Mesostructured Manganese Oxides for Efficient Catalytic Oxidation of Co, Ethylene, and Propylene at Mild Temperatures: Insight into the Role of Crystalline Phases and Physico-Chemical Properties

Abstract

Removing pollutants for indoor air purification is a key point to ensure the health and well-being of people in confined environments. This work aims to provide new insight into the development of promising manganese oxide catalysts. The effects of different crystalline phases (MnO2 and Mn2O3) and the role of redox properties and structural defects were investigated to abate indoor pollutants at mild temperatures. These materials were extensively characterized through complementary techniques and catalytic tests were performed to oxidize 100 ppm of CO, ethylene, or propylene. The most promising catalyst was obtained through solution combustion synthesis, achieving total removal at 118°C, 222°C, and 172°C, respectively, highest oxidation rate (2.41, 0.88, and 2.47 μmolg-1s-1) and lowest activation energy (50, 32 and 45 kJmol-1) for the three molecules. The synergy between crystalline phases enhanced the catalytic performance and their distribution in the structure was a crucial parameter affecting the number of structural defects.

Keywords: VOCs abatement, indoor air purification, nanocasting, solution combustion synthesis, structural defects.