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

• configurations were used as a material to fabricate supercapacitor electrodes. These nanofibers were synthesized by applying a modified parallel electrode to the electrospinning method (MPEM) in order to generate electrospun polyacrylonitrile (PAN) nanofibers containing graphene. After synthesis, these fibers

• surface area of CGCNFs, thereby significantly increasing their specific capacitance. In addition, the ordering of CGCNFs within the electrode improved the electron transfer efficiency, resulting in a higher specific capacitance. Keywords: carbon/graphene composite nanofibers; carbonization

• ; electrochemistry; electrode material; electrospinning method; ordered and porous nanofibers; supercapacitor; Introduction As the technology sector develops, societal demands for energy storage devices also increases. Supercapacitors, including electric double-layer capacitors (EDLCs) and pseudo-capacitance

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

• of MnTUPCl, which is a sufficient amount to sustain the reactions for weeks, at least in principle. However, since we propose that the reduction of the manganese porphyrins takes place when they are adsorbed to the negatively biased electrode, their adsorption–desorption process must be dynamic. Once

• solvated by the 1-phenyloctane solvent and migrate to the other electrode (vide infra). Second, in a counter reaction they are oxidized to chlorine gas. No net current would be observed if one of the two processes would not occur. In order to check the proposed role of the chloride ions, an analogous

• of these complications may be eliminated by adding a third, reference electrode to the setup and by using a conducting electrolyte (so that it turns into a so-called electrochemical (EC) STM [20][21]). At the same time, the absence of an electrolyte, which typically contains a high concentration of

Ultrasensitive detection of cadmium ions using a microcantilever-based piezoresistive sensor for groundwater

• Dinesh Rotake,
• Anand Darji and
• Nitin Kale

Beilstein J. Nanotechnol. 2020, 11, 1242–1253, doi:10.3762/bjnano.11.108

• disadvantages during operation in water when the refractive index of water changes [30][31]. Many authors have proposed electrode-based approaches for the selective sensing of Cd(II) [32], but the limits of detection were always in the micromolar to nanomolar ranges. Some of the authors used fluorescent [5][33

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

• negative electrode [9]. We herein refer to HCs as strongly disordered carbons (having a high fraction of sp3-hybridized defects or heteroatoms), independent of their graphitizability. After the introduction of the LIB, efforts in research and development on sodium-ion anodes, i.e., lithium-analogue

• market share of HC and graphite was still 52% and 43%, respectively, and today graphite is almost exclusively used as negative electrode material in commercial LIBs [11]. Graphite with an interlayer distance of 0.335 nm cannot be intercalated by sodium without solvent co-intercalation [9][12][13

• decomposition at potentials below the stability window of the electrolyte (for LIBs typically around 0.8 VLi) [21]. Since the dielectric SEI passivates the electrode, an irreversible capacity proportional to the electrochemical active surface area is expected. Accordingly, the reduction of the specific surface

Thermophoretic tweezers for single nanoparticle manipulation

• Jošt Stergar and
• Natan Osterman

Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97

• refraction between the particle and the surrounding solvent is also required. For manipulation of smaller particles and molecules, typically, electrophoretic [4] and electrokinetic [5] forces are used, but they need sophisticated electrode geometries. A combination of optical tweezers and an array of

Monolayers of MoS₂ on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

• Asieh Yousofnejad,
• Gaël Reecht,
• Nils Krane,
• Christian Lotze and
• Katharina J. Franke

Beilstein J. Nanotechnol. 2020, 11, 1062–1071, doi:10.3762/bjnano.11.91

• in a scanning tunneling microscope, requires a metal electrode. To (partially) preserve the molecular properties the molecule–electrode coupling has to be properly designed. An elegant way is to clamp the molecule between electrodes via single-atom bonds at opposing sites of the molecule while the

Excitonic and electronic transitions in Me–Sb₂Se₃ structures

• Nicolae N. Syrbu,
• Victor V. Zalamai,
• Ivan G. Stamov and
• Stepan I. Beril

Beilstein J. Nanotechnol. 2020, 11, 1045–1053, doi:10.3762/bjnano.11.89

• to the illuminated electrode and it decreases to zero when a negative voltage is applied. The nature of the photoelectric effect cannot be associated with the contact-EMF effect since there is no band bending at the semiconductor surface region. On the other hand, the photo-EMF effect, in this case

