Paraguay-Delgado F, Verde Y, Cizniega E, Lumbreras J A, Alonso-Nuñez G
Centro de Investigación en Materiales Avanzados S. C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, C.P 31109. Chih., México.
J Nanosci Nanotechnol. 2008 Dec;8(12):6445-50.
The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 degrees C of annealing. The material was synthesized using a hydrothermal method. The precursor was prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 degrees C for 48 h. The resultant material was washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.
本研究报告了纳米结构多孔混合氧化物（MoO₃-WO₃）在550℃和900℃退火时的合成方法、微观结构表征及热稳定性。该材料采用水热法合成。前驱体通过使用七钼酸铵和偏钨酸铵的水溶液制备，Mo/W原子比为1。将pH值调节至5，然后将溶液转移至内衬聚四氟乙烯的不锈钢高压釜中，在200℃下加热48小时。所得材料用去离子水洗涤。通过N₂物理吸附、扫描电子显微镜（SEM）、分析型透射电子显微镜（TEM）和X射线衍射（XRD）研究了退火前后材料的比表面积、形态、组成和微观结构。最初合成的材料显示出低结晶度和较高的比表面积（约141 m²/g）。热退火后，材料显示出更高的结晶度，其比表面积急剧减小。
