Surface Phenomena on Rhodium-Platinum Gauzes

The rare occurrence of inactive catalyst gauzes for no obvious reason has led to comparative studies of the structures of rhodium-platinum wires from both active and inactive gauzes. Active gauzes showed the regular development of octagonal crystal faces on the nodular growths on the wires. Inactive gauzes showed no crystal development and an amorphous growth appeared on the wires. Segregation of rhodium and iron at the surface occurred in this case, perhaps due to unusual plant operating conditions, and may have caused deactivation.