Chemical Solution Route Research Articles

Low Cost, Fast Solution Synthesis of 3D Framework ZnO Nanosponges.

An efficient, template-free solution-chemical route to nanostructured ZnO sponges is presented: A mixture of Zn(NO3)2·6H2O, Zn(OAc)2·2H2O, and triethanolamine in methanol was evaporated to a highly viscous liquid and rapidly heated to >200 °C for 1-3 min to achieve highly porous, nanocrystalline sponges of ZnO. The viscous precursor concentrate obtained on evaporation in air was characterized by TG, DSC, and IR spectroscopy, and the product ZnO sponges by XRD, SEM, TEM, and IR spectroscopy. The fast reaction forming ZnO started at 140 °C and finished within a few seconds. Scherrer analysis of the XRD peak broadening showed average crystallite sizes of 8 to 11 nm for ZnO prepared by annealing at 200-450 °C (3 min), while grain growth to 134 nm was observed from 500 to 900 °C (3 min). The ZnO powders obtained at 200-900 °C had cell dimensions of a = 3.25 Å and b = 5.21 Å, matching the ZnO literature data well. SEM and TEM analyses showed highly porous, bread-like 3D nanostructures built by ca. 30-70 nm thick walls of ZnO crystallites of the approximate average sizes given by the XRD Scherrer analysis. It seems that the crystal growth above 450 °C takes place within the ZnO 3D structure obtained at lower temperatures without much sintering of the larger porous structure.

Light-Assisted Synthesis of Hierarchical Flower-Like MnO2 Nanocomposites with Solar Light Induced Enhanced Photocatalytic Activity

We have demonstrated a novel solution chemistry route for the synthesis of nanoscale hierarchical flower-like MnO2 through a light-assisted decomposition of a manganese precursor over the surface of a clay nanotube. By tuning the reaction conditions, we have successfully synthesized δ-MnO2 flowery nanostructures comprising assemblies of intersected nanosheets and subsequently studied their photocatalytic activity for the degradation of organic dyes under natural sunlight irradiations. The crystallographic phase dependent photocatalytic activity of MnO2 nanocomposites has also been carried out toward the photodegradation of dyes, indicating δ-MnO2 nanostructures possess higher catalytic efficiency compared to α-MnO2. The underlying mechanism demonstrates the formation of reactive oxygen species, which in turn facilitate the degradation of dyes and also substantiates that there is no need of any supplementary oxygen sources during photodegradation. The outstanding performance of the hierarchical δ-MnO2 nano...

Topography evolution of rough-surface metallic substrates by solution deposition planarization method

As an emerging technique for surface smoothing, solution deposition planarization (SDP) has recently drawn more attention on the fabrication of the second generation high temperature superconducting (2G-HTS) tapes. In our work, a number of amorphous oxide layers were deposited on electro-polished or mirror-rolled metallic substrates by chemical solution route. Topography evolution of surface defects on these two types of metallic substrates was thoroughly investigated by atomic force microscopy (AFM). It was showed that root mean square roughness values (at 50×50μm2 scanning scale) on both rough substrates reduced to ∼5nm after coating with SDP-layer. The smoothing effect was mainly attributed to decrease of the depth at grain boundary grooving on the electro-polished metallic substrate. On the mirror-rolled metallic substrates, the amplitude and frequency of the height fluctuation perpendicular to the rolling direction were gradually reduced as depositing more numbers of SDP-layer. A high Jc value of 4.17MAcm−2 (at 77K, s.f.) was achieved on a full stack of YBCO/CeO2/IBAD-MgO/SDP-layer/C276 sample. This study enhanced understanding of the topography evolution on the surface defects covered by the SDP-layer, and demonstrated a low-cost route for fabricating IBAD-MgO based YBCO templates with a simplified architecture.

