Preparation, Performance, and Cytotoxicity Evaluation of Nanoarchitectures CuO/CeO ₂ Composite Catalysts for the Catalytic Decomposition of Ammonia

This work discusses the oxidation of ammonia (NH ₃) at temperatures between 150 and 400°C (423 and 673 K) by selective catalytic oxidation (SCO) over a nanoarchitectures CuO=CeO ₂ composite catalyst that was prepared through coprecipitation (CP) method of copper nitrate and cerium nitrate at molar ratio of 7:3. The catalysts were characterized using thermogravimetric analysis (TGA), BET, analytical scanning transmission electron microscopy (AEM), and cyclic voltammetric (CV) measurement. The experimental results demonstrate that the presence of ammonia was removed around 97% NH ₃ reduction was achieved during catalytic oxidation over the nanoarchitectures CuO=CeO ₂ composite catalyst calcine treated at 500°C (773 K) with an oxygen content of 4%. The composite particles were characterized by AEM, with a particle size around nanoscale particle sizes (~5 nm) with high dispersion phenomena. The nanoarchitectures CuO=CeO ₂ composite-induced cytotoxicity in the human lung cell line, MRC-5, was tested, and cell survival was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetra-zolium (MTS) analysis in vitro. These results indicated that the nanoarchitectures CuO=CeO ₂ composite catalyst is only weakly cytotoxic to human lung cells.