Facile constructing plasmonic Z-scheme Au NPs/g-C3N4/BiOBr for enhanced visible light photocatalytic activity
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摘要: 通过水热和原位还原法制备了一种新型Z型异质结三元复合材料Au NPs/g-C3N4/BiOBr，并通过X射线衍射、X射线光电子能谱、透射电子显微镜、紫外-可见漫反射光谱和光致发光发射光谱等技术对材料的形貌、结构进行了表征。通过在可见光下降解苯酚来评价光催化剂的活性。研究发现，Au NPs/g-C3N4/BiOBr显示出增强的光催化活性，对苯酚的降解能力是g-C3N4的3倍，是BiOBr的2.5倍。这可归因于三元复合材料的窄带隙（2.10eV）、Z型机理对光生电子-空穴对的有效分离和Au纳米颗粒的表面等离子体共振效应（SPR）。
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关键词:
- Au NPs/g-C3N4/BiOBr /
- Z型催化剂 /
- 可见光 /
- 苯酚 /
- 等离子体
Abstract: A novel ternary Au NPs/g-C3N4/BiOBr Z-scheme heterojunction composite was fabricated through hydrothermal and in-situ reduction method, and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, ultraviolet-visible diffuse reflection spectroscopy and photoluminescence emission spectroscopy. The photocatalytic activity was evaluated by the degradation of phenol under visible-light irradiation. It was found that Au NPs/g-C3N4/BiOBr showed enhanced photocatalytic activity, which is 3-fold higher than g-C3N4 and 2.5-fold higher than BiOBr. This could be attributed to the effective separation of photogenerated electron-hole pairs, narrowed band gap (2.10 eV) and surface plasmon resonance (SPR).-
Key words:
- Au NPs/g-C3N4/BiOBr /
- Z-scheme /
- visible-light photocatlysis /
- phenol /
- plasmon
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Figure 1 TEM images of Au NPs/g-C3N4/BiOBr (a) and (b); high-resolution TEM images of the Au (c) and BiOBr particle (d) of Au NPs/g-C3N4/BiOBr; (e) EDS spectrum of Au NPs/g-C3N4/BiOBr
Figure 2 XRD patterns of pure g-C3N4, pure BiOBr, g-C3N4/BiOBr and Au NPs/g-C3N4/BiOBr
Figure 3 XPS spectra of Au NPs/g-C3N4/BiOBr (a) survey scan; (b) Au 4f; (c) C 1s; (d) N 1s; (e) Bi 4f; (f) Br 3d and (g) O 1s
Figure 4 (a) UV-vis diffused reflectance spectra; (b) plot of (αhv)1/2 versus photon energy (hv) curves of g-C3N4, BiOBr, g-C3N4/BiOBr and Au NPs/g-C3N4/BiOBr; (c) the PL spectra of pure g-C3N4, pure BiOBr, g-C3N4/BiOBr and Au NPs/g-C3N4/BiOBr
a: g-C3N4; b: BiOBr; c: g-C3N4/BiOBr; d: Au NPs/g-C3N4/BiOBr
Figure 5 (a) Photocatalytic degradation of phenol over g-C3N4, BiOBr, Au NPs/BiOBr, Au NPs/g-C3N4, g-C3N4/BiOBr and Au NPs/g-C3N4/BiOBr under visible light irradiation; (b) The rate constant (k) of as-prepared samples for photocatalytic degradation of phenol under visible light; (c) Cycling tests of Au NPs/g-C3N4/BiOBr towards the degradation of phenol
■: g-C3N4; ●: BiOBr; ▲: Au NPs/BiOBr; ▼: Au NPs/g-C3N4; ◆: g-C3N4/BiOBr; : Au NPs/g-C3N4/BiOBr
Figure 6 (a) Effects of ·OH, h+ and ·O2- quenchers on the degradation of phenol; (b) band structure alignments for g-C3N4, BiOBr, g-C3N4/BiOBr and Au NPs/g-C3N4/BiOBr
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