Selective catalytic oxidation of ammonia to nitrogen over MnO2 prepared by urea-assisted hydrothermal method

Abstract Selective catalytic oxidation of ammonia was studied over MnO 2 catalysts synthesized by urea-assisted and tranditional hydrothermal method. A contrastive research was also made to a commercial MnO 2 catalyst. The catalytic performance of MnO 2 for NH 3 -SCO was found to be connected with the properties of the catalysts which were obviously determined by the preparation methods. The best catalytic activity was achieved at 170 °C over the MnO 2 synthesized by urea-assisted hydrothermal method. The properties of catalysts were characterized by BET, XRD, SEM, XPS, H 2 -TPR and NH 3 -TPD techniques. And it was found that MnO 2 prepared by urea-assisted synthetic method showed larger surface area and lower reduction temperature. Abundant NH 3 adsorption sites and oxygen vacancies were formed on its surface compared to the other catalysts, which evidently enhanced the catalytic performance for NH 3 selective oxidation.