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

• , the Au particles are homogenously distributed in the TiO2 film, with a broad particle-size distribution ranging from 0.25 to 6–8 nm. On the O350 calcined catalyst film, before CO oxidation, the maximum of the particle-size distribution is located close to ~2.0 (mean particle size 2.0 ± 1.6 nm, Figure

• conventional bright-field TEM mode with much lower sensitivity and spatial resolution than obtained on the present instrument (FEI Titan). On the former instrument, the smallest Au particles that could be detected within the background of the porous matrix were around 1.2 nm in diameter. In the current

• modulation). Possible reasons for the deactivation of TiO2 supported Au catalysts are the agglomeration/sintering of Au particles (“irreversible deactivation”) and the accumulation of stable adsorbed species, such as surface carbonates or water, on the catalyst surface [23][24][38][45][46]. The latter

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

• thickness had to be adjusted in a certain thickness-window in order to achieve the precise 2D particle arrays. Keywords: Au particles; dewetting; nanoimprint lithography; nanoparticle array; Introduction An increasing amount of scientific attention is being paid to the ordered arrangement of metallic

• substrate A have a spatial period of 513 nm and a depth of 150 nm. The holes in the substrate B have the same spatial period of 513 nm, a diameter of about 490 nm, and a depth of 120 nm. Figure 2 shows the SEM images of the Au particles formed from the 5 nm and 60 nm thick Au films on a flat SiO2/Si

• of particle size distribution σp increase with increasing film thickness. Figure 3 shows the SEM images of the Au particles produced from the 10 nm, 20 nm, 40 nm, and 60 nm thick Au films on the substrate A (pyramidal pits). For the 10 nm thick film, several particles could be observed in any one pit

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

• deposited onto a silicon wafer. (a) Ordered organization as described in the Experimental section, (b) random distribution. Frame sizes: 3 µm and 1 µm, respectively. As-synthesized Au particles on silicon in ultra-high vacuum. Frame size: 3 µm. AFM image of nanopatterned surface exhibiting Si pits: Frame

• the environmental conditions, manipulation of nanoparticles on a surface requires that they are loosely attached in order to be able to move them. The decrease of relative humidity from 53 down to 33% has a strong impact on the mobility of the hydrophilic Au NPs. Above RH = 43%, the adsorbed Au

• particles do not move, because the energy transferred from the tip to the particle during the tap is not high enough to break the capillary bridges formed at both interfaces. As a consequence, the overall energy does not reach the threshold barrier to move the particle and is completely dissipated in the