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 NOx in flue gases.

Graphical AbstractA better SCR catalyst was developed by specific method using a new large surface area titania support. The dispersion of vanadium species was promoted. The better dispersed vanadium species and the larger surface area improved the redox ability and acid sites of the catalyst. As a result, the newly developed catalyst showed better SCR performance and stability.Figure optionsDownload as PowerPoint slide