Synthesis Of Advanced Materials Research Articles

Plasma-Assisted Synthesis and Surface Modification of Electrode Materials for Renewable Energy.

Renewable energy technology has been considered as a "MUST" option to lower the use of fossil fuels for industry and daily life. Designing critical and sophisticated materials is of great importance in order to realize high-performance energy technology. Typically, efficient synthesis and soft surface modification of nanomaterials are important for energy technology. Therefore, there are increasing demands on the rational design of efficient electrocatalysts or electrode materials, which are the key for scalable and practical electrochemical energy devices. Nevertheless, the development of versatile and cheap strategies is one of the main challenges to achieve the aforementioned goals. Accordingly, plasma technology has recently appeared as an extremely promising alternative for the synthesis and surface modification of nanomaterials for electrochemical devices. Here, the recent progress on the development of nonthermal plasma technology is highlighted for the synthesis and surface modification of advanced electrode materials for renewable energy technology including electrocatalysts for fuel cells, water splitting, metal-air batteries, and electrode materials for batteries and supercapacitors, etc.

The Solid Flame Phenomenon: A Novel Perspective

In this paper, the authors overview previous publications and present novel results related to self‐sustained solid‐state reactions: the solid flame. Due to recent advances in the fabrication of nano‐structured reactive media, this phenomenon, which is first reported fifty years ago, has found a new perspective for a wide variety of exothermic systems. These fundamental findings permit novel routes for synthesis of advanced engineering materials with controlled microstructure, as well as for design of high‐energy density systems with tuned parameters for energy release.

A Tunable Molten-Salt Route for Scalable Synthesis of Ultrathin Amorphous Carbon Nanosheets as High-Performance Anode Materials for Lithium-Ion Batteries.

Amorphous carbon is regarded as a promising alternative to commercial graphite as the lithium-ion battery anode due to its capability to reversibly store more lithium ions. However, the structural disorder with a large number of defects can lead to low electrical conductivity of the amorphous carbon, thus limiting its application for high power output. Herein, ultrathin amorphous carbon nanosheets were prepared from petroleum asphalt through tuning the carbonization temperature in a molten-salt medium. The amorphous nanostructure with expanded carbon interlayer spacing can provide substantial active sites for lithium storage, while the two-dimensional (2D) morphology can facilitate fast electrical conductivity. As a result, the electrodes deliver a high reversible capacity, outstanding rate capability, and superior cycling performance (579 and 396 mAh g-1 at 2 and 5 A g-1 after 900 cycles). Furthermore, full cells consisting of the carbon anodes coupled with LiMn2O4 cathodes exhibit high specific capacity (608 mAh g-1 at 50 mA g-1) and impressive cycling stability with slow capacity loss (0.16% per cycle at 200 mA g-1). The present study not only paves the way for industrial-scale synthesis of advanced carbon materials for lithium-ion batteries but also deepens the fundamental understanding of the intrinsic mechanism of the molten-salt method.

A Bifunctional Highly Efficient FeNx /C Electrocatalyst.

Herein, a type of Fe, N-codoped carbon electrocatalyst (FeNx /C, Fe-N-BCNT#BP) containing bamboo carbon nanotubes and displaying bifunctional high catalytic efficiency for both oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO2RR) is reported. It shows high electrocatalytic activity and stability for both the ORR process with onset potential of 1.03 VRHE in alkaline and the CO2RR to CO with high faradic efficiency up to 90% and selectivity of about 100% at low overpotential of 0.49 V. For CO2RR to CO, it is revealed that Fe3 C is active but the activity of FeNx centers is lower than that of C-N-based centers, contrary with that observed for ORR. Due to its low cost and high electrocatalytic performance for these two reduction reactions, the obtained catalyst is very promising for extensive application in future. The revealed huge activity difference of the same types of active sites for different reactions can efficiently guide the synthesis of advanced materials with multifunction.

Carbon nitride template-directed fabrication of nitrogen-rich porous graphene-like carbon for high performance supercapacitors

Facile yet rationally designed strategy for advanced electrode material synthesis is pivotal for energy storage. Herein, we report an protocol for g-C3N4 template-directed in-situ fabricating nitrogen-rich porous graphene-like carbon sheets (NPGCs) by using plasma-enhanced chemical vapor deposition followed with high-temperature pyrolysis process, which totally avoids the postsynthetic template-removal. The resultant NPGCs integrate a range of intriguing features including highly conductive interconnected structure (693 S m−1), abundant mesoporous with ultrahigh pore volume (4.35 cm3 g−1), large specific surface area (1277 m2 g−1), high N doping (8.75 wt%), and good wettability. As supercapacitor electrode, the NPGCs exhibit a quite encouraging specific capacitance of 261 F g−1 at 1 A g−1, excellent rate capability (189 F g−1 even at 100 A g−1), and outstanding cycle performance (97% capacitance retention at 10 A g−1 after 20000 cycles), which outperforms most carbon-based materials reported to date. Moreover, the assembled supercapacitors deliver a high power density of 28.4 kW kg−1 with a energy density of 6.53 Wh kg−1 at 100 A g−1. Our work is expected to open up new avenues for developing efficient nitrogen-doped porous carbon materials in a facile and viable way.

