bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Complex Framework Material (CFM) Hosts for Li – S Battery
Authors: Wang Louis S. , Murugavel Shanthi Pavithra , Jampani Hanumantha Prashanth , Gattu Bharat , Datta Moni Kanchan , Velikokhatnyi Oleg I , Kumta Prashant N 
Published: February 2020

Great demand for improvements in battery technology has recently been spurred by the rapidly growing personal electronics and electric vehicle industries. The search for high energy density batteries have reached a limit in lithium intercalation electrodes which have a theoretical capacity of ~250 mAh/g1. Lithium sulfur batteries are a promising alternative to intercalation chemistry batteries, as a sulfur cathode features a theoretical capacity of 1675 mAh/g2.
However, the development of lithium sulfur batteries has been impeded by two fundamental issues which are: the low conductivity of sulfur (~10-15 S/cm)3, and the dissolution of polysulfides formed during cycling4. While the conductivity issue can be mitigated by incorporating conductive carbon into the cathode, polysulfide dissolution has proven more challenging to address5
,
6. The formation and dissolution of polysulfides results in the loss of active material from the cathode which culminates in cell failure.
Previous attempts to prevent polysulfide dissolution by embedding sulfur into porous carbon structures have been moderately successful. However, the efficiency of these approaches is limited by a lack of control over porosity. To improve on these carbon structures, sulfur hosts with engineered structures and chemical properties should be developed.
In this work, lithium sulfur battery cathodes were created using complex framework materials as sulfur hosts. The cathodes were created by solution phase infiltration of sulfur into complex framework materials synthesized by microwave-assisted hydrothermal synthesis. the XRD spectrum and SEM image of one of the CFMs is shown in Figure 1. The cathodes demonstrated impressive electrochemical performance with an initial discharge capacity of ~1620 mAh/g which stabilized at 1100 mAh/g after 100 cycles.

Acknowledgement:

The authors acknowledge the financial support of DOE grant DE-EE 0006825, Edward R. Weidlein Chair Professorship funds and the Center for Complex Engineered Multifunctional Materials (CCEMM).

References:

1. F. Bidrawn, S. Lee, J. M. Vohs and R. J. Gorte, Journal of The Electrochemical Society, 2008, 155, B660-B665.
2. S. S. Zhang, Journal of Power Sources, 2013, 231, 153-162.
3. V. S. Kolosnitsyn and E. V. Karaseva, Russian Journal of Electrochemistry, 2008, 44, 506-509.
4. J.-W. Park, K. Ueno, N. Tachikawa, K. Dokko and M. Watanabe, The Journal of Physical Chemistry C, 2013, 117, 20531-20541.
5. S.-R. Chen, Y.-P. Zhai, G.-L. Xu, Y.-X. Jiang, D.-Y. Zhao, J.-T. Li, L. Huang and S.-G. Sun, Electrochimica Acta, 2011, 56, 9549-9555.
6. J. Jin, Z. Wen, G. Ma, Y. Lu and K. Rui, Solid State Ionics, 2014, 262, 170-173.

Figure 1
Silver Nanoparticle/Boron-Doped Graphene Nanoribbon Nanocomposite for Effective Surface Enhanced Raman Scattering
Authors: Li Wei Ting , Chiang Wei Hung 
Published: February 2020

Surface-enhanced Raman scattering (SERS) provides high sensitivity and selectivity on molecule detection, making it attractive for biomedical and chemical detections. Generally there are two mechanisms to influence the SERS enhancement: electromagnetic mechanism (EM) created by the metals with surface plasmon resonance (SPR) property and chemical mechanism (CM) due to the charge transfer between the molecule and the substrate. The development of synthetic method to produce nanostructures with controllable EM and CM properties will lead to important advances on both fundamental study and innovative applications for SERS-based biomedical detections. Graphene nanoribbons (GNRs) represent a unique structure of carbon nanomaterials with controlled electronic properties by tuning their widths, making them can be potentially useful as the SERS-active substrate and used in other applications including energy, composites, biomedical and electronics.
Here we report a rational design to develop a SERS-active nanocomposite with improved EM and CM properties. Toward this goal, we prepared silver (Ag)/Boron-doped GNR (B-GNR) composites using a sequential reaction route. First we synthesized GNRs with averaged width around 4 to 5 nm by the chemical unzipping of singled-walled carbon nanotubes (SWCNTs). Additionally, the prepared GNRs were doped with B atoms by a controlled carbonthemic reaction under argon (Ar) flow at atmospheric pressure and the B dopant concentration was about 1.4 atomic percentage (atom%) according to the X-ray photoelectron spectroscopy (XPS) analysis. Ag NPs with 10 nm averaged size were decorated onto the B-GNRs surface through an atmospheric-pressure microplasma-assisted redox reaction. Detailed materials characterizations including transmission electron microscopy and UV-Vis spectroscopy show that Ag/B-GNR composites were successfully synthesized in our experiment. We further systematically studied the Raman response of the Ag/B-GNR composite using Rhodamine 6G (R6G) as the Raman probe molecules. The result indicates that the Ag/GNR composite shows superior SERS performance with low detection concentration of 10-12 M of R6G and high enhance factor (EF) of 1.9x1012. We furthermore systematically studied the CM enhancement via different probing molecules and substrates. Results show that SERS performance is strongly influenced by the charge transfer mechanism induced by the energy gap between the substrate Fermi level and the LUMO energy of probing molecules. Our study provide the conception to design the applicable SERS substrates.

