高岭土/SnO_2/Sn^(2+)的制备及其光催化性能

Preparation and photocatalytic properties of kaolin clay/SnO_2: Sn^(2+) photocatalyst

二氧化锡(Sn O_2)具有优异的光电性质,但因为其禁带宽为3.6 e V,对可见光无响应。为拓宽Sn O_2对光的响应范围,对其进行了改性研究。本文利用水热法制备了不同掺杂比例的高岭土/Sn O_2/Sn^(2+),利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、紫外可见漫反射(UV-vis)对光催化剂形貌及特性表征分析。结果显示,高岭土/Sn O_2/Sn^(2+)降低Sn O_2的禁带宽带,4%高岭土/Sn O_2/Sn^(2+)的禁带宽度最小,为2.62 e V。利用氙灯模拟太阳光,在500 W氙灯照射条件下,4%高岭土/Sn O_2/Sn^(2+)降解甲基橙的效果最佳,光反应120 min,50 mg光催化剂对10 mg/L甲基橙的降解率达到了98%;分析了不同光催化剂含量和不同甲基橙浓度对光催化影响,发现光催化剂含量的改变比甲基橙浓度的改变对光催化剂降解甲基橙的影响更明显,其中50 mg 4%高岭土/Sn O_2/Sn^(2+)光催化剂在降解20 mg/L的甲基橙溶液时候表现出较高的效率,120 min降解了55%。

Tin oxide(SnO 2)has excellent photoelectronic properties,however,it is not responsive to visible light because of its wide band gap(3.6 eV).To widen its light responsive range,modification of SnO 2 was conducted.In this study,kaolin clay/SnO 2/Sn 2+was synthesized via hydrothermal method,and the morphology and photocatalytic properties were characterized using XRD,SEM,TEM and UV-vis DRS.Results showed that the band gap of kaolin clay/SnO 2/Sn 2+was lower than that of the pure SnO 2,and the 4%kaolin clay/SnO 2/Sn 2+has the lowest band gap(2.62 eV).Xenon lamp was used to simulate the sun light,and clay/SnO 2/Sn 2+has the optimal photocatalytic activity in degrading methyl orange under 500W xenon lamp irradiation.The degradation efficiency of 10mg/L methyl orange reached 98%within 120 minutes with the presence of 50mg dosage of photocatalyst.Meanwhile,the effects of the photocatalyst dosage and initial methyl orange concentration on the photocatalytic performance were studied.It was found that the photocatalyst dosage has greater effect on the degrading process than the initial concentration of methyl orange.Dosage of 50mg 4%kaolin clay/SnO 2/Sn 2+was of high efficiency in degradation of 20mg/L methyl orange,and the efficiency reached 55%.