Isocyanate formation in the catalytic reaction of CO + NO on Pd(111): an in situ infrared spectroscopic study at elevated pressures

J Am Chem Soc. 2002 Jul 24;124(29):8524-5. doi: 10.1021/ja020571m.

Abstract

The catalytic CO + NO reaction to form CO2, N2, and N2O has been studied on a Pd(111) surface at pressures up to 240 mbar using in situ polarization modulation infrared reflection absorption spectroscopy (PM-IRAS). At 240 mbar, for a pressure ratio of PCO:PNO = 3:2 and under reaction conditions, besides adsorbed CO, the formation of isocyanate (-NCO) was observed. Once produced at 500-625 K, the isocyanate species was stable within the entire temperature range studied (300-625 K). On the other hand, its formation required a total CO + NO pressure of at least 0.6 mbar, illustrating the importance of in situ infrared experiments under high-pressure conditions. The significance of the isocyanate formation for the CO + NO reaction on Pd(111) is discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Air Pollutants / chemistry*
  • Carbon Dioxide / chemistry
  • Carbon Monoxide / chemistry*
  • Isocyanates / chemistry*
  • Nitric Oxide / chemistry*
  • Nitrogen / chemistry
  • Nitrogen Dioxide / chemistry
  • Palladium / chemistry*
  • Pressure
  • Radioisotopes / chemistry*
  • Spectrophotometry, Infrared / methods
  • Vehicle Emissions

Substances

  • Air Pollutants
  • Isocyanates
  • Radioisotopes
  • Vehicle Emissions
  • Carbon Dioxide
  • Nitric Oxide
  • Palladium
  • Carbon Monoxide
  • Nitrogen
  • Nitrogen Dioxide