Songwei  Lu

Nanoporous and Nanostructured Materials for Catalysis, Sensor, and Gas Separation Applications

Titanium oxide nanotubes are prepared and treated with Au (Au/nanotube sample) and Pt (Pt/nanotube sample), and the photoactivity of these catalysts compared to a standard Degussa P25 photocatalyst is investigated.  The samples were analyzed using X-ray diffraction, field emission gun scanning transmission electron microscopy (STEM). Both high-resolution TEM images and high-angle annular dark-field (HAAD) images were recorded for the specimens. Oxidation of acetaldehyde was used to test the efficiency of the catalysts. Nanotube samples showed better photoactivity than the standard P25, because the P25 titania deactivates quickly. Enhanced reactivity of the nanotube is related to surface charge polarity developed on outer and inner surfaces due to the difference in overlap of oxygen anions that resulted from curving of octahedral sheets. A tentative and qualitative surface polarity model is proposed for enhancing electron-hole pair separation. The inner surface benefits reduction; whereas, the outer surface benefits oxidation reactions. Both the metal identity and the size of the metal particles in the nanotubes affected the photocatalytic activity. Specifically, the addition of platinum increased the activity significantly, and increased the total yield. The addition of gold had lesser impact compared to the platinum. Formation of Pt large nanoparticles on the nanotube surfaces reduces the oxidation reactivity.

Huifang Xu

Ganesh Vanamu

Ziming Nie

Hiromi Konishi

Rakesh Yeredla

Jonathan Phillips

Yifeng Wang

Photocatalytic Oxidation of a Volatile Organic Component of Acetaldehyde Using Titanium Oxide Nanotubes

A high-pressure microwave reactor was used to study the hydrothermal synthesis of
zirconia powders doped with 1 mol <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>%</mml:mi></mml:math> Pr. The synthesis was performed in the pressure range
from 2 to 8 MPa corresponding to a temperature range from 215<mml:math id="E2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mtext>C</mml:mtext><mml:mo>∘</mml:mo></mml:mrow></mml:math> to 305<mml:math id="E3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mtext>C</mml:mtext><mml:mo>∘</mml:mo></mml:mrow></mml:math>. This technology
permits a synthesis of nanopowders in short time not limited by thermal inertia of the vessel.
Microwave heating permits to avoid contact of the reactants with heating elements, and is thus
particularly well suited for synthesis of doped nanopowders in high purity conditions.
A mixture of <mml:math id="E4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>ZrO</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> particles with tetragonal and monoclinic crystalline phases, about 15 nm in size, was obtained.
The p/T threshold of about 5-6 MPa/265–280<mml:math id="E5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mtext>C</mml:mtext><mml:mo>∘</mml:mo></mml:mrow></mml:math> was necessary to obtain good quality of
zirconia powder. A new method for quantitative description of grain-size distribution was applied, which is
based on analysis of the fine structure of the X-ray diffraction line profiles. It permitted to
follow separately the effect of synthesis conditions on the grain-size distribution of the
monoclinic and tetragonal phases.

A. Opalinska

C. Leonelli

W. Lojkowski

R. Pielaszek

E. Grzanka

T. Chudoba

H. Matysiak

T. Wejrzanowski

K. J. Kurzydlowski

Effect of Pressure on Synthesis of Pr-Doped Zirconia Powders Produced by Microwave-Driven Hydrothermal Reaction

We report the study of epoxy-carbazole polymeric network (ECzPN) nanolayers as a
hole injection/transport layer in organic light-emitting devices. The ECzPN nanolayers
were prepared by the thermal curing reaction of epoxidized cresol novolak and 3,6-
diaminocarbazole in the presence of catalytic amount of triphenyl phosphine. The
curing reaction was examined with Fourier transformed infrared spectroscopy, whilst the
thermal stability was studied with thermogravimetric analysis. Optical absorption and
emission spectroscopy were employed to investigate the optical properties of ECzPN
nanolayers, whilst atomic force microscopy was used to examine the surface
nanomorphology of ECzPN nanolayers. The result showed that the device performance
was greatly influenced by the weight ratio of monomers, because the highest occupied
molecular orbital level of ECzPN was significantly changed with the ratio. This is
attributed to the ground-state complexes induced by the specific interaction (hydrogen
bonding) between the lone pair electrons in amines of carbazole moieties and the
hydroxyl group of ring-opened epoxide moieties.

