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
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.