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Indexed by:Journal Papers

Date of Publication:2020-04-27

Journal:ACS APPLIED ENERGY MATERIALS

Included Journals:SCIE

Volume:3

Issue:4

Page Number:3465-3476

ISSN No.:2574-0962

Key Words:reconstruction; Cu2O-CuO mixed oxide; DFT calculations; oxygen dissociated adsorption; bidentate nitrate

Abstract:Cubic cuprous oxide is applied in the selective catalytic oxidation of ammonia to nitrogen (NH3-SCO) to investigate the effect of structure evolution on catalytic performance. Different structures (Cu2O, Cu2O-CuO, and CuO) that formed progressively during the reconstruction process with time are discovered by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other characterization methods. The optimal CuO-Cu2O exhibits the best catalytic performance, which has T-100% = 210 degrees C and above 80% N-2 selectivity. Combining the experimental method and the density functional theory (DFT), the oxygen molecule is adsorbed in the form of a stable molecular state on Cu2O particles, while the dissociative adsorption of O-2 occurs over the mixed CuO-Cu2O and pure CuO phases. It is found that O-2 is more likely to be dissociated and activated on CuO-Cu2O with E-ads = -7.15 eV. There are three kinds of intermediate species (monodentate, bidentate, and bridging nitrate) observed. The formation of key bidentate nitrate species facilitates NH3 conversion and N-2 formation, but the other intermediate species have a negative effect on NH3 oxidation.