Water-promoted low-concentration NO removal at room temperature by Mg-doped manganese oxides OMS-2

Nanostructured magnesium doped manganese oxides (Mg-SC-OMS-2) was prepared through doping Mg into OMS-2 using an ultrasound-assisted approach. This Mg-SC-OMS-2 material showed low crystallinity with a large surface area and extensive defects which are totally different from those synthesized by conventional method. Extraordinarily high NO removal performance was obtained. It retained 99% NO removal ratio for as long as 8 h under extremely high space velocity of 120,000 mL/g/h. More attractively, when water vapor was introduced, above 50% removal ratio of catalyst was maintained for as long as 250 h. The high catalytic activity of Mg-SC-OMS-2 is associated with presence of redox pair Mn³⁺/Mn⁴⁺ and activated oxygen species at oxygen vacancies occurring via the pathway of Mars-van Krevelen mechanism.