Active site exposure of sulfur-etched CeO₂ nanorods for nitrogen oxide reduction

CeO₂ is an extensively used catalyst in denitration reaction, however, weak acidity of CeO₂ is not conducive for NO conversion. Traditional sulfur etching by impregnation results in a large amount of sulfate deposition. To address this limitation, washing with deionized water was added following traditional impregnation (S_1.0-CeO₂-wash catalyst). The washing process successfully reduced the sulfate deposition, optimized the pore structure of the S_1.0-CeO₂-wash catalyst. The NO removal rate of the S_1.0-CeO₂-wash sample reached approximately 90% at 250–350 °C. Additionally, the Ce⁴⁺ content on the surface of S_1.0-CeO₂-wash catalyst increased. Moreover, the action of the S_1.0-CeO₂-wash catalyst in the reaction was determined to follow both Eley–Rideal (E–R) and Langmuir–Hinshelwood (L–H) mechanisms. This work provides a reference for the acid etching of other catalysts.