微波水热时间对BiVO_4微晶相组成及显微结构的影响

Influences of reaction time on the phase and microstructure of BiVO_4 microcrystallites prepared by microwave hydrothermal method

以NH4VO3和Bi(NO3)3.5H2O等为起始原料,采用微波水热法可控制备了BiVO4微晶。利用X-射线衍射仪(XRD)、扫面电子显微镜(SEM)分别对产物的物相和形貌进行了表征.结果表明:在微波水热条件下,反应温度160℃时,反应30min即可制备纯的单斜相Bi-VO4微晶.随着反应时间的延长,产物由四方相向单斜相逐渐转变,产物的结晶性逐渐提高,同时由棒状微晶逐渐变成为球状微晶.

BiVO4 microcrystallines with controllable morphologies were prepared by micro- wave hydrothermal method using NH4VO3 and Bi（NO3）3 · 5H2O as raw materials. The phase and morphology of as-prepared samples were characterized by X-Ray Diffraction （XRD）, Scanning Electron Microscope （SEM）. Resuhs indicate that the pure monoclinic Bi- VO4 microcrystallites can be obtained by a microwave hydrothermal method at 160 ~C within 30 minutes. As the reaction time increases, the crystallinity of products were found increas- ing with phase transition from Tetragonal to monoclinic BiVO4 structure. Correspondingly, the rod-like morphology changes to spherical structure as the hydrothermal time increasing.