Characterization and activity of copper-on-carbon catalysts for low-temperature selective reduction of nitric oxide with ammonia

The activities for NO reduction with ammonia in the presence and absence of O₂ have been examined over copper salts supported on activated carbon (AC) and carbon black (CB) which have been characterized by application of X-ray diffraction and scanning electron microscopy before and after use in the reduction process. The beneficial effects of increases in loading and the introduction of oxygen are demonstrated. On the most active catalyst and under optimum conditions 100% reduction of the NO to N₂ occurs at 180 °C and Cu, Cu₂O and CuO on the catalyst are shown to be present at various stages of the preparation and reduction process with large crystallites of metallic copper detected on the AC catalyst of optimum loading. Deactivation and regeneration of the catalysts is also examined. A mechanism for the redox process is proposed. This revised version was published online in July 2006 with corrections to the Cover Date.