Effective Ti Doping of δ-MnO2 via Anion Route for Highly Active Catalytic Combustion of Benzene

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• 作者：Dongyan Li ; Wenhui Li ; Yuzhou Deng ; Xiaofeng Wu ; Ning Han ; Yunfa Chen
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：May 19, 2016
• 年：2016
• 卷：120
• 期：19
• 页码：10275-10282
• 全文大小：605K
• 年卷期：0
• ISSN：1932-7455

文摘

Due to its unique layered structure compared with those tunnel structures of α-, β-, and γ-MnO₂, δ-phase MnO₂ is widely investigated as pollutant degradation catalysts, supercapacitor cathodes, and so forth. However, it is still challenging to effectively dope the δ-MnO₂ to improve its performance although doping of other structures has been widely reported. In this study, a facile anion route is used to dope Ti in hydrothermal process for preparation of highly active hierarchical δ-MnO₂ catalyst. The Ti doping process is performed successfully at a growth temperature of 140 °C, considering keeping the active δ-phase and producing the active lattice oxygen, which is identified by X-ray diffraction patterns (XRD), X-ray photoelectron spectra (XPS), and Raman spectra. On the other hand, low temperature (<120 °C) induces low doping concentration (<0.5 atom %) and high temperature (>160 °C) changes the δ-phase to α-phase. The doping process is proposed to be the incorporation of the hydrolyzed [Ti(OH)₆]^2– into the [MnO₆] sheets with similar octahedral structure. The Ti-doped δ-MnO₂ has the highest catalytic oxidation property over benzene, which can be attributed to both the active oxygen induced by Ti doping, and the abundant pore structures, such as the interlayer spaces (∼0.7 nm), mesopores (e.g., 4–5 nm and 8–9 nm), and macropores between the nanoflake assembles facilitating the gases diffusion and reactions. All these results hold the promise for the effective anion doping route for δ-MnO₂ applied in high efficiency and low cost degradation of volatile organic compound contamination in air as well as in other catalytic applications.