A new photodetector structure based on graphene nanomeshes: an ab initio study

• Babak Sakkaki,
• Hassan Rasooli Saghai,
• Ghafar Darvish and
• Mehdi Khatir

Beilstein J. Nanotechnol. 2020, 11, 1036–1044, doi:10.3762/bjnano.11.88

• Green’s functions and α is the lowest and highest self-energies due to coupling to the electrodes. The current at the electrode α (left to right) with spin σ is calculated using [28][29]: The following relation determines the effective crossing coefficients [30]: To investigate and compare photodetectors

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

• in a Teflon cell with the 0.2 cm2 area exposed to the electrolyte. The electrolytes used in this study were 1.75 M NaCl and 1 M HNO3. The experiments were performed in a three-electrode configuration, with a Pt mesh with a surface area of 6 cm2 acting as counter electrode, a saturated Ag/AgCl

• reference electrode and the sample as working electrode. The anodization was performed in galvanostatic as well as potentiostatic regimes at room temperature (T = 23 °C). Analysis of morphology and chemical composition of the anodized GaAs crystals was carried out using scanning electron microscopy (Zeiss

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

• , Universitetskii pr. 26, 198504 St. Petersburg, Russia 10.3762/bjnano.11.79 Abstract We provide a direct comparison of two distinct methods of Ti felt surface treatment and Pt/Ir electrocatalyst deposition for the positive electrode of regenerative fuel cells and vanadium–air redox flow batteries. Each method is

• of some RFBs (such as the vanadium–air RFB). The positive electrode of these devices has to perform the challenging OER and ORR on one material system. A bimetallic Pt/Ir electrocatalyst is used most commonly as it provides minimal overpotentials under strongly acidic conditions [3][8][9][10]. The

• methods [12] as well as particles of various sizes [13] and shapes [14]. However, each study is presented as a self-sufficient piece of work with limited critical comparison to the state of the art. The conditions under which electrochemical performance is quantified (electrode substrate, electrolyte

Templating effect of single-layer graphene supported by an insulating substrate on the molecular orientation of lead phthalocyanine

• K. Priya Madhuri,
• Abhay A. Sagade,
• Pralay K. Santra and
• Neena S. John

Beilstein J. Nanotechnol. 2020, 11, 814–820, doi:10.3762/bjnano.11.66

• materials [10][11]. A single-layer of graphene can serve as a transparent conducting electrode and function as donor or acceptor when combined with suitable organic counterparts [12][13]. However, graphene itself is supported on a rigid substrate for device integration and, hence, it is important to

• the PbPc layer is sandwiched between the conductive graphene layer, which served as a bottom electrode, and the Cr/Au tip (diameter < 35 nm and k = 0.18 N·m−1, MikroMasch, USA), serving as a top electrode. Chemical structure of lead phthalocyanine. (a) Top view and (b) side view of a Pb(II)Pc molecule

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

• group of Prof. Fan, Co3O4/CTF1-700-1:1 has been studied as ORR catalyst and showed a half-wave potential of 0.84 V vs a reversible hydrogen electrode (RHE) [20]. Kamiya et. al. synthesized a Pt-atom-modified CTF hybridized with conductive carbon nanoparticles and used it as an ORR catalyst [36]. The

• /CTF-1-400-20, whereas 7 atom % N is involved in bonding to Ni for Ni/CTF-1-600-22. Electrochemical catalysis In order to investigate the activity of the synthesized materials in the OER, rotating disc electrode (RDE) experiments were conducted in 1 mol/L KOH solution in a three-electrode cell. Figure

• confirm the reproducibility. The obtained materials were designated as Ni/CTF-1-400-X and Ni/CTF-1-600-X, where X represents the weight percentage of nickel in the composite materials according to AAS. Electrochemical measurements A three-electrode cell was used for the electrochemical measurements on a

Structural optical and electrical properties of a transparent conductive ITO/Al–Ag/ITO multilayer contact

