Production of an effective catalyst with increased oxygen vacancies from manganese slag for selective catalytic reduction of nitric oxide.

Abstract Manganese slag is a solid waste produced by the steel industry and usually lacks a proper recycling. In this paper, the manganese slag was used to synthesize a catalyst via microwave assistant method and applied in selective catalytic reduction of nitric oxide. As a result, the catalyst exhibited an excellent low-temperature activity. It removed 78.31% of nitric oxide at 100 °C, 44.44% higher than that of a slag-derived catalyst synthesized by ammonia impregnation, and 63.18% higher than that of a commercial catalyst. Even after a hydrothermal treatment, the catalyst still showed a removal of 69.26% at 150 °C. After a detailed characterization, the low-temperature activity was attributed to an increased amount of oxygen vacancies, which were generated during the microwave synthesis. The generated oxygen vacancies provided adsorption sites for chemisorbed oxygens, which then promoted the electron transfer for reduction of nitric oxide. The main result of this work will help to develop a low-cost catalyst and obtain a high-value-added utilization of manganese slag at the same time. Graphical abstract Image 1 Highlights • A catalyst was synthesized directly from manganese slag. • The slag-derived catalyst was effective than a commercial catalyst in SCR. • The excellent activity was attributed to the higher active components. • The active components included Mn3/4+ species and chemisorbed oxygen. [ABSTRACT FROM AUTHOR]