Figure 1
A First Principle Study of Vanadium Decorated Graphene Oxide As Novel Hydrogen Storage Material
Authors: Kureshi Sahida , Tokarev Andrey , Cannon Mark , Quan Grace , Kjeang Erik 
Published: February 2020

Transition metal functionalized graphene is good candidate for hydrogens storage material [1-3]. Transition metal atoms interact with carbon of substrate material through Dewar [4] and hydrogen molecules with Kubas [5] interaction and offer good binding energy. However due to higher cohesive energy of transition metals, synthesis of such material remains bottleneck. Boron-doping into graphene has been studied [6-8] to eliminate clustering of transition and alkali metal atoms. In this work, an alternate approach of using graphene oxide as base material is studied. Hydrogen adsorption in vanadium decorated graphene oxide is studied with density functional theory calculations based on generalized gradient approximation. The epoxyl and hydroxyl groups in graphene oxide can provide active sites for the binding of vanadium and help to mitigate the clustering problem. From the preliminary calculations, it is found that graphene oxide has very high binding energy of ~6.2 eV for vanadium, higher than the cohesive energy of vanadium (5.31 eV). Further, single vanadium atom can bind four H2 molecules with an average adsorption energy of -0.5 eV. Graphene oxide is easy to synthesis and based on the value of vanadium binding energy it is easy to decorate with vanadium. Thus, vanadium decorated graphene oxide is promising material for hydrogen storage material.
References:

Yildirim T, Ciraci S. Titanium-decorated carbon nanotubes as a potential high-capacity hydrogen storage medium. Physical review letters. 2005 May 5;94(17):175501.

Zhao Y, Kim YH, Dillon AC, Heben MJ, Zhang SB. Hydrogen storage in novel organometallic buckyballs. Physical review letters. 2005 Apr 22;94(15):155504.

Durgun E, Ciraci S, Yildirim T. Functionalization of carbon-based nanostructures with light transition-metal atoms for hydrogen storage. Physical Review B. 2008 Feb 4;77(8):085405.

Mingos DM. A historical perspective on Dewar's landmark contribution to organometallic chemistry. Journal of Organometallic Chemistry. 2001 Oct 15;635(1):1-8.

Kubas Gregory J. Molecular hydrogen complexes: coordination of a. sigma. bond to transition metals. Accounts of Chemical Research. 1988 Mar;21(3):120-8.

Park HL, Chung YC. Hydrogen storage in Al and Ti dispersed on graphene with boron substitution: First-principles calculations. Computational Materials Science. 2010 Oct 31;49(4): S297-301.

Beheshti E, Nojeh A, Servati P. A first-principles study of calcium-decorated, boron-doped graphene for high capacity hydrogen storage. Carbon. 2011 Apr 30;49(5):1561-7.

Tokarev A, Avdeenkov AV, Langmi H, Bessarabov DG. Modeling hydrogen storage in boron‐substituted graphene decorated with potassium metal atoms. International Journal of Energy Research. 2015 Mar 25;39(4):524-8.

Figure 1
(Invited) Fundamentals of Oxo-Functionalized Graphene and Graphene Oxide
Authors: Eigler Siegfried 
Published: February 2020

The structure of graphene oxide is a matter of discussion since the first description around 1860, long before the structure of graphite was known. The confusion about the chemical structure can now be analyzed in many aspects.
We introduced oxo-functional graphene as a novel class of materials, which bears in contrast to conventional graphene oxide a hexagonal carbon lattice, a high surface purity and therefore on-plane functional groups in majority, as demonstrated by HRTEM micrographs.[1] Moreover oxo-G bears no relevant amounts of oxidative debris and thus, graphene oxide is considered as a one-component system.[2]. Oxo-G can be used to control the chemistry of surface functional groups and we identified endoperoxides as source of the toxicity of oxo-G, relevant for bio-applications.[3] Controlling the on-plane reactions is the basis for controlled chemistry of graphene oxide and we demonstrate the extention of the life-time of perovskite/PCBM solar cells.[4]
It allows increasing the performance of rationally designed graphene derivatives in applications, such as information storage or solar cells.

