Ozone Decomposition below Room Temperature Using Mn-based Mullite YMn2O5

• DOI: 10.1021/acs.est.1c08922
• Publication Date: 2022-05-26T16:45:09Z
• Authors: Xiang Wan; Lijing Wang; Shen Zhang; Haozhe Shi; Juntao Niu; Gen Wang; Weifang Li; Da Chen; Haijun Zhang; Xiaomeng Zhou; Weichao Wang
• Keywords: Oxygen; Ozone; Temperature; Aluminum Silicates; Oxides; 01 natural sciences; Catalysis; 0105 earth and related environmental sciences

A super-low-temperature ozone decomposition is realized without energy consumption on a ternary oxide catalyst mullite YMn2O5 for the first time. The YMn2O5 oxide catalyzed ozone decomposition from a low temperature of -40 °C with 29% conversion (reaction rate: 1534.2 μmol g-1 h-1) and quickly reached 100% (5459.5 μmol g-1 h-1) when warmed up to -5 °C. The superior low-temperature performance over YMn2O5 could surpass that of the reported ozone decomposition catalysts. The structure and element valence characterizations confirmed that YMn2O5 remained the same after 100 h of room-temperature reaction, indicating excellent durability of the catalyst. O2-TPD (O2-temperature-programmed desorption) showed that the active sites are the Mn3+ sites bonded with singly coordinated oxygen on the surface. Combined with in situ Raman measurements and density functional theory calculations, we found that the ozone decomposition reaction on YMn2O5 showed a barrier of only 0.29 eV, following the Eley-Rideal (E-R) mechanism with a rate-limiting step of intermediate O22- desorption. The low barrier minimizes the accumulation of intermediate products and realizes the fast O3 decomposition even at super-low temperatures. Fundamentally, the moderate Mn-O bonding strength in the low-symmetry ternary oxides is crucial to produce singly coordinated active species on the surface responsible for the efficient ozone degradation at low temperatures.