Catalytic performance of acidic zirconium-based composite oxides monolithic catalyst on selective catalytic reduction of NOx with NH3

• CeO2–ZrTiSiWOx catalysts show good NH3-SCR performance.
• An optimal CeO2 loading and adding method exist providing high activity and broad reaction window.
• 10% CeO2/ZrTiSiWOx displays an excellent NOx activity and N2 selectivity.
• The catalyst presents a strong tolerance to GHSV, H2O, SO2 and hydrothermal aging.

A series of monolithic acidic zirconium-based composite oxide catalyst (Ce–ZrTiSiWOx) were prepared by different introduction methods and loading contents of CeO2 for selective catalytic reduction (SCR) of NOx with ammonia. In this work, a acidic zirconium-based composite oxide (10 wt.% CeO2/ZrTiSiWOx) catalyst prepared only by impregnation method presented good NH3-SCR activity and high N2 selectivity in a broad operation temperature window, comparative strong tolerance of gas hourly space velocities (GHSV), water, sulfur and hydrothermal aging. Compared with V2O5/TiSiWOx and Fe-ZSM-5 catalysts, the CeO2/ZrTiSiWOx catalyst showed a better NH3-SCR performance and higher thermal aged performance. More than 80% NOx could be removed in the temperature range of 277–545 °C under GHSV of 30,000 h−1 over the monolithic 10 wt.% CeO2/ZrTiSiWOx catalyst. More surface atomic concentration of Ce, strong reducible ability and the maximum acid amount are important reasons for the high NH3-SCR activity of the CeO2/ZrTiSiWOx catalyst.

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