Abstract:

Graphene(GR) and titanium dioxide/graphene oxide(TiO₂/GO) composite are prepared by the Hummers method modified by acid dialysis and sol-gel method, respectively. The synthesized TiO₂/GR composite is characterized by SEM, XRD and FTIR, respectively. The photocatalytic reduction of Cr(Ⅵ) in water is studied under simulated sunlight, and the corresponding mechanism is discussed. The results show that the addition of GO can not only maintain the crystal type of TiO₂ anatase but also can effectively inhibit the aggregation of the composite. Furthermore, the structure of TiO₂/GR is stable after calcination. In the photocatalytic process, GR can increase the adsorption amount of the Cr(Ⅵ) on the surface of catalyst and then enhance the photocatalytic reduction. The reduction rate of 30 mg/L Cr(Ⅵ) reaches 84% after 120 min of reaction time. It is also proved that adding EDTA-2Na into the reaction system and isolating air are beneficial to the photocatalytic reduction of Cr(Ⅵ).

Key words: titanium dioxide, graphene, photocatalysis, sunlight, chromium

摘要：

采用酸渗析改进Hummers法制备石墨烯（GR），并用溶胶-凝胶法制备了TiO₂/GR复合材料。采用SEM、XRD、FTIR对制得TiO₂/GR进行表征，在模拟太阳光下研究水中Cr（Ⅵ）的光催化还原去除，并探讨了太阳光下Cr（Ⅵ）光催化还原的机理。结果显示，GR的加入不会改变TiO₂锐钛矿晶型结构，还能有效抑制TiO₂颗粒的团聚，煅烧后的TiO₂/GR结构稳定。在光催化过程中，GR能提高Cr（Ⅵ）在催化剂表面的吸附量，从而促进Cr（Ⅵ）的光催化还原，30 mg/L Cr（Ⅵ）溶液经过120 min光照后还原率可达84%。在反应体系中加入空穴清除剂EDTA-2Na并隔绝空气均有利于Cr（Ⅵ）光催化还原反应的进行。

关键词: 二氧化钛, 石墨烯, 光催化, 太阳光, 铬

CLC Number: 

• X703