Tween80对微波水热法制备BiFeO3粉体的影响

Effect of Tween 80 on Preparation of BiFeO_3 in Microwave-Hydrothermal Method

以Bi(NO3)3.5H2O和FeCl3.6H2O为原料、KOH为矿化剂、Tween 80为表面活性剂,采用微波水热法合成BiFeO3粉体。研究了Tween 80含量对BiFeO3粉体形貌、物相及光催化性能的影响,结果表明:在200℃保温1 h,KOH浓度为1.5 mol/L、Tween 80加入体积分数为0～1.7%、Fe与Bi摩尔比为1.0时,合成出单相BiFeO3粉体。当Tween 80加入量小于1.7%时,随Tween 80加入量增加,BiFeO3粉体形貌逐渐变为均匀的毛球状,以此时的粉体作催化剂时,紫外光照射4 h后罗丹明B的降解率从48.92%上升到79.71%;当Tween 80加入量大于1.7%时,制备出BiFeO3–Bi25FeO40复合粉体,以BiFeO3–Bi25FeO40复合粉体、BiFeO3和Bi25FeO40简单混合的粉体作催化剂,紫外光照射4 h后罗丹明B的降解率分别为97.42%与86.73%。以BiFeO3粉体、一次回收的BiFeO3粉体和二次回收的BiFeO3粉体作催化剂时,经紫外光照射4 h后罗丹明B的降解率分别为79.71%、76.78%和68.84%。

The pure phase of BiFeO3 powder was synthesized by a microwave-hydrothermal method with FeCl3·6H2O and Bi（NO3）3·5H2O powder as raw materials,KOH as mineralizer and Tween 80 as a surfactant.The effects of the amount of Tween 80 on morphology,phase composition and photocatalytic property of BiFeO3 powder were investigated.The results indicate that the single phase of BiFeO3 powder could be prepared via the microwave-hydrothermal method at 200 ℃ for 1 h with KOH of 1.5 mol/L,the volume fraction of Tween 80 of 0–1.7% and a mole ratio of Fe to Bi of 1.0.Morphology of the BiFeO3 powder became uniform hair ball-like when volume fraction of Tween 80 was less than 1.7%.When the hair ball-like BiFeO3 powder was used as a catalyst,deg-radation rate of Rhodamine B increased from 48.92% to 79.71% after 4 h UV light irradiation.The BiFeO3–Bi25FeO40 composite powder was prepared when volume fraction of the Tween 80 was higher than 1.7%.When the BiFeO3–Bi25FeO40 composite powder or the mixture of BiFeO3 and Bi25FeO40 powders were used as catalyst,degradation rates of Rhodamine B after 4 h UV light irradia-tion were 97.42% and 86.73%,respectively.When the BiFeO3 powder,the first reclaimation BiFeO3 powder or the second reclaima-tion BiFeO3 powder were used as catalyst,degradation rates of Rhodamine B after 4 h UV light irradiation were 79.71%,76.78% and 68.84%,respectively.