Liu Runxue, Yang Wanliang, He Guiwei, Zheng Wei, Li Maokun, Tao Wenliang, Tian Mengkui
College of Chemistry and Chemical Engineering, Guizhou University, Guizhou 550025, China.
International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China.
ACS Omega. 2020 Jul 27;5(31):19615-19624. doi: 10.1021/acsomega.0c02161. eCollection 2020 Aug 11.
Ag-decorated g-CN (denoted as Ag/CN-) was prepared by a one-step calcination method, and the influences of calcination time on structure, morphology, surface composition, photocatalytic performance, and catalytic reduction activity of the prepared Ag/CN- samples were investigated. The tests showed that the Ag/CN-8 prepared through by calcination for 8 h exhibited the best photocatalytic degradation efficiency of methyl orange (98.7% within 2 h) and the best catalytic reduction property of 4-nitrophenol (100% within 70 s). Meanwhile, these Ag/CN- samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS), photoluminescence (PL), photocurrent response, and electrochemical impedance spectroscopy (EIS) Nyquist plots. It was found that the Ag/CN-8 prepared through calcination for 8 h had a higher specific surface area, higher dispersibility of silver nanoparticles (Ag NPs), the widest range of visible light response, and the lowest photogenerated electron-hole recombination rate. The results of the trapping experiments indicated that a superoxide radical plays a major role. Moreover, a possible mechanism of photocatalytic degradation in methyl orange and catalytic reduction 4-nitrophenol was proposed.
通过一步煅烧法制备了Ag修饰的g-CN（记为Ag/CN-），并研究了煅烧时间对所制备的Ag/CN-样品的结构、形貌、表面组成、光催化性能和催化还原活性的影响。测试表明，经8小时煅烧制备的Ag/CN-8表现出最佳的甲基橙光催化降解效率（2小时内为98.7%）和最佳的4-硝基苯酚催化还原性能（70秒内为100%）。同时，采用X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、布鲁诺尔-埃米特-泰勒（BET）、X射线光电子能谱（XPS）、紫外-可见漫反射光谱（DRS）、光致发光（PL）、光电流响应和电化学阻抗谱（EIS）奈奎斯特图对这些Ag/CN-样品进行了表征。发现经8小时煅烧制备的Ag/CN-8具有更高的比表面积、银纳米颗粒（Ag NPs）更高的分散性、最宽的可见光响应范围和最低的光生电子-空穴复合率。捕获实验结果表明，超氧自由基起主要作用。此外，还提出了甲基橙光催化降解和4-硝基苯酚催化还原的可能机理。