• Aliyu Kabiru Isiyaku,
• Ahmad Hadi Ali and
• Nafarizal Nayan

Beilstein J. Nanotechnol. 2020, 11, 695–702, doi:10.3762/bjnano.11.57

• indium metal is needed [9][10][11]. The insertion of a metal layer reduces the transparency of the ITO electrode due to opaqueness of the metal, but selecting an optimal metal thickness can effectively decrease the reflection from the metal film and thus enhance the transmittance. Furthermore, it gives

• of an ITO sandwich electrode with Ag alloy against heat treatment at 450 °C was carried out by Roh et al. [30]. An appreciable durability and stability of the Ag films was observed. In the present work, the structural, optical and electrical properties of an Al–Ag bilayer between ITO layers (ITO/Al

A novel dry-blending method to reduce the coefficient of thermal expansion of polymer templates for OTFT electrodes

• Xiangdong Ye,
• Bo Tian,
• Yuxuan Guo,
• Fan Fan and
• Anjiang Cai

Beilstein J. Nanotechnol. 2020, 11, 671–677, doi:10.3762/bjnano.11.53

• Telecommunications, Xi’an 710121, China 10.3762/bjnano.11.53 Abstract Among the patterning technologies for organic thin-film transistors (OTFTs), the fabrication of OTFT electrodes using polymer templates has attracted much attention. However, deviations in the electrode alignment occur because the coefficient of

• silver target of 60 × 5 mm in size and purity of 99.99% as the OTFT electrode material was purchased from ZHNOGNUO New Material Co., Ltd., (Beijing, China). Pentacene as the semiconductor layer was used as purchased from Sigma-Aldrich and dissolved to a concentration of 5% in 1,2-dichlorobenzene

• gate and source–drain through a printing process [3][23]. The same experiment was performed using the 20 wt % wet-blended template, as shown in Figure 6. Figure 6a shows the electrode alignment of the PDMS/SiO2 composite template (20 wt %) prepared via wet blending. There are deviations in the

Exfoliation in a low boiling point solvent and electrochemical applications of MoO₃

• Matangi Sricharan,
• Bikesh Gupta,
• Sreejesh Moolayadukkam and
• H. S. S. Ramakrishna Matte

Beilstein J. Nanotechnol. 2020, 11, 662–670, doi:10.3762/bjnano.11.52

• , the MoO3 dispersion in 2-butanone retains its intrinsic nature even after exposure to sunlight for 24 h. The composites of MoO3 nanosheets were used as an electrode material for supercapacitors and showed a high specific capacitance of 201 F·g−1 in a three-electrode configuration at a scan rate of 50

• was not altered after exposure to sunlight (UV radiation) for 24 h. The exfoliated MoO3 was used as electrode material for supercapacitor applications. The specific capacitance values were as high as 221 F·g−1 at 5 mV·s−1 with good rate capability and capacitance retention in a three-electrode system

• Zetasizer NanoZS. All electrochemical measurements were carried out using Autolab PGSTAT302N. Electrode preparation and electrochemical testing Three-electrode system: A glassy carbon electrode (GCE, 0.3 cm diameter) as the working electrode, Pt wire as counter electrode and a saturated calomel electrode

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

• characterization The ESM analysis was conducted inside of particles of the cross-sections of the fresh and aged cathodes. Two examples of the cross-section structure of the cathodes are given in Figure 1. In Figure 1a the fresh and in 1b the aged cathode cross-section is shown. The electrode consists of particles

• the aged full cell after cycling. Due to the anode contribution to the capacity loss in the commercial full cell setup, the cathode was additionally analysed separately. The cathode ageing is observed in the Nyquist plot in Figure S2 from the fresh and aged cathode vs lithium metal reference electrode

• in a three-electrode test cell. More information about the experimental setup is given in Supporting Information File 1. Following the approach proposed in the literature, the first semi-circle at high frequencies is assigned to the cathode and the second semi-circle at mid frequencies to the lithium

Electrochemically derived functionalized graphene for bulk production of hydrogen peroxide

• Munaiah Yeddala,
• Pallavi Thakur,
• Anugraha A and
• Tharangattu N. Narayanan

Beilstein J. Nanotechnol. 2020, 11, 432–442, doi:10.3762/bjnano.11.34

• , and hence their economic viability for the future technologies is highly questionable [10][24][25][26][27]. Hence new metal-free electrode materials for H2O2 generation are highly sought after for future technologies. Recently, carbon-based catalysts have emerged as an alternate material for existing