Hydrothermal syntheses of tungsten doped TiO2 and TiO2/WO3 composite using metal oxide precursors for charge storage applications

Synthesis of advanced functional materials through scalable processing routes using greener approaches is essential for process and product sustainability. In this article, syntheses of nanoparticles of titanium dioxide (TiO2), tungsten trioxide (WO3), WO3-doped titanium dioxide (W-TiO2) and TiO2/WO3 composite at hydrothermal conditions using corresponding metal oxide precursors are described. Electrochemical charge storage capabilities of the above materials are measured using cyclic voltammetry, charge-discharge cycling and electrochemical impedance spectroscopy in aqueous KOH electrolyte. The TiO2 and the WO3 nanoparticle showed a specific charge (Q) of ∼12 and ∼36 mA h g−1 at a current density of 2 A g−1 in 6 M KOH, respectively. The Q of TiO2 increased upon W doping up to 25 mA h g−1 for 5 wt% W-TiO2 and the WO3/TiO2 composite showed the highest storage capability (Q ∼40 mA h g−1). Changes in the charge storage capabilities of the doped and composite materials have been correlated to materials properties.

Theoretical investigation of structural, mechanical, elastic and vibrational properties of advanced materials under extreme conditions

One of the recent trends in materials science and technology is the research of the behavior of the materials under the extreme conditions both on the theoretical and experimental basis. There are limitations of the experimental methods, however, theoretical approach can be used as a supplement to the experimental results. As a consequence, in the last two decades a vast number of structure prediction calculations have been performed on chemical systems, focusing on the high-pressure and high temperature phases. In this work, we would like to present several computational studies and their connection to the actual synthesis routes: lead sulfide (PbS), barium sulfide (BaS), and aluminum nitride (AlN). The investigated compounds were calculated on ab initio level using the most advanced tools in quantum chemistry and computational material science including Hartree-Fock Theory, Density Functional Theory (DFT) and Hybrid (B3LYP) Approximation. Their structural, mechanical, elastic and vibrational properties have been investigated and in addition, we show structure candidates as the function of size, pressure and temperature and not previously observed in any of the investigated materials thus creating new possibilities for synthesis of advanced materials with improved physical, chemical, and/or mechanical properties.