Protonation of Graphitic Carbon Nitride (g-C3N4) for an Electrostatically Self-Assembling Carbon@g-C3N4 Core–Shell Nanostructure toward High Hydrogen Evolution

The development of new, appealing metal-free photocatalysts is of great significance for photocatalytic hydrogen evolution. Herein, an electrostatic self-assembly method to form a unique core–shell architecture of a colloid of carbon spheres with graphitic carbon nitride (g-C3N4) has been developed by a one-step chemical solution route. The chemical protonation of g-C3N4 solids with strong oxidizing acids (such as HNO3) is an efficient pathway toward the sol procedure of stable carbon nitride colloids, which can cover the surface of carbon spheres via electrostatic adsorption. On account of the unique polymeric matrix of g-C3N4 and reversible hydrogen bonding, the carbon@g-C3N4 derived from the sol solution showed high mechanical stability with broadened light absorption and enhanced conductivity for charge transport. Thus, the carbon@g-C3N4 core–shell structure exhibited remarkably enhanced photoelectrochemical performance. This polymer system is envisaged to hybridize with desirable functionalities (suc...

Fabrication of dense CIGS film by mixing two types of nanoparticles for solar cell application

Solution method fabrication of copper indium gallium selenide (CIGS) solar cells has attracted researchers due to easy fabrication and cost effective potential. Despite the encouraging results, the process of fabrication of solution processed solar cell faces challenges like use of toxic chemicals, high temperature processing to achieve large grain and dense CIGS absorber film for highly efficient device. Even though many methods have been developed, the voids generated in the CIGS absorber film after high temperature processing adversely affect the performance of fabricated CIGS solar cell to reach its maximum efficiency up to 20% which has already been achieved for vacuum deposited CIGS absorber film. A dense CIGS absorber film can be deposited by tailoring the size of nanoparticles in the ink solution. In this work, two types of nanoparticles, one having 200–500 nm size nanopowder prepared by ball-milling and other with 20–30 nm nanoparticles prepared using chemical solution route are mixed to prepare ink solution and deposited on the substrate to achieve dense and voids free absorber CIGS film . The smaller CIGS nanoparticles were found to occupy voids generated among the bigger CIGS nanopowder under low temperature sintering process. The performance of fabricated solar cells was found to improve when the concentration of smaller nanoparticles increases in the mixture. Solar cell fabricated with CIGS absorber layer deposited using mixture of nanoparticles exhibited 2.1% efficiency whereas only bigger nanopowder absorber film hardly exhibited any photovoltaic response under sintering at 250°C in ambient atmosphere.

Facile synthesis of tungsten trioxide 3D architectures by a simple chemical solution route and photodegradation of Rhodamine B: structural, thermal, optical and impedance studies

A facile chemical precipitation method for slab and flower like WO3 microstructure having three-dimensional (3D) architecture is reported. The as-prepared WO3 powder specimens were characterized by X-ray diffraction (XRD) combined with Rietveld refinements, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and UV–vis spectroscopy. SEM and XRD results revealed that the hierarchical WO3 microstructures with uniform flower-like morphology are congregated by number of interleaving nanosheets which have thickness of 150–180 nm and are crystallized in a single monoclinic WO3 phase. Thermo-gravimetric analysis shows a major weight loss of 8% due to evaporation of adsorbed water. The impedance spectroscopy of compact WO3 pellets showed that all samples were semiconducting with a minute difference in electrical properties. The photo-catalytic activity of the as-prepared WO3 samples was evaluated by the degradation of Rhodamine B (RhB) under ultra-violet light irradiation. The results showed that 3D hierarchical architectures exhibits high photo-catalytic efficiency compared with the slab like structure due to their porous hierarchical structures. The optical band gap energy of slab like structure is found to be lowered compared to flower-like WO3 structures. These tunable optical and transport features allow the development of new materials for potential applications as photo-catalysts, transparent conducting electrodes, electrochromic and sensor devices.

Flexible transparent displays based on core/shell upconversion nanophosphor-incorporated polymer waveguides

