Ordered, mesoporous cobalt oxide was synthesized via a nanocasting pathway from organically modified large‐pore Ia3d silica. A replica structure could be obtained, which shows weak magnetic ordering ...at low temperatures due to the small size of the individual Co3O4 domains forming the mesostructure.
Ordered mesoporous carbon, named as NCC‐1, has been synthesized via a nanocasting process using SBA‐15 as the template and diluted furfuryl alcohol solution as the carbon source. NCC‐1 shows a ...bimodal pore size distribution (see Figure) in the mesopore range and a high pore volume up to 3.2 cm3 g–1. Since the pore systems are independently generated at different stages during the synthesis, they can also be modified independently.
The mesopores in silica fibers run in a circular direction around the axis(see Figure), as demonstrated here by examining the optical properties and electron microscopy images of mesoporous silica ...fibers grown by slow acid synthesis. These fibers are a unique example of a material that is highly ordered on the nanometer scale, but where the ordering does not lead to translational invariance in all three dimensions.
FTIR spectroscopy in transmission mode combined with a focal plane array (FPA) detector was employed for parallel characterization of Pt-containing zeolites ZSM-5 and Y. The different Pt species in ...the zeolite were investigated using the chemisorption of carbon monoxide. With the new transmission setup, 8-fold degree of parallelization was achieved. This significantly lowered the total time required for collection of the desired information from a set of samples. The optical setup based on FPA-IR detection provides data of high reliability. For the discussion of the individual IR band assignment, TEM analysis data are included to corroborate the conclusions.
In this study, a degradable, hierarchically porous silica/apatite composite material is developed from a simple low-temperature synthesis. Mesoporosity is induced in the silica portion by the use of ...supramolecular templating. The template is further removed by calcination. Firstly, hydroxyapatite is synthesized through a sol–gel method at near room temperature conditions. After the mineralization process, the crystal surface is coated with a mesoporous silica matrix using the templates already present in the bulk solution. The material is characterized by XRD, N
2-sorption, FT–IR, SEM/EDS, and TEM. The coating layer is distributed fairly homogeneously over the apatite surface and the coating thickness is easily adjustable and dependent on the amount of added silica precursor. The hybrid material is shown to efficiently induce calcium phosphate formation under in vitro conditions and simultaneously work as a carrier system for drugs.
In this study, we present a synthetic pathway for the fabrication of self-supporting zeolite monoliths consisting of crystallized nanoparticles. A resorcinol-formaldehyde-based organic aerogel is ...used as a template, and silicalite-1 is used as the zeolite example. The silicalite-1 monoliths obtained consist of individual well-defined zeolite nanocrystals with sizes of 30-40 nm. The monoliths exhibit a high mechanical stability and have hierarchical porosity, with micropores within the zeolite particles, a mesopore system formed by the packing of the nanoparticles, and a macropore system on the monolith level. Such monolithic zeolites show high selectivity typically above 80% to epsilon-caprolactam combined with a high rate of reaction of 0.46 g(caprolactame)/(g(catalyst).h) in the Beckmann rearrangement of cyclohexanone oxime.
By using laser-induced heating, we prepared Au-Ag nanoalloys via three different procedures: (i) mixture of Au nanoparticles and Ag(+) ions irradiated by a 532 nm laser, (ii) mixture of Au and Ag ...nanoparticles irradiated by a 532 nm laser, and (iii) mixture of Au and Ag nanoparticles irradiated by a 355 nm laser. Procedure i is advantageous for the production of spherical alloy nanoparticles; in procedures ii and iii, nanoalloys with a sintered structure have been obtained. The morphology of the obtained nanoalloys depends not only on the laser wavelength but also on the concentration of nanoparticles in the initial mixture. When the total concentration of Ag and Au nanoparticles in the mixture is increased, large-scale interlinked networks have been observed upon laser irradiation. It is expected that this selective heating strategy can be extended to prepare other bi- or multi-metallic nanoalloys.
Results from aromatic aminations and Kumada couplings, together with spectroscopic analyses (TEM, EDX, ICP-AES, React-IR), reveal that catalysis using nickel-on-charcoal (Ni/C) is most likely of a ...homogeneous rather than heterogeneous nature. In the course of a reaction with Ni/C, nickel bleed from the support was calculated to be as high as 78%. However, the existence of an equilibrium for this homogeneous species between nickel located inside vs outside the pore system of charcoal strongly favors the former, thus leaving only traces of metal detectable in solution. This accounts for virtually complete recovery of nickel on the charcoal following filtration of a reaction mixture and allows for recycling of the catalyst. TEM and EDX data were used to explain different reactivity profiles of Ni/C, which depended upon the method of reduction used to convert Ni(II)/C to Ni(0) as well as the level of nickel loading on the support.
