Structural tuning and NH3-SCO performance optimization of CuO-Fe2O3 catalysts by impact of thermal treatment

CuO-Fe₂O₃ catalysts categorized by the thermal treatment were systematically investigated for ammonia oxidation to nitrogen. The activity results exhibited that the calcination temperature had a significant contribution to the difference of the catalytic performance. Lower calcination temperature (≤500 °C) resulted in the excellent catalytic activity owing to the formation of large surface area, superior redox behavior and abundant surface oxygen species. On the contrary, the catalytic activity of catalysts declined with further raising the calcination temperature (≥600 °C) due to the destroyed structure and acid sites. In addition to this, DRIFTS study revealed that the reaction of ammonia oxidation largely depended on the presence of surface active oxygen on the catalysts. In particular, fast ammonia activation was observed on CuO-Fe₂O₃–500 °C, which was reflected by the rapid formation of –NH₂ and nitrate species on DRIFTS combining the XPS results. The intermediates –NH₂ and NO of internal selective catalytic reduction (iSCR) predominantly accounted for the excellent catalytic activities.