• electrolyte concentration also determines the extent of functionalization of graphene. The presence of the C=O groups is further confirmed by cyclic voltammetry (CV) measurements in alkaline and acidic electrolyte. The CV profiles of the EEG samples (EEG-modified glassy carbon electrode (GCE) as the working

• electrode in a three-electrode set up) in the acidic and alkaline medium between −0.2 to 1.2 V vs RHE at 100 mV/s scan rate are shown in Figure 2. Two distinct features observed in the CV profiles are: the difference in the area under the curve of the different EEG samples, which indicates the difference in

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• drain electrode of the transistor. In a later study, Schumacher et al. [24] used optical pumping in a pp-KPFM approach to probe the photocarrier lifetime in GaAs samples grown at low temperature. In organic BHJ solar cells, electron donor and acceptor materials are processed to form two interpenetrated

• of the photocarriers [36]. We now focus on the photoresponse of the phase-segregated organic blend, i.e., the photoactive layer of the device without the cathode electrode, given by configuration 2 in Figure 3b. The surface morphology of the PTB7:PC71BM blend (Figure 7a) is consistent with that

• levels of holes and electrons upon illumination, symbolized by dotted lines. (b) Organic BHJ solar cell and experimental configuration. The sample is illuminated in backside geometry. The transparent anode, the hole collecting electrode made of indium tin oxide coated with PEDOT:PSS, is grounded. The

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

• the NiMoO4@Co3O4/CA ternary composite as the positive electrode and activated carbon as the negative electrode. The ASC device exhibits a large capacitance of 125.4 F/g at 0.5 A/g, a maximum energy density of 34.1 Wh/kg at a power density of 208.8 W/kg as well as a good cyclic stability (84% after

• ), the capacitance of which originates from the electrostatic adsorption of reversible ions at the electrode/electrolyte interface, and pseudocapacitors, for which the capacitance arises from reversible Faradaic reactions correlating with electroactive species [7][8]. Compared to EDLCs, pseudocapacitors

• can provide a much higher specific capacitance as a result of rapid reversible redox reactions [9][10]. Recently, advanced electrode materials based on transition metal molybdates such as NiMoO4 [11], CoMoO4 [12], MnMoO4 [13] and FeMoO4 [14] with suitable oxidation states and unique electrochemical

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• Kondo temperature. In a recent study, the thermoelectric properties of a noninteracting QD coupled to massless Dirac fermions have been analyzed using the EOM technique [38]. At low temperature, by tuning the voltage of the metallic gate electrode, this QD system reaches large values of thermopower and

• heterostructure consisting of a two dimensional electron gas. The energy of the confined electrons can be changed using a gate electrode [30]. The Coulomb repulsion energy in the QD is assumed to be U ≈ 480 meV, i.e., U/D = 0.069, an acceptable value for magnetic impurities in graphene [56][57][58]. To estimate

• between the nonequilibrium Kondo resonances is equal to the difference of the values of the chemical potentials, eV = Δμ. The suppression of the peak amplitudes is caused by the dissipative transitions of electrons between the electrode of high chemical potential and the electrode of low chemical

Molecular architectonics of DNA for functional nanoarchitectures

• Debasis Ghosh,
• Lakshmi P. Datta and
• Thimmaiah Govindaraju

Beilstein J. Nanotechnol. 2020, 11, 124–140, doi:10.3762/bjnano.11.11

• of the advantages of this system was that the DNA–multichromophore organization could be aligned vertically over the gold electrode, which facilitated exothermic charge separation and suppressesed the ground-state charge transfer (CT) complexation between DPP and NDI, followed by the generation of a

• photocurrent (Figure 7b). However, the randomly assembled array of DPPNDI–dT40 immobilized across the gold electrode was unable to generate any photocurrent response owing to ground-state CT complexation of DPP with NDI in their random arrangement (Figure 7c). Tanaka, Ono, and co-workers reported the

Nanosecond resistive switching in Ag/AgI/PtIr nanojunctions

• Botond Sánta,
• Dániel Molnár,
• Patrick Haiber,
• Agnes Gubicza,
• Edit Szilágyi,
• Zsolt Zolnai,
• András Halbritter and
• Miklós Csontos

