Synthesis and characterization of superfine pure tetragonal nanocrystalline sulfated zirconia powder by a non-alkoxide sol–gel route

Highly Foldable, Super-Sensitive, and Transparent Nanocellulose/Ceramic/Polymer Cover Windows for Flexible OLED Displays

Polymer cover windows are important components of flexible OLED displays but they easily generate wrinkles because of their weak folding resistance. Increasing the polymer thickness can improve the folding resistance but it decreases the touch sensitivity. Thus, fabricating highly foldable and supersensitive polymer cover windows is still challenging. Here, by incorporating cellulose nanocrystals (CNCs) and zirconia (ZrO₂) into colorless polyimide (CPI), we developed a highly foldable and supersensitive hybrid cover window. Inspired by the theory of elasticity, we added rigid CNCs into CPI to improve the elastic modulus and hence the foldability. ZrO₂ was introduced to improve dielectric properties, which leads to improved touch sensitivity. After these modifications, the elastic modulus of the cover windows was increased from 1432 to 2221 MPa, whereas its dielectric constant was increased from 2.95 to 3.46 (@1 × 10⁶ Hz), resulting in significantly enhanced foldability and sensitivity. Meanwhile, because of the nano size of CNCs and ZrO₂, the hybrid cover windows exhibit excellent optical properties with the transmittance of ∼88.1%@550 nm and haze of 2.39%. With improved and balanced mechanical, dielectric, and optical properties, these hybrid cover windows overcome current cover windows' defects and could be widely used in next-generation flexible displays.

Sulfated zirconium oxide-decorated magnetite KCC-1 as a durable and recyclable adsorbent for the efficient removal of asphaltene from crude oil

Sulfated zirconium oxide (ZrO₂/SO₄ ^2-) as a highly durable acidic reagent was immobilized on magnetite KCC-1 nanoparticles (Fe₃O₄@SiO₂/KCC-1@ZrO₂/SO₄ ^2- NPs), and the resulting hybrid was used as a highly efficient recyclable adsorbent for the adsorption and removal of asphaltene from crude oil. The presence of ZrO₂/SO₄ ^2- groups not only promotes the adsorption capacity, but also helps recycle the adsorbents without any significant efficiency loss arising from its high chemical resistance. The results showed an obvious synergistic effect between the magnetic core (Fe₃O₄ NPs), fibrous silica (KCC-1) and the sulfated zirconium oxide groups with high correlation for asphaltene adsorption. The effective parameters in asphaltene adsorption, including initial asphaltene concentration, catalyst concentration and temperature, were investigated. Maximum adsorption occurred in the presence of 0.7 g L^-1 of the adsorbent, at a concentration of 2000 mg L^-1 of asphaltene. The asphaltene adsorption by NPs follows a quasi-second order adsorption kinetics. Asphaltene adsorption kinetics were studied by Langmuir, Freundlich, and Temkin isotherms. The prominent advantage of the adsorbent is its ability to be recovered after each adsorption by acid treatment, so that no significant reduction in adsorbent adsorption activity was observed, which can be directly attributed to the presence of ZrO₂/SO₄ ^2- groups in the hybrid.

Hydrogen Yield from CO2 Reforming of Methane: Impact of La2O3 Doping on Supported Ni Catalysts

Development of a transition metal based catalyst aiming at concomitant high activity and stability attributed to distinguished catalytic characteristics is considered as the bottleneck for dry reforming of methane (DRM). This work highlights the role of modifying zirconia (ZrO2) and alumina (Al2O3) supported nickel based catalysts using lanthanum oxide (La2O3) varying from 0 to 20 wt% during dry reforming of methane. The mesoporous catalysts with improved BET surface areas, improved dispersion, relatively lower reduction temperatures and enhanced surface basicity are identified after La2O3 doping. These factors have influenced the catalytic activity and higher hydrogen yields are found for La2O3 modified catalysts as compared to base catalysts (5 wt% Ni-ZrO2 and 5 wt% Ni-Al2O3). Post-reaction characterizations such as TGA have showed less coke formation over La2O3 modified samples. Raman spectra indicates decreased graphitization for La2O3 catalysts. The 5Ni-10La2O3-ZrO2 catalyst produced 80% hydrogen yields, 25% more than that of 5Ni-ZrO2. 5Ni-15La2O3-Al2O3 gave 84% hydrogen yields, 8% higher than that of 5Ni-Al2O3. Higher CO2 activity improved the surface carbon oxidation rate. From the study, the extent of La2O3 loading is dependent on the type of oxide support.

