Effect of K+ ions on efficient room-temperature degradation of formaldehyde over MnO2 catalysts

• Published in: Catalysis today 2019-05, Vol.327, p.154-160
• Main Authors: Fang, Ruimei, Feng, Qiuyu, Huang, Haibao, Ji, Jian, He, Miao, Zhan, Yujie, Liu, Biyuan, Leung, Dennis Y.C.
• Format: Article
• Language: English
• Subjects: Catalytic oxidation; Formaldehyde; Indoor air; Manganese oxide
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2018.05.019

The figures are formaldehyde degradation and residual K+ concentration of different MnO2 catalysts. [Display omitted] •δ-MnO2 was prepared via facile in-situ redox reaction.•Residual K+ ions of δ-MnO2 improved the catalytic activity for HCHO oxidation.•HCHO removal efficiency kept at 100% during 600 min.•Residual K+ ions improved the amount and redox ability of surface mobile oxygen. δ-MnO2 was prepared via a facile in-situ redox reaction and used for catalytic oxidation of HCHO, a major indoor air pollutant. The washing treatment during catalyst preparation could impose great effect on content of K+ and catalytic activity. δ-MnO2 catalyst without washing treatment contains the highest content of K+ ion and exhibits the best catalytic activity among various δ-MnO2 samples. The HCHO removal efficiency keeps at 100% for first 600 min. The δ-MnO2 samples were characterized by advanced technologies including XRD, Raman, XPS, TPR, TPD and in-situ DRIFTS. The XPS results indicates that K+ ions increases the AOS value of Mn and the ratio of surface-adsorbed oxygen over δ-MnO2. The content of K+ ions improves the amount and redox ability of surface mobile oxygen species, enhancing catalytic oxidation of HCHO.