La0.8Sr0.2Fe1-xScxO3-δ催化剂的制备、表征及甲烷催化燃烧性能

采用甘氨酸-硝酸盐溶液燃烧法制备了钙钛矿型氧化物催化剂La_0.8Sr_0.2Fe_1-xSc_xO_3-δ (LSFS, x=0, 0.3,0.4, 0.5, 0.6, 0.8, 1), 利用X射线衍射(XRD)、H₂程序升温还原(H₂-TPR)、扫描电子显微镜(SEM)和比表面积测试等手段对催化剂进行了系统表征, 并在常压微型固定床反应器上考察了催化剂对甲烷燃烧的催化性能. 结果表明, 经空气气氛下900 °C煅烧5 h制备的LSFS均具有单一的钙钛矿结构, 在La_0.8Sr_0.2FeO_3-δ (LSF)中掺杂Sc有助于改善催化剂的抗烧结性能, 提高催化剂的比表面积. 当LSF 中的Sc 掺杂量为0.4-0.6 时, 所形成的LSFS表现出良好的甲烷催化燃烧活性, 其中Sc 掺杂量为0.5 时, 其起燃温度(T₁₀)和完全转化温度(T₉₀)分别为406和563 °C, 与La_0.8Sr_0.2FeO_3-δ和La_0.8Sr_0.2ScO_3-δ相比, T₁₀分别降低了14和87 °C; T₉₀分别降低了59和95 °C.

Preparation,Characterization and Catalytic Activities of La0.8Sr0.2Fe1-xScxO3-δ Catalysts for Methane Combustion

Perovskite-type La_0.8Sr_0.2Fe_1-xSc_xO_3-δ (LSFS, x=0, 0.3, 0.4, 0.5, 0.6, 0.8, 1) catalysts were prepared by glycine-nitrate solution combustion. The catalysts were characterized by X-ray powder diffraction (XRD), H₂-temperature-programmed reduction (H₂-TPR), scanning electron microscopy (SEM), and specific surface area measurements. The catalytic performance of LSFS for methane combustion was investigated in a micro fixed-bed reactor. The results showed that all the LSFS catalysts have a single perovskite structure after calcining in air at 900 °C for 5 h. By doping Sc into La_0.8Sr_0.2FeO_3-δ, the sintering agglomeration between the LSFS particles is weakened, and therefore the specific surface area is increased. At Sc dopings of 0.4-0.6, the resultant LSFS gives good catalytic activity for methane combustion, with a light-off temperature (T₁₀) of 406 °C and a total conversion temperature (T₉₀) of 563 °C at a Sc doping of 0.5. Compared with La_0.8Sr_0.2FeO_3-δ and La_0.8Sr_0.2ScO_3-δ the T₁₀ is decreased by 14 and 87 °C, and T₉₀ is decreased by 59 and 95 °C, respectively.