This paper reports a novel room-temperature ionic liquid (RTIL), [C4mim]+ BF4 -, as template to monolithic mesoporous silica with wormhole framework via a convenient nanocasting technique. In contrast with the applied liquid crystal self-assembly of long-chain surfactants on the preparation of mesoporous nanostructures, a new so-called hydrogen bond-co-π−π stack mechanism was proposed to be responsible for the present self-assembly of the RTIL in the reaction system for the formation of the wormlike mesopore, in which both the hydrogen bonds formed between the [BF4]- and silano group of silica gel and the π−π stack interaction of the neighboring imidazolium rings play crucial roles in the formation of the wormhole framework of mesporous silica. The proposed hydrogen bond-co-π−π stack mechanism with the RTIL as template may open a new pathway to prepare mesoporous materials.

Electrospun polymer fibers can be coated with amorphous titanium dioxide using a sol–gel coating technique. After removal of the organic material by thermal treatment hollow titania fibers are produced. The sol–gel coating is able to reproduce the finer details of the fiber, e.g., the Figure shows how oval nodules that were indentations on the initial polymer are mimicked in the final inorganic structure of the titania fibers (see also images on the front cover).

The formation of porous metal oxide networks using mixed titania/zirconia precursor solutions was achieved by a polymer gel templating technique. The inorganic porous materials result from a coating of the initial template with obvious structural similarities between the polymer gel and the final inorganic network. The mixed TiO2/ZrO2 network structures exhibit higher surface areas than a corresponding pure titania network, and in a certain range of metal oxide compositions X-ray amorphous mixed glasses are obtained upon calcination at 500 °C. The photocatalytic efficiencies of the TiO2 and TiO2/ZrO2 networks have been assessed by monitoring the photodecomposition of two organic molecules:  salicylic acid and 2-chlorophenol. The TiO2 network was found to exhibit an efficiency of ≈60% and ≈65% of the standard Degussa P25 TiO2 (of nanoparticulate morphology) for the salicylic acid and 2-chlorophenol reactions, respectively. For both photocatalytic reactions the presence of zirconia in the titania network (at a molar ratio of 1:9) resulted in enhanced photocatalytic activity relative to the pure TiO2 network (80% and 100% the efficiency of Degussa P25), which is believed to be due to a number of factors including an increased surface area and a decrease of the anatase to rutile crystal phase transformation. A further increase in the zirconia-to-titania ratio leads to decreased activity as amorphous materials are obtained and zirconia itself does not act as a photocatalyst under the experimental conditions used.

Abstract:Steam reforming of methanol for production of hydrogen can be carried out over copper based catalyst. In the work presented here, the catalytic properties of a CuO/ZrO 2 catalyst (8.5 wt%) synthesised by a templating technique were investigated with respect to activity, long term stability, CO formation, and response to oxygen addition to the feed. The results were obtained using a fixed bed reactor and compared to a commercial methanol synthesis catalyst CuO/ZnO/Al 2 O 3 . It is shown that, depending on the time on stream, the temporary addition of oxygen to the feed has a beneficial effect on the activity of the CuO/ZrO 2 catalyst. After activation, the CuO/ZrO 2 catalyst is found to be more active ( per copper mass) than the CuO/ZnO/Al 2 O 3 system, more stable during time on stream ( measured up to 250 h), and to produce less CO. Structural characterisation by means of X-ray powder diffraction (XRD) and X-ray absorption spectroscopy (XAS) reveals that the catalyst (as prepared) consists of crystalline, tetragonal zirconia with small domain sizes ( about 60 Angstrom) and small/disordered crystallites of CuO.

The infiltration of preformed nanoparticles in a porous polymer gel template for the formation of inorganic networks retaining high porosity is described. The use of a number of metal oxide sols including titania, zirconia, and indium oxide, and mixtures of TiO2/ZrO2 and TiO2/In2O3, resulted in structures that demonstrated templating of the initial organic gel. The final networks were homogeneously porous and had significant surface areas of up to 65 m2 g-1. The wall thickness of the inorganic structure and the surface area, along with the final amount of inorganic material that infiltrated the polymer gel, were found to be dependent on the metal oxide being considered. Photocatalytic studies of the titania-containing networks were monitored by the degradation of 2-chlorophenol and compared with the reference titania photocatalyst, Degussa P25. The titania network was about 20% more active than the standard and the mixed metal oxides showed higher activity again (up to 80% more active than the Degussa P25 sample). The addition of the second metal oxide to the titania decreased the amount of the rutile crystalline phase in the final structure and increased the network surface area, both of these changes are considered positive for enhancement of the photocatalytic activity.