Performance optimization of a MnO2/carbon nanotube substrate for efficient catalytic oxidation of low-concentration NO at room temperature

Modified nanosheet (NS) MnO2 upon carbon nanotubes (CNT) has been synthesized via doping methods or acid treatment during a hydrothermal reaction. Compared to other mixed oxides (MnO2/CeO2, MnO2/ZrO2, MnO2/TiO2), the MnO2/CNT series has higher surface areas and better activity on the oxidation of low-concentration (10 ppm) NO at room temperature. In addition, the acidulated MnO2/CNT shows high NO selectivity to NO2 for surface acidity promotes the dissociative adsorption of O2. What's more, Ti-doped MnO2/CNT has high stability in a moist stream of simulated feed gas with the increase of H2O desorption. It proves that the surface hydroxyls contribute to NO adsorption and provide an oxygen source for the process of NO oxidation. The primary reaction pathway was proposed to be responsible for the catalytic conversion of NO and O2 into NO2.