反应时间对钨酸铋材料形貌及其可见光催化性能的影响

Effect of Reaction Time on the Morphology and Visible-light Photocatalytic Property of Bismuth Tungstate

采用水热法在不同反应时间下制备了钨酸铋(Bi2WO6)碟状结构的光催化剂,对Bi2WO6的晶体结构、组成成分、形貌、光吸收特性和可见光催化活性等进行了表征。结果表明,反应时间影响Bi2WO6样品的形貌。水热反应6 h时,Bi2WO6样品处于非晶态,随着反应时间的增加,Bi2WO6由二维盘状结构逐渐堆积成三维碟状结构,水热反应48 h后可形成完整的微米碟。180℃水热反应48 h后制备出的Bi2WO6纳米材料具有较高的羟基自由基生成速率和较强的可见光催化活性,反应时间过长或者过短都不利于Bi2WO6可见光催化性能的提高。同时分析了不同Bi2WO6样品的可见光催化效率存在差异的原因,并且提出了不同反应时间下Bi2WO6材料的微观生长机理。

The bismuth tungstate（Bi2WO6） samples with micro-dish morphologies were synthesized by a simple hydrothermal method for different reaction time.The crystal structure,compositions,morphology,morphology,optical absorption property and photocatalytic activities of the samples were characterized.The results indicate that the hydrothermal time played a key role in the morphology of Bi2WO6.The sample was poorly crystallized after 6 h of the hydrothermal process.As the hydrothermal time increasing,the morphologies of Bi2WO6were transformed from a two-dimensional plate-like structure to a threedimensional dish-like structure.After 48 h of the hydrothermal reaction,a microstructured dish-like shape was completely formed.The Bi2WO6synthesized at 180 ℃ for 48 h had higher ·OH formation rate and better visible-light-driven photocatalytic activity.Neither longer nor shorter reacting time can improve the photocatalytic performance of Bi2WO6.Moreover,the formation mechanisms of Bi2WO6under different hydrothermal time were investigated.