Porous lanthanide oxides were fabricated by a precursor-thermolysis method. The precursors were synthesized by a hydrothermal reaction with lanthanide (La, Ce, Pr and Nd) salts, sodium oxalate and asparagine (or glutamine). Under hydrothermal conditions asparagine and glutamine exhibited greatly different complexation abilities with lanthanide cations. The competitive interactions of lanthanide cations with oxalate anions and asparagine (or glutamine) gave rise to the formation of precursors with different structures and morphologies. ESI-MS detection further confirmed the different complexation abilities of asparagine or glutamine with lanthanide cations at the molecular level. Variation of oxalate anion concentration or the pH value of the reaction solution could tune the morphology of the products. After calcination, porous lanthanide oxides were obtained with the morphologies of their corresponding precursors. Our work suggests that the complexation ability of organic molecules with metal cations could be a crucial factor for morphological control of the precursors. Moreover, considering the diversity of organic additives and metal salts, other metal oxides with complex composition and morphology could be fabricated via this organic molecule-modified precursor method.
多孔
镧系氧化物是通过前驱体-热解法制造的。前驱体是通过与
镧系元素(La、Ce、Pr 和 Nd)盐、
草酸钠和天冬酰胺(或谷
氨酰胺)进行
水热反应合成的。在
水热条件下,天冬酰胺和谷
氨酰胺与
镧系阳离子的络合能力大不相同。
镧系阳离子与
草酸阴离子和天冬酰胺(或谷
氨酰胺)之间的竞争性相互作用形成了具有不同结构和形态的前体。ESI-MS 检测进一步证实了天冬酰胺或谷
氨酰胺与
镧系阳离子在分子
水平上的不同络合能力。
草酸盐阴离子浓度或反应溶液 pH 值的变化可调节产物的形态。煅烧后得到的多孔
镧系元素氧化物具有相应前体的形态。我们的工作表明,有机分子与
金属阳离子的络合能力可能是控制前驱体形态的关键因素。此外,考虑到有机添加剂和
金属盐的多样性,通过这种有机分子修饰前驱体的方法还可以制备出其他具有复杂组成和形态的金属氧化物。