

• comparably as catalyst [23]. Chartier et al. [13] reported the etching mechanisms of the MACE process. The cathodic reaction is the reduction of H2O2 at the noble metal interface within an acidic solution. This reduction transfers an electron to the H+ ion and produces a hole (an electron vacancy) h+: The

• analysed by Fazio et al. [1]. It is mainly based on multiple light scattering at the silicon nanowires. Figure 4 shows SEM images of an etched wafer using Au nanoparticles as etching catalyst. This wafer has been etched with 50 mmol/L H2O2 for 10 min. The SEM images show cross sections of the wafer centre

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

• agglomeration (i.e., highly porous supports) [16]. After years of development, conventional synthesis methods still have problems meeting the requirements for scalability of the synthesis and long-term stability of the resulting catalyst. In this work, we report on a novel one-step synthesis approach that not

• , and Pt-NPs with a mean particle diameter less than 3 nm and a narrow particle size distribution (PSD) with a geometric standard deviation of 1.24–1.3 can be achieved. Furthermore, the NP immobilization within the carbon support significantly improves the long-term stability of the catalyst, as shown

• Supporting Information File 1, Table S2). In principle, a higher degree of oxidation of the catalyst could also be realized by introducing additional oxygen to the plasma via gas injection; however, oxygen is also known to influence the resulting CNW morphology [18][19]. At moderate Pt loading (7.6 wt

Analysis of catalyst surface wetting: the early stage of epitaxial germanium nanowire growth

• Owen C. Ernst,
• Felix Lange,
• David Uebel,
• Thomas Teubner and
• Torsten Boeck

Beilstein J. Nanotechnol. 2020, 11, 1371–1380, doi:10.3762/bjnano.11.121

Role of redox-active axial ligands of metal porphyrins adsorbed at solid–liquid interfaces in a liquid-STM setup

• Thomas Habets,
• Sylvia Speller and
• Johannes A. A. W. Elemans

Beilstein J. Nanotechnol. 2020, 11, 1264–1271, doi:10.3762/bjnano.11.110

• at room temperature. We found that while the porphyrin catalyst MnTUPCl (tetrakis-meso-undecylporphyrin manganese(III) chloride, Figure 1a) is fully inert in n-tetradecane solution, it becomes catalytically active in the epoxidation of alkenes when it is adsorbed at the interface of a Au(111

• added salts, allows us to pinpoint the behavior of the axial ligand of our catalyst in the non-polar liquid in which also our catalysis studies were carried out. Still, our system shows several of the characteristics of a conventional electrochemical cell. Apart from the bias dependency of the reaction

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• polarizations of Raman scattering and the photoluminescence from the tip–sample nanogap. Results and Discussion Silicon nanowire core–shell morphology In accordance with the VLS synthesis method (see Experimental section), the utilized Pt catalyst, or finally PtxSiy, remains at the tip of the nanowire during

• grains with different orientation. Furthermore, catalyst migration along the SiNW backbone was observed in some cases (Figure 1c). Although the SiNWs grown by the VLS mechanism possess are crystalline, the silicon shells deposited onto the nanowires by thermal CVD (here using a temperature of 520 °C) can

• of the nanowire exhibits an amorphous morphology. Confocal optical microscopy of silicon nanowires As the first step, core–shell SiNWs grown with a platinum catalyst [29] are characterized using a custom-built confocal optical microscope. Figure 2a shows the representative geometry of these SiNWs

Gas-sensing features of nanostructured tellurium thin films

• Dumitru Tsiulyanu

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

• sensing parameters did not differ much from the similar parameters obtained earlier for microcrystalline Te films. Further investigations have been extended to Te nanotubes grown on quartz or Si(111) substrates through a catalyst-free growing process in a furnace filled with argon [21]. Another study used

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

• well documented in the literature, and this paper provides a direct comparison under identical experimental conditions of electrochemical measurements and in identical units. In the first method, based on classical engineering, the bimetallic catalyst is deposited by dip-coating in a precursor solution

• different types are not possible. The goal of the present paper is to provide such a direct comparison between two very distinct preparation methods of bimetallic Pt/Ir electrocatalysts. For both catalyst types, we will consider one electrode substrate (titanium felt) [15], one electrolyte (0.5 M H2SO4 at

• consider here two distinct catalyst preparation methods. As a standard method used in the engineering context, we perform an acid etch of the titanium fibers (to generate surface roughness and thereby increase the specific surface area), followed by dip-coating of a noble metal salt precursor solution on

Transition from freestanding SnO₂ nanowires to laterally aligned nanowires with a simulation-based experimental design

• Jasmin-Clara Bürger,
• Sebastian Gutsch and
• Margit Zacharias

Beilstein J. Nanotechnol. 2020, 11, 843–853, doi:10.3762/bjnano.11.69

• substrates were prepared by two different preparation methods for the catalyst seeds, which are required for the VLS process. As a catalyst material, gold was chosen. First, a-plane sapphire substrates with structured gold thin films (thickness 5 nm) by metal evaporation, and second, a-plane sapphire

• controllers for individual adjustment of the introduced volumetric flow of the carrier gas, Ar, and the process gas, O2. The gas outlet is connected to a pumping system for base pressure evacuation and process pressure control. The samples, which were previously covered with catalyst, were arranged in the

• ]. The droplets compete for the tin atoms and oxygen molecules [30]. This results in a locally reduced material concentration in the surrounding area of the catalyst-decorated samples. As seen from the simulations of the volumetric flow (Figure 2), an increased volumetric flow will result in a reduced

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

• method. CTF-1-600 and Ni/CTF-1-600 show high catalytic activity towards OER and a clear activity for the electrochemical oxygen reduction reaction (ORR). Ni/CTF-1-600 requires 374 mV overpotential in OER to reach 10 mA/cm2, which outperforms the benchmark RuO2 catalyst, which requires 403 mV under the

• developed. Noble metals (Ir, Ru) and their oxides are the current commercial electrocatalysts for the OER, whereas Pt metal is the benchmark catalyst for the ORR [4][5]. Yet, all these catalysts have drawbacks such as scarcity and high cost, which are disadvantageous for their large-scale production and

• 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

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• , it can be considered a hybrid 1D and 2D material. In [116], commercially available BNNTs were fabricated using a catalyst-free high-temperature pressure method, and the laser heating method was studied in terms of SPEs. Non-treated BNNTs provided photostable SPEs down to the single nanotube, either

Effect of Ag loading position on the photocatalytic performance of TiO₂ nanocolumn arrays

• Jinghan Xu,
• Yanqi Liu and
• Yan Zhao

Beilstein J. Nanotechnol. 2020, 11, 717–728, doi:10.3762/bjnano.11.59

• of the 1D TiO2–Ag nanostructures prepared to date are Ag-nanoparticle-coated TiO2 (ACT), in which the catalytic efficiency of the catalyst is greatly decreased when the Ag loading is increased to a certain extent. Wang et al. [29] used the hydrothermal method to prepare an array of TiO2 nanocolumns

• the catalyst, so the catalyst needs to have a certain adsorption capacity for dye molecules. Due to the presence of oxygen vacancies, the surface of TiO2 is usually negatively charged and has a good adsorption capacity for cationic dye molecules [36]. Commonly used cationic dyes are rhodamine, methyl

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

• regarded to be very effective and attractive because of its operation under mild conditions and no need of oxidant, active catalyst, and irradiation [8][9]. Therefore, adsorption with carbon nanotubes, activated carbon (AC), biomass, and metallic–organic frameworks (MOFs) has been actively studied for the