THE POSITIVE EFFECT OF HYDROGEN ON THE REACTION OF NITRIC-OXIDE WITH CARBON-MONOXIDE OVER PLATINUM AND RHODIUM CATALYSTS

Citation
R. Dumpelmann et al., THE POSITIVE EFFECT OF HYDROGEN ON THE REACTION OF NITRIC-OXIDE WITH CARBON-MONOXIDE OVER PLATINUM AND RHODIUM CATALYSTS, Catalysis letters, 32(3-4), 1995, pp. 357-369
Citations number
39
Categorie Soggetti
Chemistry Physical
Journal title
ISSN journal
1011372X
Volume
32
Issue
3-4
Year of publication
1995
Pages
357 - 369
Database
ISI
SICI code
1011-372X(1995)32:3-4<357:TPEOHO>2.0.ZU;2-4
Abstract
The effect of adding 330-4930 ppm hydrogen to a reaction mixture of NO and CO (2000 ppm each) over platinum and rhodium catalysts has been i nvestigated at temperatures around 200-250 degrees C. Hydrogen causes large increases in the conversion of NO and, surprisingly, also of CO. Oxygen atoms from the additional NO converted are eventually combined with CO to give CO2 rather than react with hydrogen to form water. Th is reaction is described by CO + NO + 3/2H(2)-->CO2 + NH3 and accounts for 50-100% of the CO2 formed with Pt/Al2O3 and 20-50% with Rh/Al2O3. With the latter catalyst a substantial amount of NO converted produce s nitrous oxide. Comparison with a known study of unsupported noble me tals suggests that isocyanic acid (HNCO) might be an important interme diate in a reaction system with NO, CO and H-2 present.