Core/shell (C/S)-structured upconversion nanophosphor (UCNP)-incorporated polymer waveguide-based flexible transparent displays are demonstrated. Bright green- and blue-emitting Li(Gd,Y)F4:Yb,Er and Li(Gd,Y)F4:Yb,Tm UCNPs are synthesized via solution chemical route. Their upconversion luminescence (UCL) intensities are enhanced by the formation of C/S structure with LiYF4 shell. The Li(Gd,Y)F4:Yb,Er/LiYF4 and Li(Gd,Y)F4:Yb,Tm/LiYF4 C/S UCNPs exhibit 3.3 and 2.0 times higher UCL intensities than core counterparts, respectively. In addition, NaGdF4:Yb,Tm/NaGdF4:Eu C/S UCNPs are synthesized and they show red emission via energy transfer and migration of Yb3+ → Tm3+ → Gd3+ → Eu3+. The C/S UCNPs are incorporated into bisphenol A ethoxylate diacrylate which is used as a core material of polymer waveguides. The fabricated stripe-type polymer waveguides are highly flexible and transparent (transmittance > 90% in spectral range of 443–900 nm). The polymer waveguides exhibit bright blue, green, and red luminescence, depending on the incorporated UCNPs into the polymer core, under coupling with a near infrared (NIR) laser. Moreover, patterned polymer waveguide-based display devices are fabricated by reactive ion etching process and they realize bright blue-, green-, and red-colored characters under coupling with an NIR laser.

Polypyrrole layer coated MnOx/Fe2O3 nanotubes with enhanced electrochemical performance for lithium ion batteries

MnOx/Fe2O3/polypyrrole nanotubes have been fabricated by a facile method, which involves a hydrothermal method, chemical solution route, annealing process and a subsequent chemical polymerization method. Electrochemical measurement shows that MnOx/Fe2O3/polypyrrole nanotubes display excellent electrochemical properties. A reversible specific capacity of 1060mAhg−1 is achieved after 100 cycles at the current density of 200mAg−1. Even at higher current density of 5000mAg−1, the specific capacity of the electrode can be kept at 630mAhg−1. The excellent electrochemical performances are ascribed to the synergetic effect of different components and the conductive polypyrrole layer.

Synthesis of Cu2SnS3 nanosheets as an anode material for sodium ion batteries

Single crystalline Cu2SnS3 nanosheets with exposed (220) planes have been synthesized via a facial solvothermal solution chemical route. The solvent of ethylenediamine hindered the growth along the [110] direction and facilitated the formation of two dimensional nanostructures. Electrochemical performance of Cu2SnS3 electrodes in sodium ion batteries was investigated. Cu2SnS3 electrodes exhibit an initial sodiation capacity of 586 mAh/g and 178 mAh/g after 50 cycles. The electrochemical properties of Cu2SnS3 nanosheets suggest it is a potential anode material for sodium ion batteries.

Formulation of Mechanochemically Evolved Fly Ash Based Hybrid Inorganic–Organic Geopolymers with Multilevel Characterization

In this research, advanced hybrid inorganic–organic geopolymeric material is developed by environmentally and user friendlier approach. The presented novel approach for geopolymer formation certainly overcomes the existing drawbacks of geopolymerization technology. The effect of rice husk ash and Na2O/SiO2 ratios on geopolymer gel formation and mechanical strength has been previously identified via solution chemistry route; however, development of geopolymeric material having hybrid inorganic–organic characters via together mechanochemical grinding of raw materials and effect of mechanochemically activated Na2SiO3 on geopolymeric properties via solid state route has never before been explored. Together mechanochemical grinding of raw materials of varying compositions in solid state resulted in the formation of ready to use geopolymeric precursors; which on just addition of water led to development of advanced hybrid inorganic–organic geopolymeric material with considerably enhanced properties. XRD, FTIR and SEM characterization data of developed geopolymeric precursor powder and hybrid inorganic–organic geopolymeric material are reported and discussed in detail. As the results of the investigations, the relationship between geopolymer composition, grinding mechanism and material properties established. The composition which exhibited synergistic effect of both rice husk and SMS is found to be excellent in performance. The study showed that it is practical and better to adopt this greener solid state approach for preparation of geopolymer instead of user-unfriendlier hazardous alkaline solution based approach, to achieve sustainable growth in geopolymers as like Portland cement.

