Porous Nanohybrid Research Articles

Facile Synthesis of Hybridized Mesoporous Au@TiO2/SnO2as Efficient Photocatalyst and Selective VOC Sensor

Considering the novelty of heterojunction formation in sunlight photocatalysis, dahlia flower resembling Au loaded TiO2/SnO2 nanocomposite was synthesized using facile hydrothermal method to improve the degradation rate of waste water pollutants. The intrinsic high surface area coupled with unique heterojunction formation causes Au@TiO2/SnO2 to exhibit excellent photocatalytic activity towards the degradation of Rhodamine B (RhB) dye under sunlight irradiation. Under the optimized conditions of catalyst dosage (0.3 g/L), dye concentration (100 ppm) and pH (10), 99.2 % of the RhB aqueous solution was degraded in 35 min of illumination time. Moreover, the resulting Au@TiO2/SnO2 nanohybrid unveiled excellent sensing response (43) towards acetone gas (100 ppm) while detecting a variety of common volatile organic compounds (VOCs) including methanol, benzyl alcohol and isopropanol at 220 °C. Thus, the enhanced photocatalytic activity for degrading organic pollutants under sunlight irradiation and excellent sensing properties at relatively lower working temperature, make this porous nanohybrid a promising candidate for environmental monitoring applications.

Highly Efficient Visible Light-Induced O2 Generation by Self-Assembled Nanohybrids of Inorganic Nanosheets and Polyoxometalate Nanoclusters

Unusually high photocatalytic activity of visible light-induced O2 generation can be achieved by electrostatically-derived self-assembly between exfoliated Zn-Cr-LDH 2D nanosheets and POM 0D nanoclusters (W7O246− and V10O286−) acting as an electron acceptor. This self-assembly can provide a high flexibility in the control of the chemical composition and pore structure of the resulting LDH-based nanohybrids. The hybridization with POM nanoclusters remarkably enhances the photocatalytic activity of the pristine Zn-Cr-LDH, which is attributable to the formation of porous structure and depression of charge recombination. Of prime interest is that the excellent photocatalytic activity of the as-prepared Zn-Cr-LDH-POM nanohybrid for visible light-induced O2 generation can be further enhanced by calcination at 200 °C, leading to the very high apparent quantum yield of ∼75.2% at 420 nm. The present findings clearly demonstrate that the self-assembly of LDH–POM is fairly powerful in synthesizing novel LDH-based porous nanohybrid photocatalyst for visible light-induced O2 generation.

Visible-light photocatalytic activity of mesoporous nanohybrid assembled by tantalotungstate nanosheets and manganese ions

Abstract Manganese-intercalated layered tantalotungstates have been assembled by tantalotungstate nanosheets with manganese ions via an exfoliation–restacking route. The as-prepared nanohybrids are mesoporous with specific surface areas more than 36 m 2 /g and the mesopores are originated from the house-of-cards-type stacking of the intercalated crystallites. Introducing manganese ions into the intersheeted regions allows the nanohybrids to exhibit distinct spectral responses in visible-light region with band gaps less than 2.54 eV. The porous nanohybrids exhibit high photocatalytic activities in the degradation of methylene blue under visible-light irradiation.

Study on the Structural and Photocatalytic Properties for Pore Size Tailored SnO2-Pillared Layered Titanate Nanohybrids

A new mesoporous SnO2-pillared layered titanate is prepared by hybridizing the exfoliated titanate nanosheets with SnO2 nanosol particles. The pore size tailored porous nanohybrids (SBET = 74 approximately 280 m2/g and d = 18 approximately 96 angstroms) are obtained after calcining an as-prepared sample. The mesoporous nanohybrids exhibited different photocatalytic behaviors for salicylic acid and methylene blue depending upon their crystallinity and porous structure.

