Study on NH3-SCR Activity and HCl/H2O Tolerance of Titanate-Nanotube-Supported MnOx-CeO2 Catalyst at Low Temperature

Manganese oxide-cerium oxide supported on titanate nanotubes (i.e., MnCe/TiNTs) were prepared and their catalytic activities towards NH3-SCR of NO were tested. The results indicated that the MnCe/TiNT catalyst can achieve a high NO removal efficiency above 95% within the temperature range of 150-350 degrees C. Even after exposure to a HCl-containing atmosphere for 2 h, the NO removal efficiency of the MnCe/TiNT catalyst maintains at approximately 90% at 150 degrees C. This is attributed to the large specific surface area as well as the unique hollow tubular structure of TiNTs that exposes more Ce atoms, which preferentially react with HCl and thus protect the active Mn atoms. Moreover, the abundant OH groups on TiNTs serve as Br & oslash;nsted acid sites and provide H protons to expel Cl atom from the catalyst surface. The irreversible deactivation caused by HCl can be alleviated by H2O. That is because the dissociated adsorption of H2O on TiNTs forms additional OH groups and relieves HCl poisoning.