Effect of zinc doping on phase evolution and characterization of nanocrystalline bismuth ferrite synthesized by chemical solution route

Bismuth ferrite a multiferroic material at room temperature is synthesized by solution route. BiFe1-xZnxO3 with (x = 0.05, 0.075, 0.1, 0.125) has been prepared by doping bismuth ferrite with zinc at Fe site. Annealing of all the samples is carried at 450 °C for 2 h. The phases are identified by X-ray diffraction (XRD), and it is observed that all the samples are rhombohedral for undoped and 5, 7.5, 10, 12.5% zinc doped bismuth ferrite crystallites along with major planes of orientation. Using Scherrer’s formula, it is confirmed that prepared undoped and zinc doped bismuth ferrites are nanocrystallites in dimension. Field emission scanning electron microscopy (FESEM) showed the structural morphology of the prepared nanocrystallites and seems to be agglomerated in form with anisotropic growth and interconnected pores. Energy dispersive X-ray spectroscopy (EDX) studies confirmed the presence of required elements for the successful synthesis in preparing undoped and zinc doped bismuth ferrite samples. The molecular signature of the samples is determined by Fourier transform infrared spectroscopy (FTIR) for both undoped and zinc doped bismuth ferrite. Doping leads to optimize changes in dielectric properties, comparable change in ampere as obtained from I-V curve. I-V curve obtained is nonlinear, while magnetic property improves, since Zn doping modifies spiral spin magnetic moment due to its particle size near to wavelength of antiferromagnetic axis of rotation and suppression of cycloid spin structure.

ChemInform Abstract: Fabrication, Characterization and Applications of Iron Selenide

AbstractReview: 100 refs.

Synthesis of the porous NiO/SnO2 microspheres and microcubes and their enhanced formaldehyde gas sensing performance

Porous NiO/SnO2 microspheres and microcubes were obtained using a facile chemical solution route combined with a subsequent calcination process. The morphologies and crystal structures of the products were comprehensively characterized via X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer–Emmett–Teller N2 adsorption-desorption analyses. The process of inducing porosity began with the NiSn(OH)6 precursors formed by the co-precipitation of the metal ions from the aqueous solution. Thermal decomposition of the precursors led to an intimate mixture of cubic phase NiO and tetragonal phase SnO2 and formed the porous NiO/SnO2 microspheres and microcubes. The gas-sensing properties of the as-prepared porous NiO/SnO2 microspheres and microcubes for toxic volatile organic compounds (VOCs), such as formaldehyde, ethanol, benzene, methanol, acetone, and toluene, were investigated. Compared with other VOCs gases, the porous NiO/SnO2 microsphere and microcube sensors exhibited a high response to formaldehyde. As for the porous NiO/SnO2 microsphere sensor, the detection limit of formaldehyde was approximately 0.13ppm (signal-to-noise ratio, S/N=3). The relationship between the gas-sensing performance and the microstructure of the porous NiO/SnO2 micro/nanomaterials was also discussed.

Controlled synthesis of porous Ni-doped SnO2 microstructures and their enhanced gas sensing properties

Porous Ni-doped SnO2 microspheres and microcubes were obtained via a facile chemical solution route followed by calcination and acid-washing process. Their structural and morphological evolution was characterized using a range of techniques. The process of inducing porosity began with crystalline single-phase NiSn(OH)6 precursors formed by the co-precipitation of metal ions from an aqueous solution. Thermal decomposition of the precursors led to an intimate mixture of cubic phase NiO and tetragonal phase SnO2. The Ni-doped SnO2 microspheres and microcubes were obtained after a simple acid-washing process. A decomposition–aggregation–dissolution process was proposed to explain the formation of these structures. The gas-sensing properties of the as-prepared porous Ni-doped SnO2 microspheres and microcubes for toxic volatile organic compounds, such as formaldehyde, ethanol, benzene, methanol, acetone, and toluene, were investigated. The enhanced sensing performance of the porous Ni-doped SnO2 microspheres was demonstrated. The detection limits of formaldehyde and ethanol were approximately 0.17 and 0.09 ppm (signal-to-noise ratio, S/N = 3), respectively. The enhanced sensing performance of the porous Ni-doped SnO2 microspheres was attributed to their Ni-dopant, unique porous structure and large surface area.

Fabrication, characterization and applications of iron selenide

This review article presents fabrication of FeSe by solid state reactions, solution chemistry routes, chemical vapor deposition, spray pyrolysis and chemical vapor transport. Different properties and applications such as crystal structure and phase transition, band structure, spectroscopy, superconductivity, photocatalytic activity, electrochemical sensing, and fuel cell activity of FeSe have been discussed.

