BiOBr/g-C_3N_4纳米薄片复合光催化剂的制备及性能

Preparation and Property of BiOBr/g-C_3N_4 Nanosheets Composite Photocatalyst

用化学剥离法处理石墨相氮化碳制得纳米薄片,在超声条件下与BiOBr复合制备得到BiOBr/g-C_3N_4(CNBi)复合光催化剂.采用X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、紫外可见漫反射光谱(UV-vis)等测试手段对该光催化剂进行了表征和分析;以甲基橙为模拟污染物,评价样品的可见光(λ>420nm)催化性能.XRD和TEM结果显示,经浓硫酸处理后g-C_3N_4被剥离为纳米薄片,并且与BiOBr成功复合形成纳米异质结.UV-vis结果显示,CNBi样品的吸收边为425nm(禁带宽度约为2.93eV),介于BiOBr和g-C_3N_4纳米薄片之间.光催化试验结果表明,与单纯的BiOBr和g-C_3N_4纳米薄片相比,CNBi复合光催化剂具有更高的催化活性,BiOBr含量为30%的催化剂在2h内对甲基橙的降解效率接近100%.

A BiOBr/g-C3N4 （CNBi） composite photocatalyst was prepared by the chemically exfoliated graphite carbon nitride （g-C3N4） nanosheets under ultrasonic condition. The prepared samples were characterized by X-ray diffraction （XRD）, transmission electronic microscope （TEM）, scanning electronic microscope （SEM）, UV-vis absorption spectra （UV-vis） and other test methods. The photocatalytic activities of the samples under the visible light irradiation（λ〉420 nm）were evaluated by removal of methyl orange （MO）. Characterization results of the XRD and TEM indicated that exfoliated g-C3N4 nanosheets played important roles to generate the nano-heterojunction composite of CNBi. UV- vis results showed that the absorption edge of CNBi sample was 425 nm （about 2.93 eV）, and between BiOBr and g-C3N4. The photocatalytic results exhibited enhanced photocatalytic activity as compared to pure BiOBr and g-C3N4 nanosheets alone. To optimum methyl orange degradation （100%） was achieved by 30% loading of BiOBr photocatalyst about 2 h.