REFERENCES

[1] B. Butz, C. Dolle, C. E. Halbig, E. Spiecker and S. Eigler, Angew. Chem. Int. Ed., 2016, 55, 15771-15774.
[2] A. Naumov, F. Grote, M. Overgaard, A. Roth, C. E. Halbig, K. Norgaard, D. M. Guldi and S. Eigler, J. Am. Chem. Soc., 2016, 138, 11445-11448.
[3] H. Pieper, S. Chercheja, S. Eigler, C. E. Halbig, M. R. Filipovic and A. Mokhir, Angew. Chem. Int. Ed., 2016, 55, 405-407.
[4] H. Chen, Y. Hou, C. E. Halbig, S. Chen, H. Zhang, N. Li, F. Guo, X. Tang, N. Gasparini, I. Levchuk, S. Kahmann, C. O. Ramirez Quiroz, A. Osvet, S. Eigler and C. J. Brabec, J. Mater. Chem. A, 2016, 4, 11604-11610.
(Invited) Chemistry of Novel 2D Materials: Black Phosphorus and Antimonene
Authors: Abellán Gonzalo 
Published: February 2020

Two-dimensional (2D) materials have attracted increasing interest in the last few years due to their unique morphology and properties and their use in a variety of applications, ranging from electronics to energy storage or catalysis, to name a few. Apart from various well-established 2D materials, such as graphene, h-BN, or MoS2, black phosphorus (BP) has received considerable attention over the last two years because its direct bandgap and his appealing properties for electronic and ultrafast optoelectronic applications. However, its lack of environmental stability severely limits its synthesis and processing.
We have recently demonstrated that high-quality, few-layer BP nanosheets, with controllable size and observable photoluminescence, can be produced in large quantities by liquid phase exfoliation under ambient conditions.1 Beyond this success, a more sophisticated chemical modification is highly desirable, like the molecular doping, that is an effective and flexible method towards modulating the electronic properties of 2D materials. Herein, we have developed a chemical route for the non-covalent functionalization of BP with different moieties, including electron-withdrawing organic molecules or tailor-made surfactants.2 Moreover we have extended these concepts towards a new 2D material: antimonene, creating stable suspensions in water and developing its non-covalent functionalization.3

1) D. Hanlon, C. Backes, E. Doherty, C. S. Cucinotta, N. C. Berner, C. Boland, K. Lee, A. Harvey, P. Lynch, Z. Gholamvand, S. F. Zhang, K. P. Wang, G. Moynihan, A. Pokle, Q. M. Ramasse, N. McEvoy, W. J. Blau, J. Wang, G. Abellan, F. Hauke, A. Hirsch, S. Sanvito, D. D. O’Regan, G. S. Duesberg, V. Nicolosi, J. N. Coleman, Nat. Commun. 2015, 6, 8563.
2) G. Abellán, V. Lloret, U. Mundloch, M. Marcia, C. Neiss, A. Görling, M. Varela, F. Hauke, A. Hirsch, Angew. Chem. In. Ed., 2016, 55 (47), 14557.
3) C. Gibaja, D. Rodriguez-San-Miguel, P. Ares, J. Gómez-Herrero, M. Varela, R. Gillen, J. Maultzsch, F. Hauke, A. Hirsch, G. Abellán, F. Zamora, Angew. Chem. In. Ed., 2016, 55 (46), 14345.
Graphene Nanoribbon Synthesis with a Fluorinated Molecular Precursor
Authors: Hayashi Hironobu , Yamaguchi Junichi , Jippo Hideyuki , Sato Shintaro , Yamada Hiroko 
Published: February 2020