Effect of solvent on the synthesis of AgBiSe2 nanostructures

A facile solution chemical route has been developed for synthesis of AgBiSe2 nanostructures in a controllable manner via employing porous anodic aluminum oxide (PAA) as a template. Single-crystalline AgBiSe2 nanowires or nanocrystals with even size can be controlled synthesized by changing the solvent in the reaction. Nanowires growth direction is perpendicular to the (104) planes. The variation of the morphology of AgBiSe2 from nanowires to uniform nanoparticles may be due to the effect of solvent on the nanocrystals nucleation and growth.

Ni3Se2 nanoforest/Ni foam as a hydrophilic, metallic, and self-supported bifunctional electrocatalyst for both H2 and O2 generations

Ni3Se2 nanoforest has been successfully grown on Ni foam via a facile one-step and cost-effective solution-chemical route. This handy strategy endues the product with three characteristics: metallic Ni3Se2, hydrophilic and aerophobic surface, as well as self-support on highly conductive substrate. The as-synthesized Ni3Se2 nanoforest/Ni foam shows excellent electrocatalytic activity and stability for both HER and OER.

Synthesis and Consolidation of Nano-Sized Cu Coated SiC Powders by a Chemical Method and Spark Plasma Sintering

Cu-70 vol% SIC composites with dense microstructure and sound interface between Cu and SIC grains were fabricated by solution chemistry route and spark plasma sintering. Two methods for developing powder mixtures of Cu and uncoated or pre-coated SIC were compared on the basis of the resulting microstructures. The pre-coating of Si(Al)OC onto SiC powders was prepared by curing and pyrolysis of Al-modified polycarbosilane. SiC/Cu composites were obtained by hydrogen reduction and densified using spark plasma sintering of pre-coated SIC and Cu-nitrate powder mixtures. The powder mixture showed a homogenous dispersion of nano-sized Cu particles on the surface of SIC powers. Microstructural observation revealed that the sintered composite using powder mixture with pre-coating of Al-PCS onto SiC powders showed dense microstructure and good contact between Cu and SIC grains due to the improved wettability by barrier coating. The results suggested that the SiC/Cu composite with required microstructural characteristics can be fabricated by using Al-PCS coated SIC powder mixture, more effectively.

Assembling tin dioxide nanorods on carbon nanotubes by a chemical solution method

ABSTRACTNanocomposites have significant potential in development of advanced materials and nanotechnology applications. Here, multi-walled carbon nanotubes (MWCNTs) sheathed with tin dioxide (SnO2) nanorods by a two-step chemical solution route are reported. Hydrolyzing of MWCNTs and SnCl4·5H2O at a near room temperature followed by alkali-assisted hydrothermal process resulted in perfect SnO2 coating on MWCNTs. Based on the XRD and TEM results, we found the nanoscale SnO2 rods covered densely on MWCNTs.

3D‐Branched ZnO/CdS Nanowire Arrays for Solar Water Splitting and the Service Safety Research

Modulation of broadband light trapping through assembly of 3D structures and modification with narrow band‐gap semiconductors provide an effective way to improve the photoelectrochemical (PEC) performance. Here, 3D‐branched ZnO nanowire arrays (NWAs) modified with cadmium sulfide (CdS) nanoparticles are designed and synthesized via solution chemical routes. The 3D‐branched ZnO NWA–CdS nanoparticle photoanodes show an excellent PEC performance in UV and visible region and the maximum photo‐to‐hydrogen conversion efficiency reaches to 3.1%. The high performance of 3D‐branched ZnO NWA–CdS composites is mainly attributed to the excellent carrier collection capability and high light‐trapping ability of 3D‐branched ZnO NWAs as well as the excellent photocatalytic activity of CdS nanoparticles in the visible region. In addition, the photocorrosion mechanism of 3D‐branched ZnO NWA–CdS photoanodes is systematically investigated, and a protective TiO2 layer is deposited onto the photoanodes to elevate the PEC stability. The results benefit a deeper understanding of the role of 3D‐branched structures decorated with narrow band‐gap semiconductors in solar water splitting.