Construction of Mn2O3/SmMn2O5 interface with tuned Mn coordination environment for efficient air pollutant elimination

Abstract

Gaseous pollutants can be efficiently removed by the mullite-type oxides. However, the enhancement effect is greatly limited due to the introduction of disordered defects and univariate regulation of conventional modification methods. Here, through interface engineering, we have successfully constructed the interface between Mn₂O₃ and SmMn₂O₅. The interface is formed during the in-situ calcination process. Various pollutants can be efficiently removed on Mn₂O₃/SmMn₂O₅ due to the interfacial effect. It has been demonstrated that the Mn-O bonds on the interface are stretched and easier to break due to the interfacial effect, thereby improving the redox ability and generating active oxygen species. The interfacial effect is effective in tuning the Mn coordination environment, which is the intrinsic reason for the efficient various pollutant removal ability of Mn₂O₃/SmMn₂O₅. Specifically, Mn₂O₃/SmMn₂O₅ shows one of the most promising Hg⁰ catalytic performances compared with reported catalysts, with a 75 % and 100 % Hg⁰ conversion rate under a space velocity of 1000000 h⁻¹ and 500000 h⁻¹, respectively. Mn₂O₃/SMO also exhibits a stable Hg⁰ conversion rate (100 %) at 100℃ for 50 h under a GHSV of 100000 h⁻¹. This work provides guidance for the rational design of efficient catalysts for various pollutant catalytic oxidations and other environmental applications.