Microwave-assisted synthesis of nanocrystalline binary and ternary metal oxides

ABSTRACTInterplay of chemistry and nanotechnology has effectively substantiated the ever-expanding horizons of materials chemistry, leading to a paradigm shift in (nano)materials synthesis. Current challenges of chemically processed materials include efforts to redesign synthetic procedures by using less hazardous starting materials, choosing milder reaction conditions, shortening time scale of chemical transformations and most importantly reduction of energy requirements. In this context, successful substitution of classical energy input by microwave radiation is a promising alternative in most fields of common chemical synthesis. This review highlights the latest developments in the synthesis of advanced inorganic materials by microwave-assisted chemical reactions. When compared to conventional convective and conductive heating techniques, microwave irradiation provides efficient internal volumetric heating through generation of localised high temperature zones in the reaction media by direct coupling of microwave energy to the molecules present in the reaction mixture, thereby enabling rapid synthesis with superior yield and both reduced reaction time as well as processing steps.Abbreviations: [BMIM]BF4: 1-butyl-3-methylimidazolium tetrafluoroborate; [C2mim][NTf2]: 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; [C4mim][NTf2]: 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide; [C12Py][ClO4]: N-dodecylpyridinium perchlorate; [OMIM]TA: 1-octyl-3-methylimidazolium trifluoroacetate; AAO: anodic aluminium oxide; acac: acetylacetone; CNCs: colloidal nanocrystal clusters; CTAB: cetrimonium bromide; DEG: diethylene glycol; EDA: ethylenediamine; EG: ethylene glycol; EGMM: 2-methoxyethanol; FESEM: field emission scanning electron microscopy; FTO: fluorine-doped tin oxide; h: hours; HMT: hexamethylenetetramine; HR-TEM: high-resolution transmission electron microscopy; HPC: hydroxypropyl cellulose; IL: ionic liquids; ITO: indium tin oxide; MEA: ethanolamine; min: minutes; MPA: 3-mercaptopropionic acid; MW: microwave; nm: nanometre; NMP: n-methyl-2-pyrrolidon; OP: p-octyl polyethylene glycol phenylether; P(VP-NVP-St): polyvinylpyrrolidone-polyvinylpyrrolidone-polystyrene; P-103: polyethyleneoxide–polypropyleneoxide–polyethyleneoxide copolymer; PAA: polyacrylic acid; PC: polycarbonate; PEG: polyethylene glycol; PEG-PPO-PEG: poly(ethylene glycol-poly(p-phenyleneoxide)-poly(ethylene glycol); PET: polyethylene terephthalate; Pluronic P123: triblock copolymer; poly(ethyleneglycol)-block-poly(propyleneglycol)-block-poly(ethylene glycol); Pluronic F127: poloxamer; PPO: poly(p-phenyleneoxide); PS(540)-b-PEO(220): polystyrene-block-poly(ethyleneoxide) diblock copolymer with 540 monomerunits of styrene and 220 monomer units of ethylene oxide; PVA: polyvinyl alcohol; PVP: polyvinylpyrrolidone; QDs: quantum dots; R: ratio; s: seconds; SBA-15: Santa Barbara Amorphous-15 (mesostructured silica); SDBS: sodium dodecylbenzenesulfonate; SDS: sodium dodecyl sulphate; tan δ: dielectric loss factor; TBAH: tetrabutylammonium hydroxide; TEAB: tetraethylammonium bromide; TEG: triethylene glycol; TEM: transmission electron microscopy; TMAH: tetramethylammonium hydroxide; TMP: 2,2,6,6-tetramethylpiperidine; TOPO: trioctyl phosphine oxide; TTIP: titanium isopropoxide

Novel Hydrogel-Advanced Modified Clay Nanocomposites as Possible Vehicles for Drug Delivery and Controlled Release.

Present study refers to the synthesis of new advanced materials based on poly(methacrylic acid) (PMAA) with previously reported own advanced modified clays by edge covalent bonding. This will create the premises to obtain nanocomposite hydrogels with combined hydrophilic-hydrophobic behavior absolutely necessary for co-delivery of polar/nonpolar substances. For the synthesis, N,N’-methylenebisacrylamide was used as cross-linker and ammonium persulphate as initiator. As a consequence of the inclusion of clay into the polymer matrix and the intercalation of PMAA between the layers as well as the presence of hydrophobic interactions occurred between partners, the final hydrogel nanocomposites possessed greater swelling degrees, slower de-swelling process and enhanced mechanical properties depending on the clay type in comparison with pure hydrogel. In vitro MTS ([3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt]) colorimetric assay showed that direct exposure with PMMA-clay-based constructs did not affect cell viability and proliferation in time (24 and 48 h) on either normal or adenocarcinoma cell lines.

A proposition of peritectic structures as candidates for thermal energy storage

Peritectic structures are proposed as candidates for thermal energy storage in solar power plants. According to the evolution of Concentrated Solar Plants (CSP) technologies, the development of a new technology for ultra-compact Thermal Energy Storage (TES) over an extended range of temperatures is required. Identification, synthesis, analysis and characterization of innovative advanced materials should allow reaching outstanding energy density, long term stability, reasonable investment and could also enhancing heat transfers. All these assets make the ‘peritectics’ very appealing potential candidates for heat storage. In this work, a theoretical study based on phase diagrams modeling is performed to investigate the possible use of binary peritectic structures. It has been shown that peritectics can provide significantly increased energy density compared to simple melting/solidification processes, mainly because they involve chemical reactions. These materials could hence represent a very innovative and promising route for ultra-compact heat storage over a wide range of temperatures [300 - 700°C].

Extraction of Meso-pores Amorphous SiO2 from Van Pumice

Background: Amorphous silica is widely used in cement and ceramic industry and also for the synthesis of many advanced materials. Method: Generally, it is produced using sol-gel and precipitation method. In the present study, amorphous SiO2 was extracted from acidic pumice collected from Van Basin in Turkey by alkaline treatment method. Result: The identification and chemical compositions of the acidic pumice and the amorphous SiO2 were determined by XRD, FTIR, XRF and BET. Conclusion: The results showed that highly pure amorphous silica powder having a remarkable surface area (358 m2/g) with meso-pore structure was successfully extracted from the acidic pumice samples. Keywords: Amorphous SiO2, Pumice, meso-pore, alkaline treatment, Van Pumice, silica gel.

