Inspecting Promotive Functions of Antimony Oxides for NH3-Assisted Selective Catalytic NOX Reduction

Abstract

It is widely accepted that Sb oxide promotes redox cycling feature and SO<sub>2</sub> resistance of a catalyst utilized for selective catalytic NO<sub>X</sub> reduction (SCR) at low temperatures (≤300 ℃). However, promotive roles of Sb oxide have never been explored with the alteration of its crystal phases, which can be crucial to direct the overall acidic/redox characteristics and SCR performance of a catalyst along with its SO<sub>2</sub> tolerance. In this regard, while implementing TiO2-supported Mn oxide (Mn) as a model catalyst, we successfully isolated Sb<sub>2</sub>O<sub>3</sub> and Sb<sub>2</sub>O<sub>5</sub> on Mn using wet impregnation and precipitation protocols, leading to produce Mn-Sb-I and Mn- Sb-P, respectively. The resulting catalysts were verified to have comparable acidic properties, yet, exhibit distinct redox traits, as evidenced by the greatest quantity of labile oxygens for Mn-Sb-I (Sb<sub>2</sub>O<sub>3</sub>) compared to Mn and Mn-Sb-P (Sb<sub>2</sub>O<sub>5</sub>). This leads to significant enhancement of SCR performance and SO<sub>2</sub> resistance for Mn-Sb-I over the others.