The effect of the calcination temperature on the activity of Cu–La–Ce composite metal catalysts for the catalytic wet oxidation of ammonia solution

Aqueous solutions that contained 400 mg/L of ammonia were oxidized in a batch reactor in this study of Cu–La–Ce composite metal catalysts, which were prepared by the co-precipitation with aqueous solutions of copper nitrate, lanthanum nitrate and cerium nitrate. Results demonstrated that the conversion of ammonia by wet oxidation in the presence of Cu–La–Ce composite metal catalysts followed by calcinations temperature ranging from 773 to 973 K. The ammonia solutions were removed, while around 95% of the ammonia was reduced during the wet oxidation over the Cu–La–Ce composite metal catalyst calcined at 773 K and an oxygen partial pressure of 4.0 MPa. Furthermore, the catalysts were characterized using XRD, FTIR, UV-Vis, BET, PSA and TEM, has shown that the catalytic behavior is related to the copper (II) oxide, while lanthanum (III) and cerium (IV) oxide may serve only to provide active sites for the reaction during a catalyzed wet oxidation run.

Graphical abstractThe catalytic reaction using the Cu–La–Ce composite metal catalyst, wherein the ammonia conversion rate exceeded 60% at 773 K. Consequently, higher calcination temperatures correspond to a higher conversion yield. Additionally, the textures of the catalysts were observed also to depend on the metal loading and the calcination temperature.Figure optionsDownload full-size imageDownload as PowerPoint slide