Production of Copper-Based Rare Earth Composite Metal Materials by Coprecipitation and Applications for Gaseous Ammonia Removal

ABSTRACT

This study addresses the oxidation of ammonia (NH₃) at temperatures between 423 and 673 K by selective catalytic oxidation (SCO) over a copper-based, rare earth composite metal material that was prepared by coprecipitating copper nitrate, lanthanum nitrate, and cerium nitrate at various molar ratios. The catalysts were characterized using Brunner, Emmett, and Teller spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, ultraviolet–visible spectroscopy, cyclic voltammetric spectroscopy, and scanning electron microscopy. At a temperature of 673 K and an oxygen content of 4%, approximately 99.5% of the NH₃ was reduced by catalytic oxidation over the 6:1:3 copper-lanthanum-cerium (molar ratio) catalyst. Nitrogen (N₂) was the main product of this NH₃-SCO process. Results from the activity and selectivity tests revealed that the optimal catalyst for catalytic performance had the highest possible cerium content and specific surface area (43 m²/g).

IMPLICATIONS

NH₃ is an important chemical product of diverse industrial processes, including ammonium nitrate production, livestock feedlots, urea manufacturing, N₂ fertilizer production, fossil fuel combustion, petroleum refining, and the refrigeration industry. This work addresses the oxidation of NH₃ by copper-based, rare earth composite metal materials with various relevant parameters. The effectiveness of this catalyst for NH₃ removal by SCO is investigated.

ACKNOWLEDGMENTS

The author thanks the National Science Council of the Republic of China, Taiwan, for partial financial support of this research under contract no. NSC 98-2221-E-132-003-MY3.