Hydrothermally Stable WO3/ZrO2–Ce0.6Zr0.4O2 Catalyst for the Selective Catalytic Reduction of NO with NH3

A new catalyst WO3/ZrO2–Ce0.6Zr0.4O2 (15 wt % WO3/ZrO2:Ce0.6Zr0.4O2 = 50:50) has been developed for the selective catalytic reduction of NO with NH3. The redox component Ce0.6Zr0.4O2 was dispersed on the surface of acidic WO3/ZrO2 by the solution combustion method showing the best NOx reduction efficiency among the catalysts prepared by various modes of mixing of the components. The catalyst has been characterized by XRD, Raman spectroscopy and NH3-TPD. A NOx reduction efficiency of more than 90 % was obtained between 300 and 500 °C at α = NH3,in/NOx,in = 1. The catalyst showed stable NOx reduction efficiency after hydrothermal ageing at 700 °C. Sulfur poisoning promoted the NOx reduction efficiency at high temperatures at the expense of a reduced activity at lower temperatures, but the catalyst could be fully regenerated by heating in O2 at 650 °C.