Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

• Yaron Paz

Beilstein J. Nanotechnol. 2011, 2, 845–861, doi:10.3762/bjnano.2.94

Synthesis and catalytic applications of combined zeolitic/mesoporous materials

• Jarian Vernimmen,
• Vera Meynen and
• Pegie Cool

Beilstein J. Nanotechnol. 2011, 2, 785–801, doi:10.3762/bjnano.2.87

• mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i) the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii) the remarkable stability, catalytic activity and

• selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials. Focus is put on the synthesis and the applications of the combined zeolitic/mesoporous materials. The different synthesis approaches and formation mechanisms leading to these

• materials are comprehensively discussed and compared. Moreover, Ti-containing nanoporous materials as redox catalysts are discussed to illustrate a potential implementation of combined zeolitic/mesoporous materials. Keywords: catalysis; characterization; combined zeolitic/mesoporous materials; synthesis

Micro- and mesoporous solids: From science to application

• Jörg J. Schneider

Beilstein J. Nanotechnol. 2011, 2, 774–775, doi:10.3762/bjnano.2.85

• decades especially, mesoporous materials having pore dimensions between 2 and approximately 50 nm have emerged, and this group has established itself as an important class of solid-state materials with a huge and still constantly growing number of new congeners with pores on the nano- to mesoscale. These

• can be broadly classified into inorganic, organic and metal–organic types. Nevertheless, hybrids of these compositions have even been realized, extending the diversity in the chemical composition of such mesoporous solids further still. Besides their different chemical composition, the pore morphology

• , geometry and pore dimensions make these materials outstanding with respect to, e.g., catalytic reaction processes, in the area of sensorics, photonics and gas storage (Figure 1). In the realm of gas storage, mesoporous metal–organic frameworks (MOFs) appeared on the scene a couple of years ago and have

Nanostructured, mesoporous Au/TiO₂ model catalysts – structure, stability and catalytic properties

• Matthias Roos,
• Dominique Böcking,
• Kwabena Offeh Gyimah,
• Gabriela Kucerova,
• Joachim Bansmann,
• Johannes Biskupek,
• Ute Kaiser,
• Nicola Hüsing and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 593–606, doi:10.3762/bjnano.2.63

• model catalysts consisting of a thin mesoporous TiO2 film of 200–400 nm thickness with Au nanoparticles, with a mean particle size of ~2 nm diameter, homogeneously distributed therein. The systems were prepared by spin-coating of a mesoporous TiO2 film from solutions of ethanolic titanium

• and catalytic properties of ultra-thin Au/TiO2 catalyst films, which were prepared by spin-coating a thin film of mesoporous TiO2 of 200–400 nm thickness on a flat Si(100) substrate and subsequent loading with Au nanoparticles. After describing the experimental procedures, we first present

• catalysts based on highly dispersed mesoporous TiO2 supports [33]. From the ICP–OES analysis of the Au/TiO2 catalyst material (cast in the Petri dishes) we derived a Au content of 2.7 wt %. This is in the range of Au contents typical for realistic supported Au catalysts [25][34]. XPS measurements of the

Inorganic–organic hybrid materials through post-synthesis modification: Impact of the treatment with azides on the mesopore structure

• Miriam Keppeler,
• Jürgen Holzbock,
• Johanna Akbarzadeh,
• Herwig Peterlik and
• Nicola Hüsing

Beilstein J. Nanotechnol. 2011, 2, 486–498, doi:10.3762/bjnano.2.52

• strong influence on the structure in the mesoporous regime, with changes such as an increase of mesopore diameter, pore volume and lattice constants, as well as a concomitant decrease of the pore wall thickness, as confirmed by small angle X-ray scattering, transmission electron microscopy, and nitrogen

• solvent (N,N-dimethylformamide, 1,1,3,3-tetramethylurea, 1,3-dimethyl-2-imidazolidinone) or a protic solvent that can form hydrogen bonds, such as water, was used. Keywords: inorganic–organic hybrid materials; mesoporous materials; nucleophilic substitution; silica; sol–gel chemistry; Introduction

• with selectivity provided by meso- or micropores. This is especially true for materials with uniform pore size distributions in the mesoporous (2–50 nm) and/or macroporous regime (>50 nm) [1][2][3]. A powerful tool in the preparation of stable, mesoscopically organized materials that are characterized

Novel acridone-modified MCM-41 type silica: Synthesis, characterization and fluorescence tuning