The initial stages of multicomponent particle formation during the gas phase combustion synthesis of mixed SiO2/TiO2

ABSTRACTThe ability to properly scale the synthesis of advanced materials through combustion synthesis routes is limited by our lack of knowledge regarding the initial stages of particle formation. In flame aerosol reactors, the high temperatures, fast reaction rates, and flame chemistry can all play a critical role in determining the properties of the resulting nanomaterials. In particular, multicomponent systems pose a unique challenge as most studies rely on empirical approaches toward designing advanced composite materials. The lack of predictive capabilities can be attributed to a lack of data on particle inception and growth below 2 nm. Measurements for the initial stages of particle formation during the combustion synthesis of SiO2 and composite SiO2/TiO2 using an atmospheric pressure inlet time-of-flight mass spectrometer are presented. Both positively and negatively charged clusters can be measured and results show the presence of silicic acid species which grow through dehydration, hydrogen abst...

Selective ortho C-H Activation of Pyridines Directed by Lewis Acidic Boron of PBP Pincer Iridium Complexes.

Transition-metal mediated C-H functionalization has emerged as a powerful method in the chemistry relevant to the synthesis of pharmaceuticals, agrochemicals, and advanced materials. Because organic molecules typically contain multiple types of C-H bonds, selective C-H functionalization is a major ongoing challenge. C-H activation of heteroatom-containing organics has often been approached via the use of the directing effect, whereby the coordination to the basic heteroatom directs the reactive metal center to a specific C-H bond. We now report a different approach where the nitrogen donor in pyridine derivatives coordinates to an ancillary Lewis acidic boryl ligand directly attached to the metal (iridium) center, as opposed to the metal itself. This topology directs the iridium center to activate a different C-H bond than in the cases of directing donor coordination to the metal. Using this strategy, we demonstrate ortho-regiospecific C-H activation of pyridines and an example of the subsequent functionalization via C-C bond formation.

New Insights into Effects of Aromatic Amino Acids on Hydroxyapatite

Biomimetics inspired by superstructures and extraordinary properties of teeth have resulted in tooth repair and the generation of novel materials. However, little attention has been paid to tooth color, whose origin remains unknown. Based on recent studies, fluorophores—mainly aromatic amino acids (AAAs) in proteins—might be responsible for tooth color. We synthesized carbonated hydroxyapatite (HA; the mineral phase of teeth) in the presence of different amino acids (AAs; the basic units of protein matrix of teeth) as a simplified model of teeth to explore the color source at the AA level. After measuring the fluorescence and color characteristics of HA-AAs before and after bleaching treatment, we found that only HA, synthesized in the presence of AAAs, exhibited remarkable fluorescence and color property. Furthermore, linearly increased fluorescence intensity and deeper color were observed with an increase in AAA content in HA-AAAs. Similarly, significantly decreased absorbance of HA-AAAs between 250 and 300 nm in ultraviolet spectra, declined fluorescence intensity, and decolored performance of HA-AAAs were observed after bleaching treatment. The results showed that AAAs contributed to the fluorescence and color properties of HA and that hydrogen peroxide might whiten HA-AAAs by oxidizing the benzene ring in AAAs. These findings are of great significance in promoting the synthesis of advanced tooth-colored materials and furthering our understanding of the possible mechanisms of hydrogen peroxide. Moreover, our study shed light on the importance of AAAs and might provide new ideas for investigations of biomineralization and biomimetics.

New approach to the preparation of grafted ion exchange membranes based on UV-oxidized polymer films and sulfonated polystyrene

The new way for the synthesis of advanced functional materials for water purification and alternative energy, namely, grafted cation-exchange membranes based on UVoxidized aliphatic polymers (polypropylene and polymethylpentene) and sulfonated polystyrene, is proposed.

Fabricating 3D hierarchical porous TiO2 and SiO2 with high specific surface area by using nanofibril-interconnected cellulose aerogel as a new biotemplate

3D porous inorganic materials play a vital role in various applications, such as adsorption, catalysis, and electrochemistry, and are an ongoing interest in the synthesis of advanced porous materials. Herein, we aimed to fabricate 3D free-standing hierarchical porous TiO2 and SiO2 with tunable porous structure and high specific surface area by using cellulose aerogel as a new biotemplate. The results revealed that the hierarchical porous structure of 3D porous TiO2 and SiO2 could be easily tailored by controlling annealing process. The physicochemical structure of the resultant porous materials, such as morphology, specific surface area and phase structure, strongly depended on the thermal stability of the biotemplate. 3D porous TiO2 and SiO2 with specific surface areas of high up to 221.1m2/g and 451.3m2/g could be obtained, respectively. In addition, the as-prepared TiO2 exhibited a high photocatalytic activity, demonstrating their potential application in advanced photocatalysis.

