Revisiting Ammonia Oxidation Reaction on Polycrystalline Pt: A Rotating Ring Disk Electrode-Based Investigation

Ammonia oxidation on polycrystalline platinum disk and platinum-black catalysts was investigated in alkaline electrolyte using a rotating ring-disk electrode. The study examines how electrode porosity, ammonia concentration, mass transport, and potential limits affect the reaction and catalyst poisoning. Increasing the ammonia concentration from 1.0 mM to 1.0 M shifted the oxidation onset by approximately 60-70 mV and the hydrogen adsorption/desorption peaks at Pt {100} sites by approximately 130 mV. The results also show that unintentional dissolved oxygen can contribute to features in voltammetry and chronoamperometry.