1 research outputs found
In Situ Spectroscopic and Computational Studies on a MnO<sub>2</sub>–CuO Catalyst for Use in Volatile Organic Compound Decomposition
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<sub>2</sub>–CuO catalyst. The catalytic activity
of MnO<sub>2</sub>–CuO was higher than that of MnO<sub>2</sub> at low temperatures, although the pore properties of MnO<sub>2</sub> were similar to those of MnO<sub>2</sub>–CuO. In addition,
whereas the chemical state of MnO<sub>2</sub> remained constant following
PGMEA dosing at 150 °C, MnO<sub>2</sub>–CuO was reduced
under identical conditions, as confirmed by in situ NEXAFS spectroscopy.
These results indicate that the presence of Cu in the MnO<sub>2</sub>–CuO catalyst enables the release of oxygen at lower temperatures.
More specifically, the released oxygen originated from the Mn–<u>O</u>–Cu moiety on the top layer of the MnO<sub>2</sub>–CuO structure, as confirmed by calculation of the oxygen
release energies in various oxygen positions of MnO<sub>2</sub>–CuO.
Furthermore, the spectral changes in the in situ NEXAFS spectrum of
MnO<sub>2</sub>–CuO following the catalytic reaction at 150
°C corresponded well with those of the simulated NEXAFS spectrum
following oxygen release from Mn–<u>O</u>–Cu.
Finally, after the completion of the catalytic reaction, the quantities
of lactone and ether functionalities in PGMEA decreased, whereas the
formation of Cî—»C bonds was observed