SBA-15 Templated Mesoporous MnOx for Catalytic Ozonation of Toluene

• Published in: Catalysis letters Vol. 150; no. 2; pp. 365 - 374
• Main Authors: Yuan, Yue, Qin, Zhiyuan, Xu, Zhongjun
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.02.2020; Springer Nature B.V
• Subjects: Adsorption; Catalysis; Catalysts; Chemistry; Chemistry and Materials Science; Decomposition reactions; Industrial Chemistry/Chemical Engineering; Manganese dioxide; Manganese oxides; Organometallic Chemistry; Oxidation; Ozone; Physical Chemistry; Reaction mechanisms; Selectivity; Toluene; Valence; Catalytic ozonation; Mesoporous MnO; Toluene; catalysts
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-019-03000-5

γ-MnO 2 , β-MnO 2 and Mn 2 O 3 with mesoporous structure were prepared as catalysts by using SBA-15 as hard template at different calcination temperatures. The catalysts were characterized by XRD, HRTEM, N 2 adsorption–desorption, XPS, FTIR. The activity of three catalysts for catalytic ozonation of toluene followed the order of β-MnO 2  > γ-MnO 2  > Mn 2 O 3 . The results showed that the mesoporous β-MnO 2 exhibited the best catalytic performance because it has the highest average oxidation state of Mn and the most abundant surface adsorbed oxygen. Specifically, the toluene conversion could reach to 100% and the CO 2 selectivity could reach up to 83% at 70–90 mg/m 3 of toluene concentration over the catalyst. It can be inferred that reaction mechanism consists of two cycles including ozone decomposition and toluene adsorption on active sites of β-MnO 2 , which obeys L–H mechanism. The active oxygen (O*) produced in the first cycle can oxidize the toluene molecule adsorbed in the second cycle. Simultaneously, the mesoporous β-MnO 2 had good stability, which reflected that it showed good performance on the catalytic ozonation of toluene during the 47-day test. In summary, this work makes it possible to remove VOCs for reality. Graphic Abstract