oa The Behaviour of Platinum Catalysts for Ammonia Oxidation

Continuous observations by controlled atmosphere microscopy of the effects of heating platinum and rhodium-platinum alloy wires in ammonia-air mixtures indicated that attack on the wire surfaces predominates at the grain boundaries. The alloy wires, including used commercial catalyst gauzes, exhibited the formation of mobile promontories preceding the formation of angular crystalline platelets, whereas pure platinum wires did not show so much promontory growth, even at higher temperatures.