Promotional effects of copper doping on Ti-Ce-O_x for selective catalytic reduction of NO by NH₃ at low temperature

A series of copper-doped Ti-Ce-O_x complex oxide catalysts were synthesized by sol-gel method and evaluated for selective catalytic reduction of NO by NH₃ at low temperature. The promotional effect of copper doping on their structure, acidity and catalytic activity were investigated by means of Brumauer-Emmett-Teller (BET), temperature-programmed reduction (H₂-TPR), X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed desorption (NH₃-TPD) and pyridine adsorption infrared spectrum (Py-IR) technologies. Results showed that the copper additives could improve the low temperature catalytic performance for selective catalytic reduction of Ti-Ce-O_x catalyst and the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached above 90% at 150-250 °C (Ti/Cu=4). The introduction of copper could enhance the redox property of the Ti-Ce-O_x complex oxide catalyst, refine the particle size caused by lattice distortion and oxygen vacancy defect and enhance the acid amount of the Lewis acid site. Moreover, Ti-Cu-Ce-O_x complex oxide catalyst also had good anti-sulfur ability and anti-water influence, when injecting 300 ppm SO₂ and 10 vol.%H₂O, the NO conversion efficiency of Ti-Cu-Ce-O_x catalyst reached 80%.