High-throughput syntheses of nano-scaled mixed metal sulphides

The use of metal and mixed metal sulphides as heterogeneous catalysts is often hampered by an undefined composition formed by in situ sulphidation of oxides. Controlled synthesis methods are serial and thus slow, because high-throughput (HT) methods for the well-directed syntheses of exactly defined metal sulphides and especially mixed metal sulphides are still lacking. The present contribution presents the development of HT synthesis methods for a broad range of nano-scaled sulphides for various applications, such as heterogeneous catalysts or photocatalysts. The nano-scale regime for the particle sizes offers the possibilities of high surface area, appearance of quantum size effects and the possibility of modification of their properties as well as stabilisation of the particles by surface coating. Several precursor molecules have been tested, which hydrolyse under specific conditions and release sulphide ions for metal and mixed metal sulphide precipitation. Particle size confinement was achieved by w/o microemulsions using non-ionic surfactants. In a first step for the parallel synthesis of sulphides a 9-fold reactor assembly was developed, which offers the possibility of synthesis by precipitation and separation of the resulting materials by filtration in one setup.