NH₃ selective catalytic reduction of NO: A large surface TiO₂ support and its promotion of V₂O₅ dispersion on the prepared catalyst

A titania support with a large surface area was developed, which has a BET surface area of 380.5 m²/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt% vanadia. A special heat treatment was used in the calcination to maintain the large surface area and high dispersion of vanadium species. This catalyst was compared to a common V₂O₅-TiO₂ catalyst with the same vanadia loading prepared by a traditional method. The new catalyst has a surface area of 117.7 m²/g, which was 38% higher than the traditional V₂O₅-TiO₂ catalyst. The selective catalytic reduction (SCR) performance demonstrated that the new catalyst had a wider temperature window and better N₂ selectivity compared to the traditional one. The NO conversion was >80% from 200 to 450 °C. The temperature window was 100 °C wider than the traditional catalyst. Raman spectra indicated that the vanadium species formed more V-O-V linkages on the catalyst prepared by the traditional method. The amount of V-O-Ti and V=O was larger for the new catalyst. Temperature programmed desorption of NH₃, temperature programmed reduction by H₂ and X-ray photoelectron spectroscopy results showed that its redox ability and total acidity were enhanced. The results are helpful for developing a more efficient SCR catalyst for the removal of NO_x in flue gases.