摘要
用XPS,TEM,SEM,EPMA和AA分析研究了新鲜和报废Pd/C催化剂中活性金属Pd的价态、分散度、晶粒大小、分布深度、含量及载体活性炭的形貌。报废Pd/C催化剂和新鲜Pd/C催化剂相比,前者Pd分散度变差,晶粒长大,分布深度变浅,载体活性炭表面出现块状化和平整化。Pd的微观状态变化与活性炭的微观形貌变化关系密切。Pd/C催化剂报废的直接原因是使用过程中Pd晶粒的长大。
The various micro-states of fresh and scrapped Pd/C catalysts were studied by XPS,TEM, EPMA, AA and SEM. As compared with the fresh Pd/ C catalyst, the valence state of the scrapped Pd/C catalyst was lowered, the oxidability weakened, the dispersity decreased, the grain grew and diffused outwards and the layer containing Pd became thiner, and the background surface of carrier active carbon was blocked by many lumps and leveled. The alternation of micro-state of Pd is closely related to the change of the configuration of carrier. The scrapping of Pd/C catalyst is mainly due to the grain growing in the reaction process.
