| 硝酸活化三聚氰胺前驱体对g-C3N4结构和可见光催化性能的影响 |
| Effect of Nitric Acid Activation Melamine Precursor on Structure and Visible-Light Photocatalytic Performance of g-C3N4 |
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| 摘要: 为缩短e-和h+的迁移途径而改善g-C3N4易发生光生载流子复合的缺陷，采用不同物质的量浓度的HNO3活化三聚氰胺前驱体，通过形成质子化氨基基团，制备了一系列x-HNO3-g-C3N4（x=1，2，3，4，5 mol·L-1）光催化剂。采用N2物理吸附-脱附、X射线粉末衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、X射线光电子能谱（XPS）、荧光光谱（PL）、紫外-可见漫反射光谱（UV-Vis DRS）、瞬态光电流响应谱（TCS）和电化学阻抗图谱（EIS）等测试手段对上述光催化剂进行了表征分析，以考察催化剂的结构与其光催化性能之间的影响作用规律。以罗丹明B（RhB）为模拟染料污染物，分别以x-HNO3-g-C3N4和直接煅烧三聚氰胺得到的g-C3N4为光催化剂，进行了可见光催化降解活性差异性能测试研究。由实验结果可知：3 mol·L-1-HNO3-g-C3N4的光催化活性最高，相较于直接煅烧三聚氰胺得到的g-C3N4，在60 min内，其可将RhB的降解率从38%提高到99%。将3 mol·L-1-HNO3-g-C3N4催化剂循环使用4次后，催化效果仍为99%。这是因为三聚氰胺前驱体经HNO3活化后，可使经热聚合制备而成的g-C3N4产品具有较高的聚合度，从而得到具有大比表面积的多层g-C3N4；此外，PL结果证明其荧光强度明显降低，而使载流子寿命获得了显著提高；EIS结果表明其载流子传输能力有了明显的增强，从而提高了g-C3N4的光催化活性。 |
| 关键词: 三聚氰胺 g-C3N4 光催化 稳定性 可见光 |
| 基金项目: 国家自然科学基金资助项目（No.21766009）和江西理工大学清江青年英才支持计划资助 |
| Abstract: In order to shorten the migration pathway of e- and h+ and improve the defect of recombination of photo-generated carriers in g-C3N4, this study used different molar concentrations of HNO3 to activate melamine precursor, and formed a series of x-HNO3-g-C3N4 (x=1, 2, 3, 4, 5 mol·L-1) photocatalyst by forming a protonated amino group. In order to investigate the effect of the structure of the catalyst on its photocatalytic properties, all these above obtained photocatalysts were characterized by nitrogen gas adsorption-desorption isotherms, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), photoluminescence (PL), ultraviolet-visible diffuse reflection (UV-Vis DRS), transient photocurrent spectroscopy (TCS), electrochemical impedance spectroscopy (EIS), etc. The difference of visible light catalytic degradation activity of x-HNO3-g-C3N4 and g-C3N4 obtained by direct calcination of melamine was studied with the using of rhodamine B (RhB) as a simulated dye contaminant. The resuts of experimental showed that the photocatalytic activity of 3 mol·L-1-HNO3-g-C3N4 was the highest. Compared with g-C3N4 obtained by directly calcining melamine, the degradation rate of RhB increased from 38% to 99% within 60 minutes. The 3 mol·L-1-HNO3-g-C3N4 catalyst was recycled 4 times, and the catalytic effect was still 99%. The high catalytic activity and stability of x-HNO3-g-C3N4 can be explained as follows:after activation of HNO3, the melamine precursor can make the g-C3N4 product prepared by thermal polymerization have a higher degree of polymerization, thereby a multi-layer g-C3N4 with large specific surface area was obtained. The PL results showed that the fluorescence intensity was significantly reduced, and the carrier lifetime was significantly improved. The EIS results showed that the carrier transport capacity was significantly enhanced, which improved the photocatalytic activity of g-C3N4. |
| Keywords: melamine g-C3N4 photocatalysis stability visible light |
| 投稿时间：2019-07-12 修订日期：2019-09-26 |
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| 叶仕雄,舒庆.硝酸活化三聚氰胺前驱体对g-C3N4结构和可见光催化性能的影响[J].无机化学学报,2020,36(1):1-10. |
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