Ionic Liquid-assisted Hydrothermal Route Research Articles

Ionic liquid as morphology-directing agent of two-dimensional Bi2WO6: New insight into photocatalytic and antibacterial activity

An efficient and durable utilization of light to drive photocatalytic reactions still requires the overcoming of barriers. Herein, two-dimensional (2D) ultrathin IL_Bi2WO6 (IL_BWO) photocatalysts were prepared for the first time via ionic liquid-assisted hydrothermal route by adjusting the amount of tetrabutylammonium chloride [TBA][Cl], synthesis temperature and duration. IL played the role of morphology-directing agent given by selecting the amount of IL, the control of nanosheet thickness was possible. The replacement of IL with KCl resulted in the growth of similar nanostructure, but with higher thickness, while, the absence of Cl− caused the formation of clew-like microspheres. Two different model experiments, phenol degradation, and inactivation of Escherichia coli and Staphylococcus aureus bacteria were chosen to evaluate the photocatalytic activity. The improved photocatalytic performance was attributed to (i) the ultrathin structure, which let for shorter diffusion distance, (ii) the nitrogen presence in the photocatalyst structure, and (iii) the oxygen vacancies formation. The •OH and h+ were the main species involved in the mechanism of photooxidation, and could be also responsible for the enhanced antimicrobial properties. The unique strategy of IL application establishes a new insight for a controllable preparation of 2D Bi2WO6 with improvement photocatalytic and antibacterial properties.

Ionic liquid-assisted hydrothermal synthesis and luminescence properties of Na3Y1−x(PO4)2: xTb3+ phosphors

In this study, a series of spindle-like Na3Y1−x(PO4)2: xTb3+ phosphors have been controllably synthesized by an ionic liquid-assisted hydrothermal route. The structures and morphologies of the as-synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Photoluminescence spectroscopy (PL), fluorescence decay, and temperature-dependent emission spectroscopy were adopted to characterized the luminescence properties of the samples. The excitation spectra of Na3Y1−x(PO4)2: xTb3+ comprised several well-resolved absorption bands at 273, 285, 304, 318, 340, 352, 368, and 378 nm. When excited at 368 nm, Na3Y1−x(PO4)2: xTb3+ phosphors could exhibit emission bands at 490 nm (5D4 → 7F6), 545 nm (5D4 → 7F5), 586 nm (5D4 → 7F4), and 624 nm (5D4 → 7F3), respectively. The concentration quenching occurred when x is beyond 0.22. The decay time of the photoluminescence of Na3Y1−x(PO4)2: xTb3+ decreased with the increase of Tb3+ doping, which demonstrated the existence of energy transfer among Tb3+ ions. The Commission Internationale de L’Eclairage (CIE) chromaticity coordinates of Na3Y0.78(PO4)2: 0.22Tb3+ were (0.3273, 0.5199) at 273 K, which located in the green region. The temperature dependence experiments revealed that the title material had excellent luminescence thermal stability. The luminescence intensity of Na3Y0.78(PO4)2: 0.22Tb3+ phosphor at 473 K declined 22.1% to its initial intensity. The title material could be used as green light-emitting phosphor for cold white LED applications.

Mn doping induced physico-chemical changes in La[sbnd]Ce ferrite nanofabricated by ionic liquid assisted hydrothermal route

Effect of Mn substitution on the structural, optical, surface and magnetic properties of mixed LaFeO3i.e. LaCe nanoferrites (La0.9Ce0.1Fe1-xMnxO3) synthesized by hydrothermal route using ionic liquid surfactant (ILS), 1-hexadecyl-3-methyl imidazolium chloride, [C16mim][Cl], have been explored by X-ray diffraction (XRD), IRaman spectroscopy, Brunauer-Emmett-Teller (BET) adsorption isotherm, Vibrating sample magnetometer (VSM) and Mӧssbauer spectroscopy etc. Incorporation of Mn in crystal lattice of LaCe ferrite induced the structural distortion as specified by structural studies. Morphology and the size of the obtained nanoparticles (NPs) get slightly altered by the quantity of dopant as observed from transmission electron microscopy (TEM). The appearance of rod shaped morphology along with spherical NPs indicates the templating effect of ILS. Surface and magnetic properties of Mn doped LaCe NPs have found to be significantly improved than that of undoped LaCe ferrites. Magnetization of the obtained NPs strongly depends on the content of Mn in the lattice. Enhanced magnetization has been observed up to certain extent of Mn doping (x = 0.3). At higher Mn content (x = 0.5), a significant reduction in magnetization has been observed as revealed from Mӧssbauer and magnetic studies. The enhanced surface area (36.18 m2/g) of the Mn doped samples over the undoped LaCe ferrite opens the new doors in biological and sensing applications.

Ionic liquid assisted hydrothermal synthesis of MoS2 double-shell polyhedral cages with enhanced catalytic hydrogenation activities

MoS2 double-shell polyhedral cages are synthesized via an ionic liquid assisted hydrothermal route and exhibit enhanced catalytic hydrogenation properties.

Novel Synthesis Strategy of γ-AlOOH Nanotubes: Coupling Reaction via Ionic Liquid-Assisted Hydrothermal Route

A novel synthetic strategy, i.e., transition metal ions used to drive a coupling reaction in terms of complex formation of the metal ions and decomposition of a precursor, combined with ionic liquid-assisted hydrothermal route, was utilized to synthesize γ-AlOOH nanotubes with high purity and uniform dimension at a mild condition. These γ-AlOOH nanotubes can be easily transformed to γ-Al2O3 nanotubes by calcining at 600 °C for 2 h, without changing the morphology. More specifically, this strategy may be helpful to develop a new opportunity for synthesis of inorganic nanomaterials with novel morphologies and improved properties.

