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

• transmission electron microscopy images and XRD results characterizing the structure and morphology of these films and the distribution and particle size of the Au nanoparticles. The chemical state of the materials was characterized by XPS, and finally the catalytic activity of these model systems was

Formation of precise 2D Au particle arrays via thermally induced dewetting on pre-patterned substrates

• Dong Wang,
• Ran Ji and
• Peter Schaaf

Beilstein J. Nanotechnol. 2011, 2, 318–326, doi:10.3762/bjnano.2.37

• nanostructuring. The synthesis of 3D arrays of ligand stabilized Au nanoparticles using the self-assembly method has been reported [7], and electron beam lithography has also been used to define positioned nanoparticles at low throughput [8]. Another simple method for the formation of nanoparticle arrays is based

Manipulation of gold colloidal nanoparticles with atomic force microscopy in dynamic mode: influence of particle–substrate chemistry and morphology, and of operating conditions

• Samer Darwich,
• Karine Mougin,
• Akshata Rao,
• Enrico Gnecco,
• Shrisudersan Jayaraman and
• Hamidou Haidara

Beilstein J. Nanotechnol. 2011, 2, 85–98, doi:10.3762/bjnano.2.10

• the effect of functional (hydrophilic vs hydrophobic) molecules grafted on the Au nanoparticles on their mobility. In addition, we will address the important issue of environmental conditions (T, RH%), surface topography and tip scan velocities on the manipulation performance of gold nanoparticles

• often heterogeneous in their chemical composition, functionalized nanoparticles provide good model systems to study and tune the mobility of nano-objects on these substrates. As a next step, the role of the hydrohilicity and hydrophobicity of the functional grafting on spherical Au nanoparticles is

• from capillary bridges has also a strong influence on the mobility of spherical Au nanoparticles during their manipulation. Indeed, capillary forces of water films between both interfaces, nanoparticle–surface and tip–nanoparticle, will depend on the volume of liquid condensate present at the interface