The reactions of Oz, NO, and soot from diesel exhaust over Cu containing catalysts can significantly reduce soot and NOx emissions while producing N-2 and CO2. We have evaluated the performance of Cu ion exchanged ZSM-5 and Cu adsorbed on granulated activated carbon (Cu-GAC) using GAC as a surrogate for soot in a packed bed reactor. CO, formed primarily by the oxidation of GAC with O-2, appears to be a stable intermediate in the reduction of NO. With experimental parameters chosen to simulate diesel exhaust conditions, Cu-GAC is more effective than GAC mixed with Cu-ZSM-5, converting six times more NOx to N-2 at 500 degreesC at the representative gas hourly space velocity of 50,000. Both catalysts art: poisoned by H2O and SO2. A mechanism is presented that is consistent with the experimental results.