Influence of chlorine and metal cation impurities in the CO hydrogenation over Pd/SiO2 and Rh/SiO2

✍ Scribed by A.P. Gloor; R. Prins

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 770 KB
• Volume: 113
• Category: Article
• ISSN: 0165-0513
• DOI: 10.1002/recl.19941131013

✦ Synopsis

Abstract

Catalysts were prepared from ultra pure SiO~2~, Pd and Rh nitrates and chlorides, and by doping with Al, Fe, Na, K or Ca nitrate. The activities and selectivities of the Pd and Rh catalysts were investigated in CO hydrogenation at 553K, H~2~/CO = 2 or 3, and 2.5 or 4 MPa, respectively. Both the additives and the noble‐metal anions had a strong influence on the catalytic properties, even when no anions were present after catalyst preparation. These influences are due to dissolution of the metal additives by the aqueous noble‐metal salt solution during catalyst preparation, so that after reduction the additives end up in the vicinity of the metal particles. Chloride solutions extract the additives better from the catalyst support surface than nitrate solutions and therefore have a stronger influence on the catalytic properties, especially of SiO~2~‐supported catalysts.