In situ synthesis of low-valence MnO/Mn3O4 catalyst via carbon-acid hydrothermal strategy for NO removal

Abstract

A rational design of high dispersion MnO/Mn 3 O 4 catalysts based on carbon-acid hydrothermal strategy was proposed for selective catalytic reduction of NO at low temperature. The ultra-high denitration rate can be attributed to the abundant Lewis acid sites and reactive oxygen species, and the reaction followed Langmuir-Hinshelwood reaction route. • High dispersed MnO/Mn 3 O 4 catalyst was prepared by carbon-acid hydrothermal method. • Catalyst achieved exceeding 98 % NO removal in the temperature window of 80–200 °C. • Rich Lewis acid sites and reactive oxygen species contributed to high SCR activity. • In-situ DRIFTS proved the SCR reaction process followed Langmuir-Hinshelwood route. A rational design of high dispersion MnO/Mn 3 O 4 catalysts based on carbon-acid hydrothermal strategy was proposed for selective catalytic reduction of NO at low temperature. The reaction mechanisms of low valence manganese coordination and catalytic path were revealed through active site analysis and in-situ DRIFTS characterization. The results showed that reasonable low valence manganese nanofibers cooperated to derive hierarchical mesoporous structure and abundant surface active oxygen. The chemisorbed oxygen specie cooperated with Lewis acid sites accelerated the production of NO 2 in the catalytic process and realized high-efficiency NO removal at ultra-low temperature. Such a facile preparation method of low valence manganese nanofibers structure widens the way for NH 3 -SCR of NO in industrial practice.