The effect of tourmaline on the denitration performance of MnOx/TiO2 catalysts and DFT calculation

Abstract

Development of the efficient MnOx/TiO2 catalysts with high dispersibility and stability of denitration reaction for NH3-SCR is crucial to control NOx emission at low temperature. Herein, we propose mineral polarization effect modification on the surface of MnOx/TiO2 denitration catalytic material via coprecipitation method using tourmaline as modifying agent, and evaluate its performance of NOx removal. Particularly, tourmaline-MnOx/TiO2 catalysts presented a high denitration rate about 97% under the condition of 1000 ppm NO, 1000 ppm NH3 and 5% O2 at 200 °C and maintained above 91% removal efficiency within 10 h, which was mainly ascribed to the polarization effect of tourmaline. The doping of tourmaline could improve the dispersion of catalytic materials, reduce the band gap width, and promote the activation of NH3 and the oxidation of NO. Moreover, the microscopic mechanism was studied by density functional theory (DFT) calculation from the aspects of adsorption energy, mulliken charge and density of states during the adsorption process. Overall, the results of this study will provide references for the application of mineral polarization effect to the field of denitration catalysis and promotes the further understanding of the mechanism for deNOx reaction process.