The surface-assisted reaction is a key process for graphene nanoribbons (GNRs) synthesis. So far, anthracene based compounds, as represented by 10,10’-dibromo-9,9’-bianthracene, are most-used molecular precursors for GNRs synthesis. However, even the simple anthracene based precursor molecules exhibit a variety of reactivity because the on-surface synthesis includes hierarchical reactions such as dehalogenation, polymerization, and cyclodehydrogenation. Considering that the reactivity of the small precursor molecules determines the final structure of GNRs, the key to success for synthesizing tailored GNRs is the deep understanding the relationship between the reactivity of the molecules and the geometry on the catalytic metal surface.
Here, we investigated the reactivity of a fluorinated precursor molecule during the GNR formation. The fluorine atoms were introduced at 2,3,6,7-positions of an anthracene sandwiched by 9-bromoanthracenes in order that the effect of fluorine substitution at the edge positions of polyanthrylene and GNRs would be investigated. Scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) indicate the formation of the edge-fluorinated polyanthrylenes. Interestingly, the following cyclodehydrogenation yields GNRs, dissociating the carbon-fluorine bonds at the edge positions of polyanthrylenes. Namely, the strong C-F bond survived during the polymerization step, but the following cyclodehydrogenation cleaved the C-F bond. Theoretical calculation implies that the structure of the intermediate state during the cyclodehydrogenation played an important role in the fluorine dissociation. Thus, the lessons from the dissociation of the strong C-F bond, which is believed as one of the strongest bonding in the solution chemistry, would provide the synthetic access to the proper design of precursor molecules for edge-functionalized GNRs.
(Invited) Push-Pull P-Extended porphyrins As Sensitizer for Dye-Sensitized Solar Cells
Authors: Wang Hong , Jinadasa Raja Gabadage , Hu Yi , Thomas Michael , D'Souza Francis , Yellappa Shivaraj 
Published: February 2020

Significant progress has been made on dye-sensitized solar cells sensitized by push-pull porphyrins in recent years.1-3 Through installing push-pull groups at porphyrin meso-positions, exceptionally high power conversion efficiencies have been achieved.4, 5 In this presentation, we present the synthesis and characterization of a series of novel opp-dibenzoporphyrins, and their application as sensitizers for dye-sensitized solar cells. These porphyrin sensitizers are designed through installation of push (electron-donating) and pull (electron-withdrawing) groups at the porphyrin beta-positions. Significant push-pull effects were observed for these porphyrins. The effect of different conjugated spacers on the power conversion efficiency of these dyes was investigated. It was found that inclusion of ethynylphenyl bridge between the donating group and porphyrin core would segregate the frontier orbitals. Our data also show that conjugated bridges appear to play important roles in determining their power conversion efficiency. The electronic and optical properties of these pi-extended porphyrins were measured using UV-Vis spectroscopy, life-time and steady state fluorescence spectroscopy, and cyclic voltammetry. DFT calculations were also performed for these porphyrins.

Reference

1. T. Higashino and H. Imahori, Dalton Trans., 2015, 44, 448-463.
2. M. Urbani, M. Gratzel, M. K. Nazeeruddin and T. Torres, Chem. Rev., 2014, 114, 12330-12396.
3. L. L. Li and E. W. Diau, Chem. Soc. Rev., 2013, 42, 291-304.
4. A. Yella, H.-W. Lee, H. N. Tsao, C. Yi, A. K. Chandiran, M. K. Nazeeruddin, E. W.-G. Diau, C.-Y. Yeh, S. M. Zakeeruddin and M. Grätzel, Science, 2011, 334, 629-634.
5. S. Mathew, A. Yella, P. Gao, R. Humphry-Baker, B. F. Curchod, N. Ashari-Astani, I. Tavernelli, U. Rothlisberger, M. K. Nazeeruddin and M. Gratzel, Nat. Chem., 2014, 6, 242-247.

Figure 1
Temperature-Dependent Hydrothermal Preparation of MoS2/Graphene Hybrid Electrocatalyst
Authors: Guo Xiaoru , Hou Yang , Ren Ren , Chen Junhong 
Published: February 2020