Pre-swelled nanostructured electrode for lithium ion battery: TiO2-pillared layered MnO2

Porous structure of layered manganate pillared with titania nanoparticles has been realized by the exfoliation and reassembling route. First, the layered protonic manganese oxide, H0.13MnO2·0.7H2O, is exfoliated by the intercalation of tetrabutylammonium (TBA) ions, and then the exfoliated manganate nanosheets are reassembled in the presence of titania nanoparticles, which results in porous nanohybrid materials. X-Ray diffraction (XRD), cross-sectional transmission electron microscopy (TEM), and Mn K-edge X-ray absorption spectroscopy (XAS) analyses clearly show that the titania nanoparticles with a diameter of 1 nm are successfully intercalated into the two dimensional manganate lattice without any deterioration of electronic structure and local symmetry of Mn ion. According to the N2 adsorption–desorption isotherms, the present nanohybrid is determined to be highly porous with a high specific surface area (106 m2 g−1), which is 10 times larger than that (11 m2 g−1) of the pristine. Finally, electrochemical experiments demonstrate that the specific capacity of the present pillared material is 288 mA h g−1, which is significantly larger than the theoretical value (193 mA h g−1) from the physical mixture of the pristine potassium birnessite and titania nanoparticles.

Surface dyeability of cotton and nylon fabrics coated with a novel porous silk fibroin/silica nanohybrid

AbstractA new and facile approach of surface dyeing was developed for cotton and nylon fabrics coated with a novel porous silk fibroin (SF)/silica (SiO2) nanohybrid. Actually, dyeing of the fabrics occurred in the very thin nanohybrid layers exclusively, while the main body of the fabrics remained intact on the whole. With the assistance of the large surface areas of the porous nanohybrid, dye uptake of the coated cotton fabrics dyed with Acid Red GSF or Disperse Cation Red SD‐GRL was enhanced substantially compared with that of the uncoated fabrics as a control. Moreover, dye uptake increased with the SF content in the hybrid, indicating that the SF moiety played a significant role for the surface dyeing process. Color fastness to water of both the dyestuffs was much higher for the coated cotton fabrics compared with that of the uncoated ones. Similar results were obtained for the nanohybrid coated nylon fabrics dyed with Disperse Cation Red SD‐GRL as those of the coated cotton fabrics. However, no increase was observed for dye uptake of the coated nylon fabrics dyed with Acid Red GSF owing to saturation of the dyestuff attached on the controlled uncoated nylon fabrics, which concealed the contribution of the nanohybrid layer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Structural evolution of SiO2–ZrO2 nano-sol intercalated clays upon pillaring reactionElectronic supplementary information (ESI) available: BJH pore size distribution and k3-weighted EXAFS spectra of the SiO2–ZrO2 sol-pillared clay at different calcination temperatures. See http://www.rsc.org/suppdata/jm/b2/b208929g/

A two-dimensional layered nanohybrid with a high specific surface area has been prepared by ion exchange reactions between the sodium ions in montmorillonite and the positively charged Zr-coated SiO2 sol particles. The basal spacing increases from 12.5 A to 26 A upon intercalation due to the insertion of a SiO2–ZrO2 nano-sol into the interlayer space of montmorillonite. Upon calcining at 300 °C, it transforms into a porous nanohybrid with a basal spacing of 22.6 A. The N2 adsorption–desorption isotherms were characterized as being of type IV according to the BDDT classification, indicating the existence of a large number of micro- and mesopores. From its hysteresis curves, one can classify the nanohybrid as being of the H3 type with slit-shaped pores by the IUPAC classification. The estimated BET specific surface area and average micropore size are about 358 m2 g−1 and 12 A, respectively, with the latter value is similar to the gallery height of the sample indicating that the SiO2–ZrO2 sol particles are intercalated to form a monolayer. The local structural evolution of the Zr species in SiO2–ZrO2 sol particle has been investigated systematically by X-ray absorption spectroscopy at the Zr K-edge with respect to the calcination temperature. The EXAFS spectroscopic results confirm that the surface of the nano-sized SiO2 sol particles is coated with the Zr species.