Influence of lattice oxygen on properties of Ce–Fe composite in NO+CO reduction system

Ce–Fe composite was prepared by hydrothermal method to simulate the ore facies with Ce–Fe coatingembedded structure in rare earth tailings. Fe₂O₃ is used as the carrier and cerium nitrate is used as active component. We studied the effect of lattice oxygen on the performance of Ce–Fe composites in the NO+CO reduction system. The results show that the peak of CeO₂ in the sample prepared by the hydrothermal method of nitric acid moves at a high angle, the lattice constant becomes smaller, and the diffraction peak corresponding to CeO₂ in Raman is red-shifted. It indicated that the hydrothermal method can form Ce–O–Fe solid solution. In TEM, nanoscale Fe₂O₃ particles caused by the decomposition of ferric nitrate were observed on the surface of the sample. In the whole reaction process, a large amount of lattice oxygen provided by Fe₂O₃ as a carrier, the presence of Ce–O–Fe solid solution and free Fe₂O₃ fine particles determine the high catalytic activity of the composite catalyst. The presence of CeO₂ can improve the surface reduction of Fe₂O₃, and also promote the conversion of Fe³⁺ to Fe²⁺, Ce⁴⁺ to Ce³⁺. The conversion of lattice oxygen to adsorbed oxygen reflects the combined action of the composite catalysts Ce and Fe. The denitration rate of the Ce–Fe composite NO+CO reduction system exceeded 92.24% at 700 °C. Lattice oxygen can promote the performance of Ce–Fe composites in NO+CO reduction system.