Jin-Woo Park

Eung-Kyoo Lee

Myon Cheon Choi

Hwajeong Kim

Jihwan Keum

Chang-Sik Ha

Youngkyoo Kim

Epoxy-Carbazole Polymeric Network Nanolayers for Organic Light-Emitting Devices

Submicron scale vanadia/silica hybrid nanofiber mats have been produced by electrospinning silica sol-gel precursor containing vanadium oxytriisopropoxide (VOTIP), followed by calcinations at high temperature. The properties of the resulting inorganic hybrid nanofiber mats are compared to those of electrospun pure silica nanofibers. SEM images show fibers are submicron in diameter and their morphology is maintained after calcination. Physisorption experiments reveal that silica nanofiber mats have a high specific surface area of 63 m2/g. FT-IR spectra exhibit Si—O vibrations and indicate the presence of V2O5 in the fibers. XPS studies reveal that the ratio of Si to O is close to 0.5 on the surface of fibers and the amount of vanadium on the surface of fibers increases with calcination. XRD diffraction patterns show that silica nanofibers are amorphous and orthorhombic V2O5 crystals have formed after calcination. EFTEM images demonstrate the growth of crystals on the surface of fibers containing vanadium after calcination. SEM images of fibers with high-vanadium content (50 mol<mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>%</mml:mi></mml:math> V: Si) show that vanadia crystals are mostly aligned along the fiber axis. XPS shows an increase in vanadium contents at the surface, and XRD patterns exhibit an increase in the degree of crystallinity. A coaxial electrospinning scheme has successfully been employed to selectively place V2O5 in the skin layer.

Jeanne E. Panels

Yong Lak Joo

Incorporation of Vanadium Oxide in Silica Nanofiber Mats via Electrospinning and Sol-Gel Synthesis

Mesoporous silicon structures are fabricated during an anodization process of highly doped n-type silicon in hydrofluoric acid solution. The resulting pores are oriented perpendicular to the surface and exhibit a diameter of about 50 nm and a length up to 50
 <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>μ</mml:mi></mml:math>m, controlled by the etching time. The growth of the pores is self-organized and depends on the crystal orientation of the used silicon wafer. The achieved channels, highly oriented along the (100) direction, are filled with nickel in a second electrochemical step. The deposition process leads to a distribution between high aspect ratio Ni-wires and Ni-particles of the incorporated metal. This achieved (porous silicon/Ni)-nanocomposite system exhibits a twofold switching behavior of the magnetization curve at two different field ranges. This property gives rise to high-magnetic field sensor applications based on a silicon technology.

P. Granitzer

K. Rumpf

H. Krenn

Ferromagnetic Nanostructures Incorporated in Quasi-One-Dimensional Porous Silicon Channels  Suitable for Magnetic Sensor Applications

Nanoporous films of core-shell iron nanoclusters have improved possibilities for remediation, chemical reactivity rate, and environmentally favorable reaction pathways. Conventional methods often have difficulties to yield stable monodispersed core-shell nanoparticles. We produced core-shell nanoclusters by a cluster source that utilizes combination of Fe target sputtering along with gas aggregations in an inert atmosphere at <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mn>7</mml:mn><mml:mo>∘</mml:mo></mml:msup><mml:mtext>C</mml:mtext></mml:mrow></mml:math>. Sizes of core-shell iron-iron oxide nanoclusters are observed with transmission electron microscopy (TEM). The specific surface areas of the porous films obtained from Brunauer-Emmett-Teller (BET) process are size-dependent and compared with the calculated data.

Jiji Antony

Joseph Nutting

Donald R. Baer

Daniel Meyer

Amit Sharma

You Qiang

Size-Dependent Specific Surface Area of Nanoporous Film Assembled by Core-Shell Iron Nanoclusters

Pores in single-crystalline semiconductors can be produced in a wide range of geometries and morphologies, including  the “nanometer” regime. Porous semiconductors may have properties completely different from the bulk, and metamaterials with, for example, optical properties not encountered in natural materials are emerging. Possible applications of porous semiconductors include various novel sensors, but also more “exotic” uses as, for example, high explosives or electrodes for micro-fuel cells. The paper briefly reviews pore formation (including more applied aspects of large area etching), properties of porous semiconductors, and emerging applications.

