研究报告
张塞,张丽丽,胡春.氮化碳增强Ag/AgI/γ-Al2O3的可见光催化性能及其机理[J].环境科学学报,2017,37(10):3755-3763
氮化碳增强Ag/AgI/γ-Al2O3的可见光催化性能及其机理
- Enhanced visible-light photocatalytic performance and mechanism of Ag/AgI/γ-Al2O3 coupling with carbon nitride
- 基金项目：国家自然科学基金（No.51538013）；国家重点研发计划项目（No.2016YFA0203200）
- 作者
- 单位
- 张塞
- 1. 中国科学院生态环境研究中心, 环境水质学国家重点实验室, 北京 100085;2. 中国科学院大学资源与环境学院, 北京 100049
- 张丽丽
- 中国科学院生态环境研究中心, 环境水质学国家重点实验室, 北京 100085
- 胡春
- 1. 中国科学院生态环境研究中心, 环境水质学国家重点实验室, 北京 100085;2. 中国科学院大学资源与环境学院, 北京 100049
- 摘要：通过热聚合的方法使氮化碳（CN）与Ag/AgI/γ-Al2O3发生耦合作用，制备出CN-Ag/AgI/γ-Al2O3可见光催化剂.采用X射线衍射（XRD）、X射线光电子能谱（XPS）、透射电子显微镜（TEM）和紫外可见漫反射光谱（UV-vis DRS）等方法对合成的样品进行了表征，并通过可见光下甲基橙（MO）的降解实验探究了CN对Ag/AgI/γ-Al2O3光催化活性及稳定性的影响.结果表明，CN的掺杂改变了Ag纳米颗粒的形状与粒径，且Ag、AgI与CN之间形成强相互作用.与Ag/AgI/γ-Al2O3相比较，在可见光波长分别为λ > 420、450和510 nm时，CN-Ag/AgI/γ-Al2O3对MO具有更高的催化降解效率，光反应30 min后，MO的去除率分别为97%、97%和93%.同时，CN的加入显著地增加了Ag/AgI/γ-Al2O3的稳定性，抑制了反应过程中Ag+的释放量，而且反应前后CN-Ag/AgI/γ-Al2O3样品的结构没有明显的变化.其活性和稳定性提高的主要原因是CN加速了电子由MO传递至Ag纳米颗粒的过程，同时Ag颗粒等离子体共振（plasmon）效应的增强也有利于MO的催化降解.不同自由基捕获剂的影响实验表明，O2·-和h+是反应体系的主要活性物种.
- Abstract：CN-Ag/AgI/γ-Al2O3 was successfully prepared by coupling carbon nitride (CN) with Ag/AgI/γ-Al2O3 via a thermal polymerization method, which was then characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). The effect of CN on the photocatalytic activity and stability was then investigated by degrading MO under visible light irradiation. The results indicated that the shapes and sizes of Ag nanoparticles were changed with the addition of CN, and the strong interfacial interactions were formed among Ag, AgI and CN. Compared with Ag/AgI/γ-Al2O3, CN-Ag/AgI/γ-Al2O3 catalyst exhibited better photocatalytic activity for MO degradation at λ > 420, 450 and 510 nm with the removal rate at about 97%, 97% and 93%, respectively. Meanwhile, the incorporation of CN improved the photostability of Ag/AgI/γ-Al2O3 and significantly suppressed the releasing of Ag+, and meanwhile the XRD pattern of CN-Ag/AgI/γ-Al2O3 was not changed after the photoreaction. The improvements of photocatalytic activity and stability were attributed to the existence of CN by accelerating interfacial electrons transfer from MO to Ag NPs. Besides, enhancement of Ag plasmon effect was beneficial to MO degradation.O2·- radicals and excited h+ were measured as main active species involved in the photoreaction system.
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