Two-dimensional (2D) hybrid materials have been studied for use in photovoltaics, water splitting, sensors, batteries, and many other applications, which are prepared from popular 2D nanomaterials into heterojunctions or 3-dimensional (3D) frameworks. Benefiting from their unique 2D structures and tunable bandgaps, 2D hybrid materials can offer both a high surface area and a suitable work function. Molybdenum disulfide (MoS2)/graphene hybrid material has been proved as a high-performance and low-cost catalyst for energy applications, but its optimum preparation condition is yet to be determined.
This work focuses on the 3D structure of MoS2/graphene hybrid and primarily studies the crystallization condition and morphology change of MoS2 in MoS2/graphene hybrids by a temperature-varying hydrothermal method. Flower-like MoS2 nanoflakes have been successfully grown on graphene nanosheets by using the hydrothermal method at temperatures from 150 to 240 oC. The resulting hybrid material was characterized to understand its temperature-dependent crystallization process and its electrochemical performance in the dye-sensitized solar cell and the hydrogen evolution reaction. Through high-resolution scanning electron microscopy and high-resolution transmission electron microscopy, the 3D structures can be clearly observed and compared. X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy are taken to identify the crystallization differences among different samples and understand temperature effects. The highest electrocatalytic efficiency for both the DSSC and the HER was obtained by preparing the MoS2/graphene hybrid at 180 oC, which benefits from both high reactivity of MoS2 1T phase and high conductivity of the hybrid structure. This research leads to a better understanding of temperature dependence of MoS2 crystallization and gives directions for better catalytic material design.
Supramolecular Metal Arraying in Porphyrin/Phthalocyanine Conjugates for Catalytic Applications
Authors: Tanaka Kentaro , Yamada Yasuyuki , Mihara Nozomi 
Published: February 2020

Recently, we reported synthesis of porphyrin/phthalocyanine conjugates linked by fourfold rotaxane. In the conjugate, a porphyrin and a phthalocyanine formed a heterodimer in a cofacial fashion (Fig. 1a). [1] The conjugate is a promising platform for supramolecular catalysts based on dinuclear porphyrinoid complexes, because various metal ions to be a functional center are able to be arrayed in the conjugate regioselectively to afford homo- and hetero-dinuclear centers in the conjugate. [2,3] Moreover, these arrays were expanded to hetero-trinuclear arrays (Fig. 1b). [3-6]
In this paper, we will present regioselective metal arraying in the conjugate and the supramolecular catalytic functions (Fig. 2). One of the methods to prepare the hetero-dinuclear complexes was to use the difference of metalation rate between porphyrin and phthalocyanine. We found reaction conditions for porphyrin-selective Fe(II) or Ni(II) insertion and phthalocyanine-selective Mn(II) insertion. Subsequent metalation to another porphyrinoid in the conjugate gave a hetero-dinuclear complex. We used these multinuclear complexes in the conjugate as catalysts. The dinuclear iron complex exhibited good catalytic activity in electrochemical reduction of molecular oxygen to water. [7]
References:
1) Y. Yamada, M. Okamoto, K. Furukawa, T. Kato, and K. Tanaka., Angew. Chem. Int. Ed.,
51, 709 (2012,).
2) Y. Yamada, N. Mihara, and K. Tanaka., Dalton Trans.,
42, 15873 (2013).
3) N. Mihara, Y. Yamada, and K. Tanaka., submitted.
4) Y. Yamada, N. Mihara, S. Shibano, K. Sugimoto, and K. Tanaka., J. Am.Chem. Soc.,
135, 11505 (2013).
5) Y. Yamada, S. Akine, K. Sugimoto, and K. Tanaka, Chem. Euro. J., 22, 12371 (2016).
6) N. Mihara, Y. Yamada, S. Akine, K. Sugimoto, and K. Tanaka., submitted.
7) N. Mihara, Y. Yamada, and K. Tanaka., submitted.

Figure 1
(Invited) Materials Design By Atmospheric Pressure Plasmas for Solar Energy Harvesting
Authors: Mariotti Davide 
Published: February 2020

Atmospheric pressure plasmas (APP) have demonstrated exceptional versatility to synthesize and modify a very wide range of materials with varying morphologies, sizes and compositions [1-3]. These include semiconducting, oxide and metal nanoparticles, nanostructured films and ultra-small quantum confined nanostructures. APPs have key features which would make the corresponding processes highly desirable for large scale manufacturing.
In recent years we have therefore focused our efforts in developing ad-hoc APP processes with in mind two main objectives. On one side we have developed processes that could be integrated in the fabrication of application devices so that we could demonstrate direct applicability of APPs to relevant device fabrication steps. In particular we have developed APP-based strategies for solar cell device fabrication [4]. At the same time we have tried to work bottom-up, whereby our materials synthesis approach was dictated by desired materials functionalities.
Here we will exemplify our efforts with a range of semiconducting nanoparticles and metal oxides to include Cu-, Zn-, Ni-, Mo- and Co-oxides. We will show different synthesis mechanisms and how specific properties such as bandgap, quantum confinement and plasmon resonance can be tailored guided by our materials needs. We will then demonstrate the materials functionalities within photovoltaic devices.
[1] Journal of Physics D: Applied Physics 43 (2010) 415402
[2] Chemical Physics Letters 478 (2009) 224
[3] Applied Physics Letters 104 (2014) 163103
[4] Plasma Process. Polym.
13 (2016) 70