The effect of tungsten doping on the catalytic activity of alpha-MnO2 nanomaterial for ozone decomposition under humid condition

Ozone is a universal air pollutant and its stable decomposition under humid condition is still a challenge. In this work, the effect of tungsten doping on the activity of alpha-MnO2 for ozone decomposition was first investigated. Tungsten was doped into MnO2 with addition of tungstate in a hydrothermal reaction solution. The as-synthesized catalysts were characterized by XRD, SEM, TEM, BET, XPS, ICP-AES, Raman, H-2-TPR, O-2-TPD, NH3-TPD and EPR. The results indicated that doping of tungsten made the morphology change from nanorods to nano particles with great increase of specific surface area. In addition, more oxygen vacancies were formed, and the surface acidity was greatly enhanced, accordingly the tungsten-doped MnO2 exhibited enhanced activity and stability at room temperature under dry and particularly under humid condition (RH = 65%). It indicates that the doping with a high valence metal such as W6+ into MnO2 is a promising method to obtain efficient ozone decomposition catalyst.