Z型光催化剂 – 化学慧

Z型石墨C₃N₄/还原TiO₂微球光催化材料

Construction of hybrid Z-scheme graphitic C₃N₄/reduced TiO₂ microspherewith visible-light-driven photocatalytic activity

在可见光驱动下具有光催化活性的杂化Z型石墨C₃N₄/还原TiO₂微球的构建

Authors: C. Zhou, N.F. Ye, X.H. Yan*, J.J. Wang, J.M. Pan, D.F. Wang, Q. Wang, J.X. Zu and X.N. Cheng

Volume 4, Issue 3, Pages 238-246

A novel Z-scheme graphitic C₃N₄/reduced TiO₂ microsphere (g-C₃N₄/r-TiO₂) has been successfully synthesized by a solvothermal method. The as-prepared samples with different contents of g-C₃N₄ were characterized by X-ray diffraction, electron paramagnetic resonance, scanning electron microscope, UV–vis. diffuse reflectance and photoluminescence spectra.

本实验中，采用了溶剂热法成功合成了一种新型Z型石墨C₃N₄/还原TiO₂微球（g-C₃N₄/r-TiO₂），并通过X射线衍射、电子顺磁共振、扫描电子显微镜、紫外-可见光反射光谱以及光致发光光谱对制备得到的不同g-C₃N₄含量的样品进行了表征。

The r-TiO₂ microspheres are aggregated on the surface of g-C₃N₄ sheets in the as-prepared g-C₃N₄/r-TiO₂ composites.

在制备得到的g-C₃N₄/r-TiO₂复合材料中，r-TiO₂微球聚集分布在g-C₃N₄片层的表面。

All g-C₃N₄/r-TiO₂ catalysts show enhanced photocatalytic activity for the degradation of rhodamine B under visible light irradiation. It could be attributed to these influences of oxygen vacancy (changing the band gap of TiO₂), the large specific surface area (providing much more active sites for photocatalytic reaction), and the synergetic effect between g-C₃N₄ and r-TiO₂ (promoting the separation for photoinduced electron-hole pairs).

所有g-C₃N₄/ r-TiO₂催化剂在可见光照射下降解罗丹明B的光催化活性都得到了增强。催化活性的增强归功于氧空位的影响（改变了TiO₂的带隙），大的比表面积（为光催化反应提供更多的活性位点）以及g-C₃N₄和r-TiO₂之间的协同作用（促进光致电子-空穴对的分离）。

Moreover, the Z-scheme carriers transfer mechanism in the photocatalytic process has been discussed through trapping experiments of active species.

此外，通过活性物质的捕获实验，文章也讨论了在光催化过程中Z型载流子传输的机制。

The work demonstrates the strategies of the construction of Z-scheme carriers transfer system, the introduction of oxygen vacancy and structure designing are beneficial to design materials toward solar energy conversion like contaminant degradation.

本工作论证了Z型载流子传递系统的构建策略。氧空位的引入和结构设计也有利于构建太阳能转化材料，如污染物降解材料等。

文中部分图片：

物相和成分分析

Fig. 2. XRD patterns of g-C₃N₄, r-TiO₂ and g-C₃N₄/r-TiO₂ composites (a), TG curves of r-TiO₂, g-C₃N₄ (insert) and g-C₃N₄/r-TiO₂ photocatalysts in air (b), EPR spectrum of 15% g-C₃N₄/r-TiO₂ (c), FTIR spectra of TiO₂ (insert), g-C₃N₄ and 15% g-C₃N₄/r-TiO₂ composite (d).

孔径分布

Fig. 5. Nitrogen adsorption-desorption of 15% g-C₃N₄/r-TiO₂ and pore size distribution curves (insert)

光学性能

Fig. 6. UV–vis. DRS spectra of the samples (a), The band gap of samples (b), The photoluminescence spectra of g-C₃N₄, r-TiO₂ and g-C₃N₄/r-TiO₂ composites (c), EIS for 15% g-C₃N₄/r-TiO₂ and r-TiO₂ (d).

光催化降解罗丹明B

Fig. 4. (a) Height image; (b) ESM amplitude images with a −1 V DC voltage applying to the ESM tip; (c) ESM amplitude images with a 1 V DC voltage applying to the ESM tip; and (d) I-V curve of VO₂ obtained by c-AFM.

循环使用性能

Fig. 5. (a) Current image with a sample voltage of 3 V; prior to the scanning with 3 V, the areas in the white dashed boxes are poled with corresponding voltages; (b) images of deflection and current with sample voltages of 10 V and −10 V, respectively.

光催化机理

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这篇妙文是由江苏大学严学华教授带领的团队所创作，可谓是条理清晰、层层递进。严教授也担任了《硅酸盐学报》的审稿人，为《学报》刊登论文质量保驾护航。让我们来认识下敬业的严教授！

Prof. Dr. Xuehua Yan: a Professor in School of Materials Science and Engineering, Jiangsu University, China. He got his Ph.D. in 2006 from Jiangsu University, worked in Technical University of Darmstadt (Germany) in 2008 as a visiting Professor and collaborated with Prof. Dr. Ralf Riedel. His research focuses on functional inorganic materials and composites, including photocatalytic nanomaterials, energy storage materials and porous materials. He has published 120 peer-reviewed papers and hold 16 national patents. He is a member of the editorial committee of Journal of the Chinese Ceramic Society.