Controllable Microfluidic Fabrication of Microstructured Materials from Nonspherical Particles to Helices.

This work reports on a facile and flexible strategy based on the deformation of encapsulated droplets in fiber-like polymeric matrices for template synthesis of controllable microstructured materials from nonspherical microparticles to complex 3D helices. Monodisperse droplets generated from microfluidics are encapsulated into crosslinked polymeric networks via an interfacial crosslinking reaction in microchannel to in situ produce the droplet-containing, fiber-like matrices. By stretching and twining the dried fiber-like matrices, the encapsulated droplets can be flexibly engineered into versatile shapes for template synthesis of controllable nonspherical microparticles and helices. Moreover, magnetic helices can be fabricated by simply dispersing magnetic Fe3 O4 nanoparticles in the droplets to achieve rotational and translational motion under a rotated magnetic field. This work provides a simple and versatile strategy for the template synthesis of advanced functional microstructured materials with flexible shapes.

Self-supported hierarchical MnCo2O4@Ni3S2 core–shell heterostructures on Ni foam as a binder-free electrode for high-performance supercapacitors

Abstract Despite considerable efforts have been devoted to the design and synthesis of advanced electrode materials for supercapacitors (SCs), it is still a huge challenge to achieve high-performance electrode materials with the large practical capacity and high rate capability. Herein, novel self-supported MnCo 2 O 4 @Ni 3 S 2 core–shell heterostructures (CSHs) as a binder-free electrode are rationally designed and constructed by homogeneously growing Ni 3 S 2 nanosheets onto the hexagonal prism-like MnCo 2 O 4 microstructures on Ni foam (NF). Impressively, compared with the pristine MnCo 2 O 4 and Ni 3 S 2 electrodes, the prepared MnCo 2 O 4 @Ni 3 S 2 CSHs electrode demonstrates a remarkably enhanced specific capacitance (2807 F g −1 at 3 A g −1 ) along with a significantly improved rate capability (69% capacitance retention at 30 A g −1 ). These findings not only suggest the promising application of self-supported MnCo 2 O 4 @Ni 3 S 2 CSHs as advanced SCs electrode materials but also provide an alternative way for constructing next-generation high-performance SCs with remarkably improved electrochemical performance.

Polyazulene based materials for heavy metal ions detection

Azulene is a special monomer used to functionalize electrodes, due to its spontaneous electron drift from the seven-membered ring to the five-membered ring. The seven-membered ring of the molecule may act as electron acceptor, while the five-membered ring – as electron donor. This leads to very attractive properties for the synthesis of functional advanced materials like: materials with nonlinear optical and photorefractive properties, cathode materials for lithium batteries, or light emitting diodes based on organic materials. Azulene derivatives have been used rarely to the metal ions electroanalysis. Our study concerns the synthesis and electrochemical characterization of a new azulene based monomer 4-(azulen-1-yl)-2,6-bis((E)-2-(thiophen-3-yl)vinyl)pyridine (L). L has been used to obtain modified electrodes by electrochemical polymerization. PolyL films modified electrodes have been characterized by cyclic voltammetry in ferrocene solutions. The complexing properties of polyL based functional materials have been investigated towards heavy metals (Pb, Cd Hg, Cu) by preconcentration – anodic stripping technique in order to analyze the content of these cations from water samples.

Thermally Stable Metal-Organic Framework-Templated Synthesis of Hierarchically Porous Metal Sulfides: Enhanced Photocatalytic Hydrogen Production.

Porous nanostructured materials are demonstrated to be very promising in catalysis due to their well accessible active sites. Thermally stable metal-organic frameworks (MOFs) as hard templates are successfully utilized to afford porous metal oxides and subsequently metal sulfides by a nanocasting method. The resultant metal oxides/sulfides show considerable Brunauer-Emmett-Teller (BET) surface areas, by partially inheriting the pore character of MOF templates. Preliminary investigation on the obtained hierarchically porous CdS for water splitting, as a proof of concept, demonstrates its much higher activity than both corresponding bulk and nanosized counterparts, under visible light irradiation. Given the structural diversity and tailorability of MOFs, such synthetic approach may open an avenue to the synthesis of advanced porous materials for functional applications.