Abstract: The invention concerns a method for preparing supported nanoparticles comprising the following steps: introducing in an adequate solvent a metallic co-ordination complex capable of being decomposed at a temperature less than 200° C, optionally in the presence of a gas reactive under reactive gas pressure less than 3 bars; spraying the resulting preparation in conditions avoiding its decomposition in a fluidised bed containing suspended porous support grains, then breaking down the metallic co-ordination complex optionally in the presence of a reactive gas.

Abstract: A method of forming a metal colloid comprising a plurality of particles, each particle comprising a core of a metal, is described. The method comprises the steps of providing an organometallic precursor comprising the metal, combining the organometallic precursor and a solvent, which comprises water molecules, heating the combination of organometallic precursor and solvent so that the organometallic precursor decomposes to form a solution including the metal colloid and by-products, and removing the by-products to provide the metal colloid.