The effect of Ni on selective catalytic reduction of NOx with NH3 over 2.5% Cu/rare earth tailings

The modification of 2.5% Cu/rare earth tailings with the introduction of Ni was carried out by adopting the impregnation-hydrothermal method, while the effects of Ni modification on the denitrification performance of 2.5% Cu/rare earth tailings catalyst were investigated by XRD, BET, TPR, TPD and XPS and other characterizations. The results demonstrated that the denitrification performance of the rare earth tailings catalyst was significantly superior to that of the monometallic Cu modification after Cu and Ni bimetallic modification, while the reaction temperature window was broadened to 150-400 degrees C. The denitrification activity of 2% Ni/2.5% Cu/ rare earth tailings catalyst at 300 degrees C was 90%. Upon the addition of Ni, the strong electron interaction between Fe-Ni-Cu resulted in the electron shift between Cu-Fe and Ni-Fe, which in turn constituted a new electron transfer system, and provided the basis for the formation and adsorption of nitrate species. Moreover, the Ni-Fe synergistically obtained NiFe2O4 spinel structure increased the catalyst specific surface area and exposed more active sites, while the Ni-Cu synergistically enabled the increase of oxygen vacancies in CuO, thereby enhancing the amount of reactive oxygen species and the redox ability of the catalyst. The combined effect between the three elements was strongest in the 2% Ni/2.5%/Cu rare earth tailings catalyst. The use of rare earth tailings as raw materials and the selection of suitable elements for loading achieve the clean and efficient use of waste, which is in line with the development requirements of green development of catalysts.