关键词: 稀土, 双层钙钛矿化合物, 单层钙钛矿化合物, 甲烷催化燃烧, 溶胶-凝胶法

Abstract: A novel rare-earth double perovskite-type catalyst La2CuMnO6 was prepared  by the sol-gel method using citric acid as a complex agent. The catalytic activity of the sample toward methane combustion was evaluated. The catalyst was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, magnetic properties, H2-temperature-programmed reduction, Scanning electron microscopy and X-ray photoelectron spectroscopy. The results show that La2CuMnO6 forms a single-phase double perovskite-type oxide by the sol-gel method at 1100 ℃ under air atmosphere for 3 h. The La2CuMnO6  reveals good catalytic activity for methane combustion. It shows light off temperature T10 of 437.5 ℃ and T90 of 649.2 ℃. Compared with the single perovskite-type oxide LaMnO3 which always was made for methane combustion catalyst, the lower light-off temperature T10 decreases 53.1 ℃ and total conversion T90 decreases 116.5 ℃, respectively. The results of FTIR show that the synthesized oxides all possess perovskite-type structures. The results of H2-TPR indicate that an increasing in the oxygen mobility existe in La2CuMnO6.  Furthermore, the SEM, TEM and the magnetic properties results also testified that, the two catalysts have different surface feature and magnetic property, In addition, XPS shows that La2CuMnO6 have more oxygen vacancies than LaMnO3. These results are in the accord with methane catalytic combustion.

Key words: Rare earth, Double perovskite-type oxide, Single perovskite-type oxide, Methane catalytic combustion, Sol-gel