Editing Ostwald process (section)

==== Platinum-rhodium catalyst ====
The platinum and rhodium catalyst is frequently replaced due to decomposition as a result of the extreme conditions which it operates under, leading to a form of degradation called [[cauliflowering]].<ref name=":02">{{Cite journal |last1=Hannevold |first1=Lenka |last2=Nilsen |first2=Ola |last3=Kjekshus |first3=Arne |last4=Fjellvåg |first4=Helmer |date=2005-04-28 |title=Reconstruction of platinum–rhodium catalysts during oxidation of ammonia |url=https://www.sciencedirect.com/science/article/pii/S0926860X05000669 |journal=Applied Catalysis A: General |volume=284 |issue=1 |pages=163–176 |doi=10.1016/j.apcata.2005.01.033 |bibcode=2005AppCA.284..163H |issn=0926-860X|url-access=subscription }}</ref> The exact mechanism of this process is unknown, the main theories being physical degradation by hydrogen atoms penetrating the platinum-rhodium lattice, or by metal atom transport from the centre of the metal to the surface.<ref name=":02" />