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

Abstract

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.