Laan, Petrus C. M. Franke, Mareena C. van Lent, Richard Juurlink, Ludo B. F. Heterogeneous Catalytic Oxidation of Ammonia by Various Transition Metals A well-known demonstration is adapted to simplify the illustration of heterogeneous catalytic oxidation of ammonia. Various metal catalyst wires are placed above the liquid level in a flask containing concentrated ammonia. After brief preheating, some metal wires continue to glow, providing visual evidence of an overall exothermic reaction taking place at the catalyst surface. Thermal heating by a butane flame prior to insertion and <i>in situ</i> resistive heating using a power supply yield identical results. Active catalysts are the group 9 and 10 elements Rh, Ir, Pd, and Pt. Besides the illustration of the Sabatier principle, the effect of the ammonia-to-oxygen ratio can also be visualized, and active metals vary in the production of a grayish smoke. These observations provide a starting point to discuss catalytic selectivity, a topic of great relevance to industrial catalytic oxidation of ammonia. catalyst surface;power supply;butane flame;Sabatier principle;Various metal catalyst wires;Active catalysts;Various Transition Metals;Heterogeneous Catalytic Oxidation;oxidation;illustration;Thermal heating;10 elements Rh;metal wires;ammonia-to-oxygen ratio;grayish smoke;group 9 2019-07-31
    https://acs.figshare.com/articles/media/Heterogeneous_Catalytic_Oxidation_of_Ammonia_by_Various_Transition_Metals/9199097
10.1021/acs.jchemed.9b00351.s010