A fluorinated silyl functionalized zirconia was synthesized by the sol-gel method to fabricate an extremely durable superhydrophobic coating on cotton fabrics by simple immersion technique. The fabric surfaces firmly attached with the coating material through covalent bonding, possessed superhydrophobicity with high water contact angle ≈163 ± 1°, low hysteresis ≈3.5° and superoleophilicity. The coated fabrics were effective to separate oil/water mixture with a considerably high separation efficiency of 98.8 wt% through ordinary filtering. Presence of highly stable (chemically and mechanically) superhydrophobic zirconia bonded with cellulose makes such excellent water repelling ability of the fabrics durable under harsh environment conditions like high temperature, strong acidic or alkaline solutions, different organic solvents and mechanical forces including extensive washings. Moreover, these coated fabrics retained self-cleanable superhydrophobic property as well as high water separation efficiency even after several cycles, launderings and abrasions. Therefore, such robust superhydrophobic ZrO2 coated fabrics have strong potential for various industrial productions and uses.
A Pd-Ni alloy nanoparticle (NP) doped mesoporous SiO2 film was synthesized using a one pot inorganic-organic sol-gel process in the presence of structure director P123. Pure Pd and Ni NP containing films were also synthesized as controls. Overall a composition of 10 mol% metal (in the case of Pd-Ni, 5 mol% of each metal) and 90 equivalent mol% SiO2 was maintained in the heat-treated films. Grazing incidence X-ray diffraction and transmission electron microscopy studies of the final heat-treated Pd-Ni doped films revealed the (111) oriented growth of the Pd-Ni alloy NPs, with an average size of 5.3 nm, residing inside the mesopores of the SiO2 film. We performed the C-C coupling reaction employing the film-catalysts and the progress of the reaction was monitored using a fluorimeter. Overall, only the Pd-Ni alloy NP doped film showed good catalytic activity with excellent recyclability. It has been determined that the higher oxidising ability of metallic Ni restricted the oxidation of Pd in the Pd-Ni alloy catalyst under the reaction conditions, leading to the maintained reusability in consecutive cycles.
cycling especially on fast changing rate due to their low lithium intercalation potential (≈0.1 V vs Li/Li + ), resulting the risk of short circuit that may end up with thermal explosion. [7] Whereas, in case of TiO 2 anode materials, not only its relatively high discharge potential (≈1.7 V vs Li/Li + ) suppresses the formation of lithium dendrites but also its low volume expansion during lithiation/delithiation improves long cycling durability and inhibits the formation of solid electrode interface. [8,9] Thus these two aspects of TiO 2 synergistically facilitate superior safety of batteries along with a theoretical capacity of ≈170 mAh g -1 which is comparable with the commercialized cathode material. [10] Additionally, TiO 2 materials are of low cost, nontoxic, chemically and thermally stable. All these properties make TiO 2 advantageous anode material for lithium ion battery application. Unfortunately, the electrochemical performances of TiO 2 is still challenging due to its low electronic conductivity and Li-ion diffusivity inducing a poor rate capability. [11] In addition to that, uses of TiO 2 nanoparticle anodes are restricted by other several issues like particle agglomeration and dissolution during cycling that result in decrease in electroactive area and performance degradation. Present research on this field has made considerable effort to fabricate dimensionally controlled nanostructured TiO 2 with high surface area to enhance the energy storage performances. [12,13] This is because nanostructured materials offer shortening of Li + diffusion path, large interfacial active area, and also possess the ability to relax the strain generated during Li + insertion/extraction process. [14][15][16] In this perspective 1D nanomaterials such as nanotubes or nanofibers are good choice to satisfy all these criteria due to their large specific surface area and high aspect ratio (surface to volume ratio) which assure favorable transport of both the electrons and Li + . [3,17,18] On the other side, porosity within the structure not only enables high rate capability by decreasing the polarization resistance but also it allows easy access of active sites for Li + , electrons and electrolyte resulting improved kinetics favorable for better cycle performance and storage capacity. [19][20][21] Moreover, Li storage performances in The authors report a novel strategy to fabricate electrospun anatase TiO 2 -rGO composite nanofibers with 3D cubic ordered mesoporosity. Such synthesis route not only ensures molecular level composite formation between rGO and TiO 2 but also retains the rGO content and orders mesostructure after calcination of the nascent fiber at an optimum condition that only removes the surfactant and polymer. Transmission electron microscopic and low angle X-ray diffraction studies confirm the presence of ordered mesoporosity within the nanofibers. Raman and X-ray photoelectron spectroscopy studies reveal the molecular level composite formation between rGO and TiO 2 with chemical bonding. This composite nano...
Although trimethylsilyl functionalized SiO 2 derived films show excellent superhydrophobicity, their adhesion and abrasion resistant properties are extremely poor. In this study, a new approach has been shown to improve the adhesion and abrasion properties of such films. A neutral and relatively hydrophobic [Zn(CH 3 OO) 2 (H 2 O) 2 ] complex solution has been used to interact with the superhydrophobic silica gel nanoparticle dispersion. After dip-coating, the composite sol yielded films of a zinc acetate/superhydrophobic silica composite network while the hydrophilic part (bonded water) associated with Zn helps in binding the hydroxyl groups (silanols) present on the glass surface. The composite films were heat-treated at 300-400 C in a nitrogen atmosphere in order to obtain transparent and superhydrophobic ZnO-SiO 2 nanocomposite films. The decomposition of zinc acetate formed ZnO nanocrystallites and remained attached with the hybrid silica matrix. These films showed excellent water repellency (water contact angle, CA z 158 AE 7 ; hysteresis z 4 ) with good adhesion and abrasion resistant properties. XRD, Raman and TEM studies confirm the existence of ZnO nanocrystallites in the composite films. Owing to the stability of hydrophobic methyl groups attached with silicon at relatively high temperature in a nitrogen atmosphere, these ZnO-SiO 2 nanocomposite films remain superhydrophobic even after a heat-treatment at 400 C.
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