One-pot synthesis of ceria and cerium phosphate (CeO2-CePO4) nanorod composites for selective catalytic reduction of NO with NH3: Active sites and reaction mechanism

In this work, novel (CeO 2 ) x -(CePO 4 ) 1−x (defined as Ce x P 1−x ) nanorod composites were prepared by a simple co-precipitation method, and the influence of CeO 2 on the catalytic performance of CePO 4 for selective catalytic reduction of NO by NH 3 (NH 3 -SCR of NO) was investigated. The catalytic performance evaluation revealed that the Ce x P 1−x catalysts, especially Ce 0.2 P 0.8 exhibited a much better catalytic activity and H 2 O + SO 2 resistance than CePO 4 . Structure characterizations via high-resolution transmission electron microscope (HRTEM) and Brunauer-Emmett-Teller (BET) revealed that the introduction of CeO 2 had a little effect on the shape of CePO 4 nanorods and it could promote the formation of new mesoporous then significantly enhance the surface area of catalyst. The analysis results of active sites suggested that phosphorus was the main adsorption site for NH 3 and the redox sites were controlled by CeO 2 on Ce x P 1−x catalysts. Finally, reaction process study demonstrated that the NH 3 -SCR over Ce x P 1−x was processed via Langmuir-Hinshelwood (L-H) mechanism. Combining the results of active sites and reaction mechanism analysis, it was drawn that the superior low temperature activity of Ce x P 1−x could be attributed to its excellent redox properties, which promoted the oxidation of NO then facilitated the process of NH 3 -SCR via “fast SCR”.