Waste aqueous ammonia is produced in significant quantities as part of coke production processes required for steelmaking. In this work, the utilization of a simulated aqueous ammonia waste (ammonium hydroxide) was investigated using a commercially available anode-supported solid oxide cell. The electrical performance of the cell was characterized using I-V curves and the output gases from the anode were measured in real-time using quadrupole mass spectrometry. Upon delivery to the anode, there was total decomposition of ammonia to form hydrogen and nitrogen with no NO xformation observed. The cell operated more efficiently in fuel cell mode due to alleviation of OCV, activation, and concentration losses. In electrolysis mode, the cell produced H2through a mixture of catalytic ammonia decomposition (48 vol%) and electrochemical H2O reduction (52 vol%) to yield output gas mixtures composed of 90-93 vol% H2(voltage dependent) balanced only in N2.