Beilstein J. Nanotechnol. 2020, 11, 92–100, doi:10.3762/bjnano.11.9

• ][27] have been promoted in terms of the “atomic switch” by K. Terabe et al. utilizing Ag2S as the ionic conductor medium [28]. The roles of the matrix, the electrode, and their interfaces in the filament formation have been extensively investigated covering a broad range of materials systems [4

• memristor was determined numerically as Vbias = Vdrive − I·RS. As a polarity convention, a positive bias corresponds to a higher potential applied on the planar Ag electrode with respect to the PtIr tip. A representative I(V) trace acquired within 400 ms is exemplified in Figure 1a. Bipolar resistive

Simple synthesis of nanosheets of rGO and nitrogenated rGO

• Pallellappa Chithaiah,
• Madhan Mohan Raju,
• Giridhar U. Kulkarni and
• C. N. R. Rao

Beilstein J. Nanotechnol. 2020, 11, 68–75, doi:10.3762/bjnano.11.7

• voltammetry and CD experiments with three-electrode system using 1 M H2SO4 as electrolyte (Figure 8). CV curves of rGO and H-rGO at different scan rates from 5 to 200 mV·s−1 vs Hg/Hg2SO4 are shown in Figure 8a and Figure 8b, respectively. These curves show increase in current density with decreasing scan rate

• , respectively. We have checked the rate capability of the working electrode at different scan rates of 10, 20, 40, 60, 80, 100, and 200 mV·s−1 and observed that the specific capacitance values were 96, 64, 43, 35, 30, 27 and 19 F·g−1, respectively (Figure 8c). For comparison, the charge–discharge (CD) curves

• stability (Figure 9). We compared our result with other materials reported recently (Table 1). For conductivity measurements, the H-rGO sample was dispersed in ethanol and drop-cast on a gold gap electrode. The average resistance measured using a Keithley source meter is ca. 4 MΩ. The corresponding

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

• measurements under controlled electrolyte transport, employing a rotating ring disk electrode (RRDE) setup (section 2 in “Results and Discussion”). We will compare the ORR performance with those of the previously reported TiON@NCS and TaON@NCS composite materials. A more detailed account of the electrochemical

• resolution of 5 cm−1 (50 µm slit-like pinhole) with an exposure time of 5 s (10 accumulations). Electrode preparation and electrochemical measurements The catalyst thin-film electrode (catalyst loading of 0.285 mg·cm−2 for Pt-free catalyst, 140 μg·cm−2 loading (Pt loading: 28 μg·cm−2) for the 20 wt % Pt/C E

• a N2 stream. With these loadings we could form homogeneous, thin and stable catalyst layers on the electrode. The resulting film was covered with the same volume of a 1 wt % aqueous Nafion solution and dried again to ensure the mechanical stability of the catalyst layer on the glassy carbon without

Antimony deposition onto Au(111) and insertion of Mg

• Lingxing Zan,
• Da Xing,
• Abdelaziz Ali Abd-El-Latif and
• Helmut Baltruschat

Beilstein J. Nanotechnol. 2019, 10, 2541–2552, doi:10.3762/bjnano.10.245

• ) electrolyte into/from a Sb-modified electrode shows a positive shift (400 mV) of the onset potential of Mg deposition compared to that of a bare Au electrode. From the charge of the Mg deposition, we find that the ratio of Mg to Sb is 1:1, which is somewhat less than expected for the Mg3Sb2 alloy. Keywords

• electrodeposited Bi0.88Sb0.12 alloy by Arthur et al. [7]. However, the capacity declines to 215 mAh/g after 100 cycles with an electrolyte mixture of ethylmagnesium chloride, diethylaluminum chloride and anhydrous THF. A detailed, fundamental study of magnesium deposition/dissolution at a Sb-modified Au electrode

• deposition on a Au electrode was carried out by Jung [8], who found that antimony deposition on Au(100) and Au(111) in acid electrolyte undergoes two electrochemical processes involving an irreversible adsorption and underpotential deposition. This irreversible adsorption was attributed to oxygenous Sb(III