TiO₂-carbon nanotubes composite supported MnOx-CuO catalyst for low-temperature NH₃-SCR of NO: Investigation of SO₂ and H₂O tolerance

A series of titania-carbon nanotubes (TiO2-CNTs) supported MnOx-CuO catalysts were prepared and investigated for NH3-SCR of NO at low temperature. It was observed that the addition of Cu and/or CNTs to Mn/TiO2 has a beneficial effect in improving the activity of the catalyst. In addition, the effect of Cu loading was also studied and found that the catalyst with 5 wt% Cu (Mn-Cu-5/Ti-CNTs) exhibited the best NH3-SCR performance. Remarkably, the Mn-Cu-5/Ti-CNTs showed excellent resistance to SO2/H2O in comparison to the Mn/TiO2 catalyst. The addition of CNTs has increased the specific surface area, total pore volume, and reduced the average pore size of the catalyst. Meanwhile, the Cu loading has enhanced the Mn4+ species and chemisorbed oxygen species on the surface of the catalyst. Besides, the incorporation of both Cu and CNTs have decreased the catalyst reduction temperature and increased the amount and strength of acidic sites on the catalyst. All these factors contributed to the superior NH3-SCR activity and SO2/H2O resistance of the catalyst.