Formation of a novel type of reverse microemulsion system and its application in synthesis of the nanostructured La0.95Ba0.05MnAl11O19 catalystElectronic supplementary information (ESI) available: Table 1, Figs. 1b, 5, 6 and 7. See http://www.rsc.org/suppdata/cc/b4/b404133j/

Hexaaluminates: a review of the structure, synthesis and catalytic performance

The structure and catalytic applications of hexaaluminates.

Unique Layered Double Hydroxide Morphologies Using Reverse Microemulsion Synthesis

We report the first controlled synthesis of a layered double hydroxide (LDH) in a water-in-oil reverse microemulsion system. This synthesis of Mg2Al-LDHs was carried out in the reverse microemulsion of NaDDS (sodium dodecyl sulfate)-water-isooctane with water/surfactant molar ratio = 24. This enables us to obtain nanometer sized LDH platelets typically with a 40-50 nm diameter and 10 nm thickness. Further modification of the reverse microemulsion using triblock copolymers during crystallization allowed us to express different growth orientations of the LDH structure. These data show that the aspect ratio of LDHs can be flexibly adjusted over a wide range.

Engineering high-temperature stable nanocomposite materials

The low thermal stability of nanoparticles typically restricts their use in catalytic and other applications to low- to moderate-temperature conditions. We present a novel approach to the stabilization of nanosized noble metal particles by embedding them in a high-temperature stabilized hexa-aluminate matrix. The simple 'one-pot' approach is based on a microemulsion-templated sol-gel synthesis and yields mesoporous nanocomposite materials with pure textural porosity and excellent high-temperature stability up to about 1200 °C. To our knowledge, this is the first time that metal nanoparticles have been stabilized to such high temperatures. We furthermore find that the microemulsion templating allows a tailoring of the ceramic matrix without influencing the size of the embedded Pt particle. This opens up the possibility of a true multiscale engineering of nanocomposite materials. We see these novel materials therefore not only as very promising candidates for a broad range of high-temperature catalytic applications, but generally view this versatile synthesis route as a first step towards expanding the parameter range for nanoparticle applications.