LaAl0.5Ni0.5O3钙钛矿的制备及其对甲烷干重整的催化性能

The Preparation of LaAl0.5Ni0.5O3 Perovskite and Its Catalytic Performance in Methane Dry Reforming

  • 摘要: 采用硬模板法制备比表面积大的介孔LaAl1-xNixO3钙钛矿催化剂,将其用于碳中和甲烷干重整领域,研究不同温度下的反应活性。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、N2吸附-脱附(BET)、H2程序升温还原(H2-TPR)、热重分析(TGA)对制备的催化剂进行表征。结果表明:LaAl0.5Ni0.5O3催化剂在反应过程中表现出了最优异的活性与稳定性。在反应温度为750 ℃,空速GHSV=36 000 mL/(g·h)的反应条件下, CH4与CO2的转化率分别达到69.8%和81.5%,经25 h稳定性测试后CH4与CO2的转化率仅分别降低2.7%和3.3%。这是由于在H2-Ar混合气还原过程中,LaAl0.5Ni0.5O3催化剂获得了比LaAl0.7Ni0.3O3催化剂更多的Ni活性位点,同时获得了比LaAl0.3Ni0.7O3催化剂更优异的抗烧结、抗积碳性能。

     

    Abstract: The hard template method was used to prepare the mesoporous LaAl1-xAlxO3 perovskite catalyst with a large surface area, which was used for carbon-neutral methane dry reforming for reaction activity test at different temperatures. With scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), N2 adsorption and desorption (BET), H2 temperature programmed reduction (H2-TPR), thermogravimetric analysis (TGA) and other methods, the as-prepared catalyst was characterized. The results showed that the LaAl0.5Ni0.5O3 catalyst exhibited the most excellent activity and stability during the reaction, the initial activity of CH4 and CO2 in the LaAl0.5Ni0.5O3 catalyst reached 69.8% and 81.5% respectively under the conditions of reaction temperature of 750 ℃ and space velocity GHSV=36 000 mL/(g·h). And the CH4 and CO2 activity of the LaAl0.5Ni0.5O3 catalyst reduced by 2.7% and 3.3% respectively after the 25 h stability test. The reason was that the LaAl0.5Ni0.5O3 catalyst obtained more Ni active sites than the LaAl0.7Ni0.3O3 catalyst and the LaAl0.5Ni0.5O3 catalyst had more favorable anti-sintering and anti-carbon deposition ability than the LaAl0.3Ni0.7O3 catalyst.

     

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