Ru 前驱体对 Ru/MgO-CeO2 氨合成催化剂性能的影响

 分别以 K₂RuO₄, Ru(Ac)₃ 和 RuCl₃ 为 Ru 前驱体, 制备了 Ru/MgO-CeO₂ 催化剂, 并运用 X 射线衍射、X 射线荧光光谱, CO 吸附、N₂ 物理吸附和 H₂程序升温还原等技术对催化剂进行了表征, 考察了 Ru 前驱体对 Ru/MgO-CeO₂ 催化剂氨合成性能的影响. 结果表明, Ru 前驱体对载体 MgO-CeO₂ 和 Ru 的还原性能、氯残留量和催化剂比表面积的影响都很大, 从而导致催化剂的氨合成性能的不同. 其中以 K₂RuO₄ 为 Ru 前驱体制备的催化剂的载体和 Ru 容易还原, 无氯离子, 且比表面积较高, 因而催化剂活性和氨合成转换频率较高. 在 10 MPa, 425 °C, 10 000 h^-1 条件下, K₂RuO₄, Ru(Ac)₃ 和 RuCl₃ 作前驱体制备的催化剂上氨合成转换频率比为 1.33:1.05:1.

Effect of Precursors on Catalytic Activity of Ru/MgO-CeO2 Catalyst for Ammonia Synthesis

Ru/MgO-CeO₂ catalysts were prepared by co-precipitation with different precursors, including K₂RuO₄, Ru(Ac)₃, and RuCl₃, the obtained catalysts were characterized by X-ray diffraction, X-ray fluorescence, N₂ physisorption, temperature-programmed reduction, and CO chemisorption. The results showed that the ammonia synthesis activity of the Ru/MgO-CeO₂ catalyst prepared with K₂RuO₄ was 16.0% at 10 MPa, 450 °C, and 10 000 h^-1, which was higher than those obtained with the other two precursors. The turnover frequency (TOF) of the Ru/MgO-CeO₂ catalyst prepared with K₂RuO₄ was higher than those obtained with the other precursors under the same reaction conditions. The influence of precursors and preparation methods on the structure and performance of the catalysts was studied. The ratio of Ru/MgO-CeO₂ catalysts prepared with K₂RuO₄, Ru(Ac)₃, and RuCl₃ as precursors for ammonia synthesis turnover frequency is 1.33:1.05:1 under 10 MPa, 425 °C, and 10 000 h^-1.