NiFe2O4@SiO2@ZrO2/SO42−/Cu/Co nanoparticles: a novel, efficient, magnetically recyclable and bimetallic catalyst for Pd-free Suzuki, Heck and C–N cross-coupling reactions in aqueous media

The novel heterogeneous bimetallic nanoparticles of Cu–Co were synthesized and successfully applied as a recyclable magnetically catalyst in Heck, Suzuki, and C–N cross-coupling via a quick, easy, efficacious and environmentally protocol.

Macrophage membrane coated persistent luminescence nanoparticle@MOF-derived mesoporous carbon core-shell nanocomposites for autofluorescence-free imaging-guided chemotherapy

Efficient drug nanocarriers with high drug loading capacity and luminescent ability are in high demand for biomedical applications. Here we show a facile and bio-friendly synthesis of macrophage membrane coated persistent luminescence nanoparticle (PLNP)@metal-organic framework (MOF)-derived mesoporous carbon (MC) core-shell nanocomposites (PLMCs) for autofluorescence-free imaging-guided chemotherapy. MOF UiO-66 is used as both the precursor and the template, and is controllably coated on the surface of the PLNP to form a PLNP@UiO-66 core-shell composite. Subsequent calcination enables the transformation of PLNP@UiO-66 to PLMC due to the pyrolysis of the UiO-66 shell. PLMC with a small particle size of 70 nm, a tunable large pore size from ∼4.8 to ∼16.2 nm in the shell and near-infrared persistent luminescence in the core was prepared by controlling the calcination conditions. The prepared PLMC showed an enhanced drug loading capacity for three model drugs (doxycycline hydrochloride, acetylsalicylic acid, and paclitaxel) compared with PLNP@UiO-66. Further coating of the macrophage membrane on the surface of PLMC results in MPLMC with enhanced cloaking ability for evading the mononuclear phagocyte system. The drug-loaded MPLMC is promising for autofluorescence-free persistent luminescence imaging-guided drug delivery and tumor therapy.

Hydrothermal preparation of a platinum-loaded sulphated nanozirconia catalyst for the effective conversion of waste low density polyethylene into gasoline-range hydrocarbons

A platinum-loaded sulphated nanozirconia (Pt/nano ZrO₂–SO₄) bifunctional metal–acid catalyst was synthesized using a hydrothermal process. The nano ZrO₂–SO₄ was initially prepared by dispersing the nano ZrO₂ in H₂SO₄, followed by wet impregnation via heating in an aqueous PtCl₄ solution. This material was subsequently calcined and reduced under hydrogen gas to produce the catalyst. The Pt/nano ZrO₂–SO₄ was found to be a highly active, selective and stable solid acid catalyst for the conversion of waste low density polyethylene (LDPE) to high value hydrocarbons. The catalytic activity and stability of this material were evaluated during the hydrocracking of waste LDPE while optimizing the reaction temperature, time and catalyst-to-feed ratio. The activity of catalyst prepared by hydrothermal was attributed to highly dispersion of Pt species interacting with the support and inhibition of the agglomeration process. The impregnation method of hydrothermal generated highly active and selective catalyst with Pt loads of 1 wt%. The hydrocracking of waste LDPE over Pt/nanoZrO₂–SO₄ at 250 °C for 60 min with a catalyst-to-feed proportion of 1 wt% gave the largest gasoline fraction.

A Pt/nano ZrO₂–SO₄ bifunctional metal–acid catalyst was synthesized using a hydrothermal process.