• Maximilian Hemgesberg,
• Gunder Dörr,
• Yvonne Schmitt,
• Andreas Seifert,
• Zhou Zhou,
• Robin Klupp Taylor,
• Sarah Bay,
• Stefan Ernst,
• Markus Gerhards,
• Thomas J. J. Müller and
• Werner R. Thiel

Beilstein J. Nanotechnol. 2011, 2, 284–292, doi:10.3762/bjnano.2.33

• Erlangern, Germany Heinrich-Heine-Universität Düsseldorf, Institut für Organische Chemie und Makromolekulare Chemie, Universitätsstraße 1, D-40225 Düsseldorf, Germany 10.3762/bjnano.2.33 Abstract A Mobil Composition of Matter (MCM)-41 type mesoporous silica material containing N-propylacridone groups has

• ; fluorescence; scandium; MCM-41; Introduction Mesoporous silicates are widely used for a variety of applications such as gas storage and heterogeneous catalysis, e.g., the synthesis of ε-caprolactam [1], or the decomposition of nitrous oxides [2]. MCM-41, MCM-48 and other silica materials can normally be

• determination of lanthanide salts in aqueous solution, the fluorescence undergoing a bathochromic shift directly correlated to the acidity of the cation bound to its carbonyl group [8]. We therefore sought to create a micro- or mesoporous material containing covalently bound acridone units that would serve the

Schottky junction/ohmic contact behavior of a nanoporous TiO₂ thin film photoanode in contact with redox electrolyte solutions

• Masao Kaneko,
• Hirohito Ueno and
• Junichi Nemoto

Beilstein J. Nanotechnol. 2011, 2, 127–134, doi:10.3762/bjnano.2.15

• materials have promising capabilities applicable for the construction of various photonic and electronic devices. In this paper, a mesoporous TiO2 thin film photoanode was soaked in an aqueous methanol solution using an O2-reducing Pt-based cathode in contact with atmospheric air on the back side. It was

• shown from distinct photocurrents in the cyclic voltammogram (CV) that the nanosurface of the mesoporous n-TiO2 film forms a Schottky junction with water containing a strong electron donor such as methanol. Formation of a Schottky junction (liquid junction) was also proved by Mott–Schottky plots at the

• mesoporous TiO2 thin film photoanode, and the thickness of the space charge layer was estimated to be very thin, i.e., only 3.1 nm at −0.1 V vs Ag/AgCl. On the other hand, the presence of [Fe(CN)6]4− and the absence of methanol brought about ohmic contact behavior on the TiO2 film and exhibited reversible

Pore structure and surface area of silica SBA-15: influence of washing and scale-up

• Jörg P. Thielemann,
• Frank Girgsdies,
• Robert Schlögl and
• Christian Hess

Beilstein J. Nanotechnol. 2011, 2, 110–118, doi:10.3762/bjnano.2.13

• larger batch sizes the influence of the quantity of solvent on the quality of the SBA-15 is reduced. Keywords: SBA-15; scale-up; silica mesoporous material; tensile strength effect; washing; Introduction SBA-15 is a mesoporous silica sieve based on uniform hexagonal pores with a narrow pore size

• Å as compared to samples 2A and 2B. This behaviour shows that the order of the pores in sample 2C has decreased due to washing with increased solvent quantities. The ratio of the microporous to mesoporous surface area for 2C stays almost constant compared to 2A, whereas the contents of micropore

Synthesis of LiNbO₃ nanoparticles in a mesoporous matrix

• Anett Grigas and
• Stefan Kaskel

Beilstein J. Nanotechnol. 2011, 2, 28–33, doi:10.3762/bjnano.2.3

• impregnation from the metal precursor and mesoporous silica SBA-15 as the template. A rapid one-step treatment in an IR furnace reduces the preparation time to only 10 min. In comparison, a conventional furnace requires 5 h reaction time to produce nanoparticles with similar textural properties. Another

• ). The obtained nanoparticles are spherical with a diameter of approximately 10 nm. Keywords: LiNbO3; ordered mesoporous material; SBA-15; template synthesis; Introduction Lithium niobate is one of the most important ferroelectric materials. At room temperature it has a rhombohedral symmetry and space

• present work, we investigated a rapid and efficient one-step route for the direct IR-accelerated synthesis of LiNbO3 nanopowders using an ordered mesoporous silica SBA-15 as the template, in combination with an IR furnace for the crystallization. The matrix stabilizes the nanoparticles against sintering