Mono-and bimetallic colloidal particles have gained increasing attention in science and application throughout the last several years. In this contribution, we present a synopsis of the wet chemical syntheses of these materials and survey po- [a] 2455 tential applications in catalysis and materials science. Methods for the characterization of these particles and their surfaces are not reviewed here.potential of nanostructured metal colloids as fuel cell catalysts. [17Ϫ20] Eur.

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Magnetic, highly porous ordered carbon of the CMK‐3 and CMK‐5 type and with pure carbon or carbon–nitrogen framework were nanoengineered by a sequence of bulk manipulation steps. The materials can be used as efficient magnetic adsorbents (see picture) or catalysts, but applications going far beyond these can be envisaged.

The electrocatalytic activity of a bimetallic Pt0.5Ru0.5N(Oct4)Cl colloid toward the oxidation of CO and a CO/H2 gas mixture (simulated reformer gas) was measured. The particle size distribution with a mean diameter of 1.7 ± 0.5 nm was determined by high-resolution transmission electron microscopy, and the formation of stoichiometrically alloyed particles was verified by point-resolved energy dispersive X-ray analysis. The CO-stripping voltammetry of glassy carbon supported Pt0.5Ru0.5 clusters was found to be in excellent agreement with CO-stripping voltammetry data measured on well-characterized bulk alloy electrodes. The activity of the colloid toward the continuous oxidation of 2% CO in H2 was assessed in a rotating disk electrode configuration at 25 °C in 0.5 M H2SO4, leading to the conclusion that PtRu colloids are a promising route toward the preparation of bimetallic high-surface-area fuel cell catalysts.

Reduction of metal salts with tetraalkylammonium hydrotriorganoborates in organic phases yields a very narrow size range of metal colloids of the elements of groups 6–11. Adsorbed on carrier surfaces, these colloids are highly active hydrogenation catalysts whose activity can be further increased by doping with low‐valent organotitanium compounds.