CeFe-supported gold active catalyst applied to NO-SCR by CO: Effect of the gold deposition method and pretreatment

Abstract

We demonstrate the effect of two preparation methods of gold catalysts (<1 wt%) –colloidal method, Au(CM), and deposition-precipitation, Au(DP)– and three pretreatments on the activity of Ce0.8Fe0.2O2-supported catalysts in the NO-SCR by CO. Au(CM) (Tlight-off = 256 °C) displays activity inferior to the support (Tlight-off = 186 °C) after all pretreatments, attributed to surface composition and stable‑carbonate formation. Au(DP) pretreated with O2 at 200 °C (Tlight-off = 82 °C) displays activity higher than the support. Auδ+-OH sites were evidenced by XPS and DRIFTS on Au(DP), key to converting CO to CO2 at lower temperatures, in turn, producing oxygen vacancies, responsible for reducing NO to N2.

Keywords

• CeFe-supported gold catalysts
• NO-SCR by CO
• Au deposition method
• Au colloidal method
• Oxygen vacancies