The Cu/TiO2 catalysts with different Cu loadings were prepared, and their performance in the selective catalytic oxidation of ammonia (SCO of NH3) was compared with 10% Cu/Al2O3. The 10% Cu/TiO2 has the best performance among its series for NH3 conversion and N-2 selectivity. At 250 degrees C, the 100% conversion of ammonia was achieved and the selectivity to N2 came to 95%. The 10% Cu/TiO2 catalyst has a much higher activity for the SCO of ammonia and a slightly lower N2 selectivity than 10% Cu/Al2O3 because of the higher oxygen mobility and lower oxygen bonding strength, which demonstrated that TiO2 is a more suitable support than Al2O3 for copper-based catalyst in the SCO of NH3. The mechanisms involved in the SCO of NH3 reaction on the 10% Cu/TiO2 catalyst have also been investigated using TPD, TPR as well as in situ DRIFTS methods. (c) 2007 Elsevier B.V. All rights reserved.