Promoting the catalytic performance by tungstophosphoric acid modification Fe0.15Ce0.85 bimetal oxide catalysts for NH3-SCR

• Published in: Fuel (Guildford) 2025-02, Vol.381, p.133457, Article 133457
• Main Authors: Huang, Chengheng, Gu, Shifei, Qin, Qiuju, Han, Xiaorong, Mo, Donghai, Chen, Zhengjun, Li, Bin, Zhang, Hongyan, Dong, Lihui
• Format: Article
• Language: English
• Subjects: Fe-Ce oxide; NH3-SCR; SO2 resistance; Tungstophosphoric acid
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.133457

The tungstophosphoric acid(HPW) improved the 0.2H-Fe0.15Ce0.85 catalyst NO conversion and resistance to SO2 by facilitating the adsorption and activation of NH3, increasing the surface adsorbed oxygen and adjusting the redox property. HPW facilitates the redox cycle between Ce4+ and Ce3+, increasing oxygen vacancies and improving oxygen storage and release capacity. The adsorbed ammonia species on surface acid sites convert to bidentate nitrate species with abundant surface adsorbed oxygen, which improved the reaction between NH3/NH4+ and NOx and followed by the L-H mechanism. [Display omitted] •0.2H-Fe0.15Ce0.85 exhibited superior SCR activity and satisfactory SO2 resistance.•The HPW increases Brønsted acid sites and facilitates the adsorption and activation of NH3.•HPW facilitates the redox cycle between Ce4+ and Ce3+, increasing oxygen vacancies.•HPW improves the reaction following both E-R and L-H mechanisms. The SO2 resistance for Ce-based catalysts is a significant challenge for practical application in NH3-SCR. Herein, a series of the tungstophosphoric acid (HPW) modification Fe-Ce bimetal oxide catalysts are prepared by a one-pot sol-gol strategy. The 0.2H-Fe0.15Ce0.85 catalyst exhibits more than 90 % NO conversion at 225–375 °C and satisfactory SO2 resistance under a GHSV of 60000 h−1. The HPW increases abundant Brønsted acid sites on the catalyst surface while facilitating the adsorption and activation of NH3. The XPS and O2-TPD analysis showed that the HPW facilitates the redox cycle between Ce4+ and Ce3+, increasing oxygen vacancies and improving oxygen storage and release capacity. Additionally, in situ DRIFTS indicated that L-H and E-R mechanisms existed in the Fe0.15Ce0.85 and 0.2H-Fe0.15Ce0.85 catalysts. The adsorbed ammonia species on surface acid sites converted to bidentate nitrate species with the assistance of abundant surface adsorbed oxygen, which improved the reaction between NH3/NH4+ and NOx and followed by the L-H mechanism.