通过相变制备多孔Nb_2O_5

Formation of Porous Niobium Pentoxide via Phase Transformation

以铌金属为"牺牲"阳极,在无隔膜电解槽中,采用电化学一步法制备了Nb2O5粉体的前驱体铌醇盐,铌醇盐直接水解得胶状沉淀,烘干后的胶状产物在不同热处理条件下产生的相变形成了多孔Nb2O5粉体。采用IR、TG-DSC、XRD、SEM分别对烘干后胶状产物及多孔Nb2O5进行表征。结果表明:无定型的Nb2O5在873K煅烧后形成2μm的球形二次颗粒,同时转变为正交晶型,而在1173K热处理后转变为单斜Nb2O5的同时,相变伴随Nb2O5球形颗粒向棒状结构的形貌变化,在颗粒颈部连接作用下,最终形成了多孔Nb2O5,孔径为250nm左右。

Niobium（Ⅴ） alkoxides were directly prepared in a undivided electrolytic cell by using niobium metal as sacrificing anode, then niobium（Ⅴ） alkoxides were directly hydrolyzed to gel-like deposits. The phase transformation of the gel-like product by heat treatments resulted in the formation of porous niobium pentoxide. IR, TG-DSC, XRD and SEM were used to characterize the structure of porous Nb205 and the gel-like products. Studies show that amorphous Nb205 secondary particles change into orthorhombic phase and form 2μm spherical particles after calcination at 873 K. While monoelinic Nb2O5 is obtained after calcination at 1 173 K, the porous Nb2O5 with pore size of about 250 nm is finally formed following the phase transformation of spherical Nb2O5 particles into rod like particles.