Journal Archive

Platinum Metals Rev., 2006, 50, (2), 103
doi: 10.1595/147106706X113878

Nitrous Oxide Greenhouse Gas Abatement Catalyst

  • Trine Kopperud
  • Catalysts,
  • Yara International, Porsgrunn, Norway

Among the naturally occurring greenhouse gases, nitrous oxide (N2O) is estimated to absorb 310 times (1, 2) more heat per molecule than carbon dioxide, thus contributing substantially to global warming (3). Atmospheric N2O is estimated to have increased by ∼ 16% since the Industrial Revolution and has contributed 4 to 6% to enhancing the greenhouse effect. Up to 40% of total atmospheric N2O is estimated to be man-made – equivalent to around 15 million tonnes per year of the gas (4). N2O is gradually accumulating in the atmosphere (2), despite slow breakdown by sunlight.

To reduce the production/emission of N2O as a waste product from nitric acid plants, the Norwegian nitrogen fertiliser manufacturer Yara International ASA has developed a N2O abatement catalyst (5), based on the reaction:


2N2O → 2N2 + O2


The de-N2O catalyst, which can cope with the high temperatures and corrosive environment of a nitric acid plant, is placed under the rhodium-platinum gauze pack and the catchment gauzes (6). It enables the N2O output from a plant to be reduced by 80% or more. The catalyst is of pelleted configuration, and when used with the Pt-Rh catalyst system gives an environmentally-enhanced process with highly efficient N2O abatement. The catalyst is installed in several nitric acid plants, and more are planned. Johnson Matthey, as a catalyst gauze supplier to nitric acid and caprolactam plants, will market the catalyst.

By using this new technology, N2O emission reductions can be brought into line with requirements sought by the Kyoto Protocol (7). T. KOPPERUD


  1.  “Global Warming Potentials”, Greenhouse Gas Inventory Data,
  2.  “Data by gas – N2O without LULUCF”,
  3.  “Greenhouse Gas Emissions”, Atmos., Climate & Environ. Info. Programme, Manchester Metro. Univ.,
  4.  U.S. EPA, “Nitrous oxide”,
  5.  Yara,
  6.  B. T. Horner, Platinum Metals Rev., 1993, 37, (2), 76
  7.  B. T. Horner, Platinum Metals Rev., 1991, 35, (2), 58
  8.  K. G. Gough and B. L. Wibberley, Platinum Metals Rev., 1986, 30, (4), 168
  9.  A. E. Heywood, Platinum Metals Rev., 1982, 26, (1), 28
  10.  UN Framework Convention on Climate Change, “The Mechanisms under the Kyoto Protocol: Joint Implemen., the Clean Dev. Mechan. and Emissions Trading”,

Supplementary Information

If you require more information regarding this process for the pursuit of nitrous oxide abatement projects, please contact:

Trevor Gillinder, Sales & Marketing Director, Johnson Matthey PLC Noble Metals, Tel: +44 (0)1763 253856, E-mail:, or

Garry Crooks, Sales & Marketing Manager, Johnson Matthey PLC Noble Metals, Tel: +44 (0)1763 253656, E-mail:


The Author

Trine Kopperud is the Section Manager, Catalysts, at Yara International in Porsgrunn, Norway. E-mail:

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