Erzeugung von kolloiden Übergangsmetallen in organischer Phase und ihre Anwendung in der Katalyse

Abstract

Durch Reduktion von Metallsalzen mit Tetraalkylammoniumhydrotriorganoboraten in organischer Phase können Metallkolloide der Elemente der Gruppen 6‐11 erhalten werden. Auf Trägeroberflächen adsorbiert sind diese Metallkolloide hochwirksame Hydrierkatalysatoren, deren Aktivität sich noch durch Dotierung mit niedervalenten Organotitanverbindungen steigern läßt.

Particle size effect of carbon-supported platinum catalysts for the electrooxidation of methanol

“…Colloidal Pt on a carbon support (carbon as received or oxidized) was prepared for us by B6nnemann et al [18] PtCI 2 is suspended in THF and reduced with (N(octyl)4BEt3H), where the ammonium salt functions as a stabilizer for the colloidal metal particles.…”

Preparation of supported PtRu/C electrocatalyst for direct methanol fuel cells

“…Great efforts have been made to explore suitable synthetic routes by many investigators. Petrow and Allen [8], Watanabe and Saegusa [9], and Bönnemann et al [10] developed colloidal deposition routes to prepare Pt electrocatalysts with high metal surface areas. Lasch et al [11] obtained highly active unsupported Pt and PtRu alloy electrocatalysts by a modified Adams method.…”

An SiO2-Embedded Nanoscopic Pd/Au Alloy Colloid

“…[10,13] Pre-prepared colloidal alloy particles, covered by various protecting shells, offer a different means of access to highly dispersed bimetallic catalyst precursors. [14][15][16][17][18][19] Following the so called ''precursor concept'', [20] these pre-prepared nanometals, for which the particle size distribution, composition and structure are rather well defined, may be deposited on 819 distribution. The physical characterisation by a combination of several techniques has shown that the SiO 2 -embedded Pd/ Au colloid preserves the size and the structural characteristics of the colloidal metal precursor.…”

“…[18][19][20][21] Here we report the preparation of a heterogeneous Pd/Au catalyst formed by the embedding of preprepared tetraalkylammonium-stabilized Pd/Au alloy particles in a solid SiO 2 matrix following a modified sol-gel process.…”

“…Monometallic Pd and Au colloids were prepared for comparison applying an analogous procedure. [19] The embedding of the Pd/Au colloid was carried out with tetraethoxysilicate (TEOS) as the precursor for the silica support. However, since the NR 4 -stabilized Pd/Au colloids are completely insoluble and even decompose at elevated temperatures in alcoholic solutions, the normal sol-gel procedure has to be modified by using THF as the solvent.…”