Helmut Föll

Jürgen Carstensen

Stefan Frey

Porous and Nanoporous Semiconductors and Emerging Applications

The latest progresses of the series of research on the trapper of nitrosamines are reported in this paper, involving the attempts to elevate the selective adsorption of zeolites through enhancing adsorbent-adsorbate interaction, in order to prepare the new functional nanoporous materials with high efficiency to eliminate the carcinogenic pollutants in environment and to protect public health. Incorporation of metal oxide such as copper oxide in NaY accelerated adsorption of volatile nitrosamines and anthracene, and moreover, coating zirconia onto the zeolite could dramatically suppress the release of nitrogen oxides in the decomposition of <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>N</mml:mi></mml:math>-nitrosopyrrolidine (NPYR) during temperature-programmed surface reaction (TPSR) process.

Ting Ting Zhuang

Jia Hui Xu

Jia Rong Xia

Yi Cao

Shi Lu Zhou

Ying Wang

Yuan Chun

Jian Hua Zhu

New Development in Nanoporous Composites: Novel Functional Materials for Capturing Nitrosamines in Airstreams

Nanostructured colloidal semiconductors with heterogeneous photocatalytic
behavior have drawn considerable attention over the past few years. This is due to their
large surface area, high redox potential of the photogenerated charge carriers, and
selective reduction/oxidation of different classes of organic compounds. In the present
paper, we have carried out a systematic synthesis of nanostructured CdS-<mml:math id="E2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>TiO</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> via reverse
micelle process. The structural and microstructural characterizations of the as-prepared CdS-<mml:math id="E3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mtext>TiO</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> nanocomposites are determined using XRD and SEM-EDS techniques. The
visible light assisted photocatalytic performance is monitored by means of degradation of
phenol in water suspension.

Sesha S. Srinivasan

Jeremy Wade

Elias K. Stefanakos

Visible Light Photocatalysis via CdS/<svg style="vertical-align:-3.27605pt" height="15.675" version="1.1" viewBox="0 0 32.512501 15.675" width="32.512501" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,11.537)"><path id="x54" d="M592 498l-30 -3q-13 63 -31 89q-13 19 -33.5 25.5t-75.5 6.5h-70v-493q0 -60 16 -75.5t86 -19.5v-28h-286v28q68 4 83.5 19.5t15.5 75.5v493h-62q-60 0 -83 -7t-33 -24q-12 -17 -32 -90h-29q10 116 12 180h20q10 -16 21 -20.5t34 -4.5h395q19 0 28.5 5t21.5 20h21&#xA;q2 -89 11 -177z" /></g><g transform="matrix(.017,-0,0,-.017,8.868,11.537)"><path id="x69" d="M135 536q-20 0 -35 15.5t-15 35.5q0 22 15 37t36 15t35.5 -15t14.5 -37q0 -21 -15 -36t-36 -15zM252 0h-220v26q48 5 59 17t11 63v206q0 47 -9 58t-54 18v24q78 12 142 39v-345q0 -51 11.5 -63t59.5 -17v-26z" /></g><g transform="matrix(.017,-0,0,-.017,13.424,11.537)"><path id="x4F" d="M381 665q131 0 226.5 -93t95.5 -239q0 -158 -96 -253t-238 -95q-137 0 -231 95t-94 238q0 142 92.5 244.5t244.5 102.5zM359 629q-89 0 -151 -74.5t-62 -208.5q0 -141 69 -233t175 -92q90 0 150.5 74t60.5 211q0 152 -69 237.5t-173 85.5z" /></g><g transform="matrix(.012,-0,0,-.012,26.125,15.613)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g></svg> Nanocomposite Materials

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Chief Editor Stefano Bellucci is Professor of Theoretical Physics at the National Institute for Nuclear Physics in Frascati, Italy. His research interests include&nbsp;nanoscience and nanotechnology, nanocarbon-based composites, and the biomedical applications of nanomaterials.

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Journal of Nanomaterials

Nanoporous and Nanostructured Materials for Catalysis, Sensor, and Gas Separation Applications

Nanoporous and Nanostructured Materials for Catalysis, Sensor, and Gas Separation Applications

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