In Situ Spectroscopic and Computational Studies on a MnO(2)–CuO Catalyst for Use in Volatile Organic Compound Decomposition

[Image: see text] In situ near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory calculations were conducted to demonstrate the decomposition mechanism of propylene glycol methyl ether acetate (PGMEA) on a MnO(2)–CuO catalyst. The catalytic activity of MnO(2)–CuO was higher than that of MnO(2) at low temperatures, although the pore properties of MnO(2) were similar to those of MnO(2)–CuO. In addition, whereas the chemical state of MnO(2) remained constant following PGMEA dosing at 150 °C, MnO(2)–CuO was reduced under identical conditions, as confirmed by in situ NEXAFS spectroscopy. These results indicate that the presence of Cu in the MnO(2)–CuO catalyst enables the release of oxygen at lower temperatures. More specifically, the released oxygen originated from the Mn–O–Cu moiety on the top layer of the MnO(2)–CuO structure, as confirmed by calculation of the oxygen release energies in various oxygen positions of MnO(2)–CuO. Furthermore, the spectral changes in the in situ NEXAFS spectrum of MnO(2)–CuO following the catalytic reaction at 150 °C corresponded well with those of the simulated NEXAFS spectrum following oxygen release from Mn–O–Cu. Finally, after the completion of the catalytic reaction, the quantities of lactone and ether functionalities in PGMEA decreased, whereas the formation of C=C bonds was observed.