溶液pH值对PbWO_4晶相和形貌的影响

Control of PbWO_4 Crystal Phase and Morphology under Varying pH Conditions

在30℃下,以Na2WO4和Pb(NO3)2为原料,通过沉淀反应制备PbWO4晶体。考察Pb(NO3)2溶液的pH值对PbWO4的晶型和形貌的影响。通过XRD、Raman和SEM等表征,发现在酸性和碱性溶液中分别得到了梭状和八面体状的四方晶相PbWO4晶体,而在中性溶液中,得到单斜晶相PbWO4纳米带,表明pH值显著影响Pb-WO4的晶型和形貌。室温下,以300nm为激发波长研究产物的固体荧光光谱,发现碱性条件下得到的四方相Pb-WO4八面体具有最强的绿发光带,表明PbWO4的荧光性质受其晶型和形貌影响。

PbWO4 crystals are synthesized at 30℃ by the precipitation reaction of Na2WO4 and Pb（NOa）2 in an aqueous solution. The effect of the pH value of Pb（NOa）2 solution on the polymorphism and morphology of PbWO4 is investigated by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Shuttle-like and octahedron-like PbWO4 particles of tetragonal stolzite structures are obtained in acidic and basic solutions, respectively. Monoclinic raspite PbWO4 nanobelts are prepared at pH 7.0. These results indicate the strong influence of pH on the polymorphism and morphology of PbWO4. The photoluminescence properties of PbWO4 are also studied. Stolzite octahedron-like PbWO4 is found to pos-sess excellent photoluminescence.