摘要

In the nitric acid industry, platinum loss is the second largest cost due to vaporization of the Pt gauze catalyst at high temperature. In this research, Pt is loaded on TiO2, ZrO2, CeO2, and ceria zirconia solid solution by photoreduction and used as catalysts for ammonia oxidation. Results show that Pt content of the obtained catalysts is effectively reduced to 0.08 wt but their catalytic performance is better than that of the traditional Pt gauze between 300 and 800 degrees C. The best catalyst, 3Pt@ CeO2 with 0.0797 wt % Pt content, enabled complete ammonia transformation at 300 degrees C and 80% NOx yield at 800 degrees C with the space velocity of 235 000 h(-1) and the oxygen-to-ammonia ratio of 15 in ambient pressure. After 50 h of continuous operation, no observable decay in performance was detected. Such excellent performance is ascribed to the lattice oxygen provided by CeO2 and the formation of Pt-Ce-O. These results provide a promising method of improving the current industrial Pt catalysts.