铈酸钡和钇掺杂的铈酸钡复合氧化物的制备及其在钌基氨合成催化剂中的应用

 采用柠檬酸法合成了 BaCeO3 和掺杂 Y3+的 BaCe0.9Y0.1O3-δ 复合氧化物, 以 Ru3(CO)12 为前体, 利用浸渍法制备了 Ru/BaCeO3 和 Ru/BaCe0.9Y0.1O3-δ 催化剂. 通过 X 射线衍射、扫描电镜和透射电镜技术对样品进行了表征, 并在固定床反应器中考察了催化剂的氨合成反应活性. 结果表明, 载体 BaCeO3 的稳定性优于 BaCe0.9Y0.1O3-δ, 但 Ru/BaCe0.9Y0.1O3-δ 催化剂的氨合成活性明显高于 Ru/BaCeO3, 在 3.0 MPa, 15 000 h?1, 425 oC 反应时, Ru/BaCe0.9Y0.1O3-δ 催化剂上氨合成反应速率达到 432.5 ml/(g?h), 是 Ru/BaCeO3 催化剂的 1.6 倍. 这种活性和稳定性的显著差异来自载体中 Ce4+ 与 Ru 纳米粒子间的电子作用.

Preparation and Catalytic Properties of Barium Cerate and Yttrium-Doped Barium Cerate Supported Ruthenium for Ammonia Synthesis

Barium cerate (BaCeO_3) and yttrium-doped barium cerate (BaCe_(0.9)Y_(0.1)O_(3-δ) were synthesized by the citric acid method and used as supports for Ru/BaCeO_3 and Ru/BaCe_(0.9)Y_(0.1)O_(3-δ) catalysts prepared by incipient wetness impregnation using Ru_3(CO)_(12) as precursor. The supports and catalysts were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Their catalytic properties for ammonia synthesis were evaluated in a fixed-bed reactor. The stability of BaCeO_3 was superior to that of BaCe_(0.9)Y_(0.1)0_(3-δ), and the catalytic activity of Ru/BaCe_(0.9)Y_(0.1)O_(3-δ) was higher than that of Ru/BaCeO_3. The rate of ammonia synthesis over Ru/BaCe_(0.9)Y_(0.1)0_(3-δ) was 432.5 ml/(g·h)at 3.0 MPa, 425 ℃, and 15 000 h~(-1), which was 1.6 times higher than that of Ru/BaCeO_3. The electronic interaction between Ce~(4+) and Ru nanoparticles was the key factor for the difference in catalytic activity and stability.