摘要
环境中污染物的低耗能绿色处理方法,特别是环境中重金属Cr(Ⅵ)的绿色处理方法,是近年来的热点研究领域。本文首先制备了TiO_2单晶颗粒,之后与不同量的Bi2S3进行复合,制备了Bi_2S_3/TiO_2复合光催化材料。研究了不同的Bi_2S_3复合量对所制备样品的组成、形貌、结构和光催化还原Cr(Ⅵ)性能的影响。通过XRD、SEM、TEM、DRS、SPV等方法对样品进行了表征。研究结果表明,TiO_2表面复合有棒状的Bi_2S_3,复合样品对Cr(Ⅵ)的可见光光催化还原效率明显高于纯TiO_2,其中0. 02 mol/L的Bi(NO_3)_3反应液制备的复合样品具有最高光催化还原效率。对样品催化机理研究表明,Bi_2S_3/TiO_2复合材料的带隙随着Bi2S3含量的增加而变窄,对可见光的吸收和利用效率明显提高;并且TiO_2与Bi_2S_3的复合,可以减弱光生电子和空穴的复合,从而有效地利用了光生电子,提高了样品对Cr(Ⅵ)的光催化还原效率。
Green and low energy consumption treatment of environmental pollutants,such as Cr( Ⅵ),has been a research hotspot in recent years. In this study,single crystal particle of TiO_2 was prepared,and then it was composed with different amounts of Bi_2S_3. The effect of the Bi_2S_3 amount on the Bi_2S_3/TiO_2 composed sample,such as composition,morphological structure and photocatalytic properties,were investigated. The XRD,SEM,TEM,DRS and SPV were used to characterize the sample. The test results show that the Bi_2S_3 in the composed sample was rodlike. The Bi_2S_3/TiO_2 composed sample has much higher photocatalysis efficiency than that of pure TiO_2 in the reduction of Cr( Ⅵ),especially the sample prepared with 0. 02 mol/L Bi( NO3)3 solution. The band gap of Bi_2S_3/TiO_2 composite is narrowed by the adding of Bi_2S_3,therefore,its utilization of visible light is improved. The Bi_2S_3 can recede the recombination of photogenerated electrons and holes,and this is the reason for its high photocatalysis efficiency in Cr( Ⅵ) reduction.
引文
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