Fabrication, characterization, and evaluation of the cytotoxicity of platinum–rhodium nanocomposite materials for use in ammonia treatment

This work describes the oxidation of ammonia (NH3) at temperatures between 423 and 673 K by selective catalytic oxidation (SCO) over a Pt–Rh nanocomposite catalyst that was prepared by the co-precipitation of H2PtCl6 and Rh(NO3)3 in a tubular fixed-bed flow quartz reactor (TFBR). The catalysts were characterized using TEM, XRD, PSA, and CV. The experimental results reveal that at a temperature of 673 K and an oxygen content of 4%, approximately 98% of the NH3 was removed by catalytic oxidation over the Pt–Rh nanocomposite catalyst. N2 was the main product of the NH3-SCO process. The Pt–Rh nanocomposite-induced cytotoxicity to the human lung cell line, MRC-5, was tested, and cell survival was determined using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetra-zolium (MTS) analysis in vitro. These results demonstrated that the Pt–Rh nanocomposite catalyst is only weakly cytotoxic to human lung cells.