增强活性的石墨烯/TiO_2复合物的制备及性能研究

The Preparation of Graphene/TiO_2 Composites with Enhanced Photocatalytic Activity

以氧化石墨烯为载体,以钛酸异丙酯为前驱体在氧化石墨烯表面沉积TiO2晶种,然后以氟钛酸铵和硼酸为主要原料,采用水热法实现一步还原氧化石墨烯和沉积TiO2制备石墨烯/TiO2复合物,同时以由单一前驱体氟钛酸铵制备的石墨烯/TiO2复合物作为对比催化剂。采用SEM、Raman、XRD、XPS、FT-IR等分析手段对两种催化剂进行了表征。结果表明,经水热反应后,氧化石墨烯可被还原为石墨烯,并且由两种钛源制备的复合物中石墨烯的被还原程度比单一钛源水解的要高,并且水解后复合催化剂的TiO2均为锐钛矿的球形颗粒,粒径约为250～300nm,在石墨烯表面附着良好。采用甲基橙为模拟底物评价两种复合催化剂的光催化活性,结果发现,采用两种钛源依次水解制备的复合物中由于石墨烯的还原度更高,其对底物甲基橙的吸附量更高,转移TiO2表面光生电子的能力更强,导致其具有更强的光催化活性。

Using graphene oxide as support and isopropyl titanate as precursor,TiO2 seed was deposited on the graphene oxide.Then using ammonium fluoride titanate and boric acid as raw materials,graphene/TiO2 was prepared with the hydrothermal method,which can restore graphene oxides to graphenes and deposite TiO2 at the same time.As control,another graphene/TiO2 was also fabricated without isopropyl titanate.The graphene/TiO2 composites were characterized by using SEM,Raman,XRD,XPS,FT-IR analyses.It shows that graphene oxide can be restored to graphene through the hydrothermal procedure,and the reduction degree of graphene oxide in the composite prepared with two titanium sources is higher than that of the composite prepared by only one titanium source.Moreover,TiO2 with the particle size of 250～300nm in the two catalysts is spherical and adheres well to the graphene sheet.Methyl orange was selected as the simulated substrate to evaluate the photocatalytic activity of the two composite catalysts.The experimental results indicate that graphene/TiO2 prepared by two titanium sources has a higher photocatalytic activity,because that the adsorbtion capacity of the graphene with higher reduction degree to the methyl orange increases and the graphene can more easily transfer and transport the photo-generated electrons.