Vanadium Substitution as an Effective Way to Enhance the Redox Ability of Tungstophosphoric Acid and for Application of NH3-SCR

A novel TiO2-supported vanadium-substituted tungstophosphoric acid (PW11V/TiO2) catalyst was designed and applied for selective catalytic reduction of NOx by NH3. Compared with the commercial tungstophosphoric acid (PW12/TiO2), PW11V/TiO2 displayed a nearly 90% activity improvement at 300 °C. In addition, the favorable resistance and stability to SO2 were also obtained over PW11V/TiO2 catalyst. Phase analysis and spectroscopy results indicated the vanadium was successfully incorporated into the molecular structure of PW12, and the Keggin framework still keep stable over the TiO2 support. H2-TPR test proved the incorporation of vanadium promoted the redox ability of PW11V. The present study provides us an effective way to improve the performance of catalytic removal of NOx through tungstophosphoric acid catalyst. After introduction of V species, the obtained PW11V/TiO2 catalyst show better NH3-SCR performance and N2 selectivity than PW12/TiO2 catalyst.