The CuFe2O4@SiO2@ZrO2/SO42−/Cu nanoparticles: an efficient magnetically recyclable multifunctional Lewis/Brønsted acid nanocatalyst for the ligand- and Pd-free Sonogashira cross-coupling reaction in water

Herein, the synthesis and application of copper-incorporated sulfated zirconium oxide supported on CuFe₂O₄ NPs (CuFe₂O₄@SiO₂@ZrO₂/SO₄²⁻/Cu NPs) as a novel Lewis/Brønsted acid nanocatalyst were studied for the Sonogashira C–C cross-coupling reaction. The fabricated CuFe₂O₄@SiO₂@ZrO₂/SO₄²⁻/Cu catalyst exhibited efficient activity for a large variety of aryl iodides/bromides and, most importantly, aryl chlorides in water and in the presence of NaOH as a base in short reaction times. The catalyst was fully characterized by FTIR, TG-DTG, VSM, XRD, EDX, FE-SEM and TEM analyses. A synergetic effect could be considered to have arisen from the various Lewis acid and Brønsted acid sites present in the catalyst. The efficient incorporation of copper into zirconia provided a robust highly stable hybrid, which prevented any metal leaching, whether from the magnetite moiety and/or Cu sites in the reaction mixture. Moreover, the catalyst was successfully recovered from the mixture by a simple external magnet and reused for at least 9 consecutive runs. Zero metal leaching, stability, consistency with a variety of substrates, fast performance, cost-effectiveness, environmental friendliness, and preparation with accessible and cheap materials are some of the advantages and highlights of the current protocol.

A mild and green protocol was developed by immobilizing copper-incorporated sulfated zirconium oxide on CuFe₂O₄ as an efficient inorgano-nanocatalyst for the Sonogashira reaction.

Good Biocompatibility and Sintering Properties of Zirconia Nanoparticles Synthesized via Vapor-phase Hydrolysis

ZrO2 nanoparticles were synthesized by a vapor-phase hydrolysis process, and characterized in terms of crystalline structures, hardness and microstructures by X-ray diffraction, Vickers hardness test method, and atomic force microscopy (AFM) measurements. Moreover, in vitro cytotoxicity evaluation and hemolysis assay showed that the nanoparticles possessed good biocompatibility. Hardness investigations and AFM measurements indicated that both the sintering temperature and compression force played an important role in determining the physical behaviors (hardness, roughness and density) of flakes of the ZrO2 nanoparticles. When ZrO2 nanoparticles synthesized at 500 °C were pressed into flakes under 6 MPa and sintered at 1400 °C, the resulting flakes exhibited an optimal combination of hardness (534.58 gf·mm-2), roughness (0.07 μm) and density (4.41 g·cm-3). As the Vickers hardness value of human bones is of 315~535 gf·mm-2 and the density of adult femuris about 1.3~1.7 g·cm-3, the experimental results showed that the ZrO2 flakes were comparable to human bones with a higher density. As a result, the synthesized ZrO2 NPs may be useful for biomedical applications, especially for bone repair and replacement in future.

Synthesis of flower-shaped ZrO2–C composites for adsorptive removal of trichlorophenol from aqueous solution

A novel kind of nanoflake zirconia–carbon (ZrO₂–C) composite exhibited a much improved capacity to adsorb TCP.

Microwave synthesis, characterization, and photoluminescence properties of nanocrystalline zirconia

We report synthesis of ZrO₂ nanoparticles (NPs) using microwave assisted chemical method at 80°C temperature. Synthesized ZrO₂ NPs were calcinated at 400°C under air atmosphere and characterized using FTIR, XRD, SEM, TEM, BET, and EDS for their formation, structure, morphology, size, and elemental composition. XRD results revealed the formation of mixed phase monoclinic and tetragonal ZrO₂ phases having crystallite size of the order 8.8 nm from most intense XRD peak as obtained using Scherrer formula. Electron microscope analysis shows that the NPs were less than 10 nm and highly uniform in size having spherical morphology. BET surface area of ZrO₂ NPs was found to be 65.85 m²/g with corresponding particle size of 16 nm. The band gap of synthesized NPs was found to be 2.49 eV and PL spectra of ZrO₂ synthesized NPs showed strong peak at 414 nm, which corresponds to near band edge emission (UV emission) and a relatively weak peak at 475 and 562 nm.