Amorphous FeOx–Mn0.1Oy catalyst with rich oxygen vacancies for ammonia selective catalytic reduction of nitrogen oxide at low temperatures

Abstract

Amorphous materials have garnered extensive research interest in heterogeneous catalysis because of their high surface area and interconnected micro/mesopores. In this study, an amorphous metal oxides (FeOx-Mn0.1Oy) with large surface areas, sufficient oxygen vacancies, excellent redox properties is prepared for the ammonia selective catalytic reduction (NH3-SCR) of NOx. Benefits from the large surface area, this catalyst possess higher adsorption and activation ability for O2 and NO which further enhanced the catalytic activity at low temperatures (90–240 °C). The incorporation of Mn into FeOx species inhibits the crystallization of hematite, further resulting in an increase of the surface area and surface acid sites in the as-prepared catalyst. Furthermore, the number of oxygen vacancies increases by the incorporation of manganese, which reduces the apparent activation energy of hematite and enhances the redox property of the amorphous FeOx–MnOy catalyst. The reaction mechanism of this catalyst also has been proposed based on the result of in situ DRIFTs experiment results.