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Development of a copper–lanthanum oxide catalyst for the removal of gaseous ammonia by catalytic oxidation: Physicochemical and electrochemical characterization of catalyst materials
Author(s) -
Hung ChangMao
Publication year - 2013
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.3061
Subject(s) - catalysis , lanthanum oxide , inorganic chemistry , redox , copper , lanthanum , oxide , chemistry , ammonia , copper oxide , electrochemistry , incipient wetness impregnation , selectivity , electrode , organic chemistry
SUMMARY The aim of this study was to develop a CuO/La 2 O 3 catalyst to perform the oxidation of ammonia (NH 3 ) to form nitrogen by selective catalytic oxidation (SCO). This catalyst was fabricated by the incipient wetness impregnation technology in a tubular fixed‐bed flow quartz reactor. Under optimum conditions, at a temperature of 723 K and an oxygen content of 4%, approximately 97% of the NH 3 was removed by catalytic oxidation over the CuO/La 2 O 3 (8:2, molar/molar) catalyst, suggesting the presence of a synergetic effect between CuO and La 2 O 3 . N 2 was the main product of the NH 3 –SCO process. The surface properties of the catalyst were analyzed by fluorescent spectroscopy (FS) combined with UV–Vis absorption, dynamic light scattering, zeta potential measurements, cyclic voltammograms (CV), and polarization methods. These studies have shown that the catalytic behavior observed is related to the copper (II) oxide, while rare earth‐lanthanum (III) oxide may serve only to provide active sites for the reaction during a catalyzed oxidation experiment. FS and UV–Vis measurements revealed that copper and lanthanum clusters were present on the catalyst surface. Additionally, FS has been applied to evaluate the catalyst yields with fluorescent plots of 280 nm, 445 nm, and 500 nm. These results suggest that FS is an appropriate and effective method to characterize Cu clusters that enhance their intrinsic emission from a CuO/La 2 O 3 catalyst in catalytic treatment systems. The reversible redox ability of these catalysts observed during CV studies may explain their significant activity. Copyright © 2013 John Wiley & Sons, Ltd.