Ozone, which has been widely used as a strong oxidant, is also a kind of indoor air pollutant. Nowadays some common machines in our rooms such as photocopiers and laser printers can lead to considerable ozone emission. Exposure to high concentration ozone causes damage to human health including pulmonary disease and airway inflammation. Among those catalytic materials explored for eliminating O3 like noble metal and transition metal oxides, manganese dioxide attracts most attention. In our study, α-MnO2 (cryptomelane) has been modified by introducing a certain amount of tungsten into the structure. We have synthesized the catalyst via the hydrothermal treatment, a chemical oxidation-reduction reaction between MnO4- and Mn2+ in the presence of WO42-. By controlling the experimental conditions such as precursors, ratio and temperature, we can have different morphology and crystal structures of materials. As-prepared MnO2 with the introduction of hexavalent W (the atomic ratio W/Mn=6%) exhibited high surface area (297 m2/g) as well as excellent activity for ozone decomposition under both dry and humid condition. Moreover, after the heating treatment at 673K, the tungsten-doped manganese dioxide material with better catalytic activity and stability was obtained, which can completely eliminate high concentration ozone (100ppm) at room temperature without inactivation phenomenon even after several hours. In consideration of the high valence characteristic, adding tungsten has impacted on the growth of crystals to change the lattice structure during the reaction process and affected the existence form of manganese. It's pointed out that doping kinds of metals with a high valence is considered to be a promising method to prepare more effective ozone-decomposition catalyst.

Tungsten-doped manganese dioxide for ozone removal

253rd National Meeting (2017)

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