Photocatalytic activity of Li-doped TiO2 nanoparticles: Synthesis via ionic liquid-assisted hydrothermal route

We have proposed a simple one pot synthesis of lithium-doped TiO2 nanoparticles (TiO2:Li) via an ionic liquid-assisted hydrothermal method and their potential use as a photocatalyst for the degradation of organic dye, as well as the reduction of toxic Cr6+ to non toxic Cr3+. The structure of TiO2:Li nanoparticles was examined by XRD, FTIR, XPS, Raman, UV–vis, Photoluminescence spectroscopy and morphology by SEM and TEM. The incorporation of Li into anatase-phase TiO2 affected the optical properties of the resultant TiO2 nanoparticles. The photocatalytic activity of the TiO2:Li nanoparticles was determined by degradation of trypan blue. Degradation studies showed improved photocatalytic activity of TiO2:Li nanoparticles compared to TiO2 nanoparticles and bulk TiO2. TiO2:Li nanoparticles also functioned as a detoxification agent which was confirmed by the reduction of Cr6+ to Cr3+.

Ionic liquid-modulated preparation of hexagonal tungsten trioxide mesocrystals for lithium-ion batteries.

Hexagonal (h-WO3) mesocrystals with biconical morphology were prepared by a straightforward ionic liquid-assisted hydrothermal route and investigated as anodic materials for lithium-ion batteries. Compared to the alternatives, the biconical tungsten trioxide mesocrystal exhibited excellent lithium insertion with good cyclability and rate capability, making it a promising candidate as the anode material for high-performance lithium-ion batteries.

Ionic liquid-assisted fabrication of copper hydroxyphosphate nanocrystals with exposed {100} facets for enhanced photocatalytic activity

Libethenite Cu2PO4OH nanocrystals with different morphologies were prepared by an ionic liquid-assisted hydrothermal route, and were further investigated as photocatalysts under visible-light irradiation. The Cu2PO4OH elongated truncated bipyramids exposing {100} facets exhibit superior photocatalytic activity compared to other particles, which can be attributed to the presence of 100% Cu5c atoms on {100} facets. It is highly expect this research can provide a useful fundamental understanding of shape-dependent photocatalytic performance of copper hydroxyphosphate.

An ionic liquid route to prepare mesoporous ZrO2–TiO2 nanocomposites and study on their photocatalytic activities

Mesostructured ZrO2–TiO2 nanoparticles with different ZrO2 contents have been synthesized by an ionic liquid-assisted hydrothermal route. The prepared materials were characterized by means of X-ray diffraction (XRD), nitrogen adsorption–desorption, transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra analysis (DRS) and NH3-TPD technique. The obtained ZrO2–TiO2 materials exhibit large specific surface area and uniform pore sizes. Introduction of ZrO2 species can effectively suppress phase transformation from anatase to rutile and promote thermal stability of ZrO2–TiO2 materials. The photocatalytic activity of the ZrO2–TiO2 sample is higher than that of the TiO2 sample and commercially available Degussa P25. The high photocatalytic activity can be attributed to stronger adsorption in the ultraviolet region, higher specific area, smaller crystal size and increased surface OH groups.

Synthesis and characterization of MoS 2 nanostructures with different morphologies via an ionic liquid-assisted hydrothermal route

MoS 2 nanostructures with different morphologies, such as agaric-like, sphere-like and flower-like, were successfully synthesized via a facile ionic liquid-assisted hydrothermal route. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy and energy dispersive X-ray analysis (EDX). XRD patterns showed that the layered structures of the as-prepared MoS 2 samples did not completely form, and after their annealing treatment at 800 °C for 2 h in the atmosphere of N 2/H 2, the MoS 2 products had good crystallinities with well-stacked layered structures. The influences of the ionic liquid on the sizes and morphologies of the MoS 2 nanostructures were discussed. It was found that the as-prepared MoS 2 nanostructures were assembled by nanosheets and the ionic liquid played a crucial role on the formation of the MoS 2 nanostructures in our experiment. A possible formation mechanism of the sphere-like MoS 2 nanostructures was preliminarily presented.

Electrochemical lithiation/delithiation performances of 3D flowerlike MoS 2 powders prepared by ionic liquid assisted hydrothermal route

3D (three-dimensional) flowerlike MoS 2 was fabricated by hydrothermal synthesis assisted with an ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4]), and characterized by XRD (X-ray diffractometer) and FESEM (field-emission scanning electron microscopy). It was found that the ionic liquid played a crucial role on MoS 2 morphology. The MoS 2 prepared with IL-assisted hydrothermal route was 3D flowerlike architecture, which was built from MoS 2 nanoflakes. The MoS 2 prepared without IL was nanosheets overlaped each other. Both of the as-prepared MoS 2 samples were mainly amorphous. The 3D flowerlike MoS 2 prepared with IL-assisted hydrothermal route exhibited significantly enhanced the electrochemical lithiation/delithiation performances. Its reversible capacity and cycling durability were better than those of the MoS 2 nanosheets prepared without IL. Although, the MoS 2 samples with high crystallinity could be gained by their annealing at 800 °C in the atmosphere of N 2/H 2, the annealing lead to great decrease in their electrochemical lithiation/delithiation capacity and cycling durability.