Preparation of p-n heterojunction g-C3N4/BiOBr and its photocatalytic performance under visible light
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摘要: 以三聚氰胺作为合成g-C3N4纳米片的前躯体，以Bi（NO3）3·5H2O和KBr作为合成BiOBr的原料，采用水热法构建g-C3N4/BiOBr二维异质结可见光催化剂，有效的晶面复合和合适的能带组合有助于增强g-C3N4和BiOBr的可见光催化活性。利用X射线衍射（XRD）、透射电镜（TEM）、X射线光电子能谱（XPS）、光致发光光谱（PL）和紫外-可见漫反射光谱（UV-vis DRS）等方法表征其结构、光学性质以及组成结构。在可见光（λ>420 nm）下以光催化降解RhB来评价合成催化剂的光催化活性，结果表明，g-C3N4/BiOBr光催化降解罗丹明B（RhB）的效率高于单体g-C3N4和BiOBr，并对g-C3N4/BiOBr增强可见光催化RhB机理进行解释。
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关键词:
- g-C3N4/BiOBr /
- 异质结 /
- 降解 /
- 光催化
Abstract: g-C3N4 nanosheet was obtained from the precursors melamine and BiOBr nanosheets was synthesized from the raw materials Bi(NO3)3·5H2O and KBr. The two-dimensional g-C3N4/BiOBr heterojunction was synthesized by hydrothermal method. The intimated interface and suitable crystal facets of g-C3N4 and BiOBr were favorable the combination of this two photocatalysts, resulting in enhancing the visible-light photocatalytic activity. The phase structure, optical absorption property as well as composition and structure of as-prepared materials were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflection spectroscopy (DRS) and photoluminescence emission spectroscopy. The potential mechanisms of constructing two-dimensional g-C3N4/BiOBr heterojunction were revealed. The photocatalytic activity of as-synthesized photocatalysts was evaluated by photocatalytic degradation of RhB under visible light (λ>420 nm) irradiation. Results show that the as-synthesized heterojunctions can significantly enhance photocatalytic activity in comparison with pure g-C3N4 and BiOBr. The mechanisms of enhanced photocatalytic performance were explained.-
Key words:
- g-C3N4/BiOBr /
- heterojunction /
- degradation /
- photocatalysis
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图 3 样品50% g-C3N4/BiOBr的XPS谱图
Figure 3 XPS patterns of 50% g-C3N4/BiOBr
(a): survey; (b): C 1s; (c): N 1s; (d): O 1s; (e): Br 3d; (f): Bi 4f
图 6 样品对液相RhB的光催化降解效率
Figure 6 Photocatalytic activity of obtained samples for degradation of RhB under visible light irradiation
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