徐苏倩,张晓,程婷,王津南.具有双反应活性中心Cu-Al2O3-g-C3N4类芬顿催化剂及·OH选择性转化机理研究[J].环境科学学报,2021,41(2):512-525
具有双反应活性中心Cu-Al2O3-g-C3N4类芬顿催化剂及·OH选择性转化机理研究
- The synthesis of Fenton like catalyst Cu-Al2O3-g-C3N4 with double catalytic active centers and the mechanism of selective conversion of H2O2 to hydroxyl radical
- 基金项目：江苏省高校自然科学研究项目（No.17KJD610002）
- 徐苏倩
- 江苏开放大学, 环境生态学院, 南京 210019
- 张晓
- 江苏开放大学, 环境生态学院, 南京 210019
- 程婷
- 江苏开放大学, 环境生态学院, 南京 210019
- 王津南
- 南京大学环境学院, 污染物与资源化研究国家重点实验室, 南京 210023
- 摘要：采用水热合成法制备Cu-Al2O3-g-C3N4类芬顿催化剂，以扫描电镜（SEM）、X射线衍射（XRD）、X射线光电子能谱（XPS）、电子自旋共振（EPR）、拉曼光谱（Raman）对所制备的催化剂及反应过程进行表征.以染料亚甲基蓝（MB）和罗丹明B（Rh-B）及小分子有机物2，4-二氯苯氧乙酸（2，4-D）、双酚A（BPA）和苯妥英（PHT）为目标污染物，研究催化剂在初始pH=7条件下的类芬顿催化活性.同时，探讨Cu掺杂量和有机物配体g-C3N4掺杂量对体系催化性能的影响，并验证晶格氧诱发与有机配体络合两种方式对催化剂活性和稳定性提高产生的影响.DMPO-EPR自由基测定实验及Raman光谱监测催化反应过程验证表明：Cu的晶格氧掺杂诱发了靠近铜晶格O2·-的富电子Cu中心，以及靠近铝晶格O2·-的缺电子Al中心；引入的g-C3N4以阳离子π作用形式通过σ-型Cu—O—C键桥将π体系上的电子转移至Cu，形成一个新的缺电子π中心.在H2O2存在的情况下，富电子Cu中心将电子传递给H2O2，使其被还原为·OH；同时，体系中H2O的电子被缺电子中心剥夺，进而氧化为·OH.羟基自由基转化率TOFs值的进一步计算结果表明，Cu-Al2O3-g-C3N4体系中TOF值为0.516 s-1，是传统均相芬顿体系TOF值（1.53×10-2 s-1）的33倍以上.
- Abstract：A Fenton-like catalyst, Cu-Al2O3-g-C3N4, was synthesized by a high pressure hydrothermal method, and the scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron (XPS), electron paramagnetic resonance (EPR) and Roman were applied to characterizes both Cu-Al2O3-g-C3N4 and its reaction process. To further analyze the catalytic capability of Cu-Al2O3-g-C3N4 for Fenton-like reation(pH=7),methylene blue (MB),Rhodamine B (RhB), Bisphenol A (BPA), Phenytoin (PHT) and 2,4-dichlorophenoxyaceticacid (2,4-D) were selected as model pollutants. Effect of the doping amount of Cu and g-C3N4 during the preparation of Cu-Al2O3-g-C3N4 on Rh B degradation was discussed. DMPO-trapped EPR signals and Raman spectroscopy reveal that lattice substitution of Cu for Al induces the formation of electron-rich Cu center and the electron-deficient Al center. Surface Cu coordinates with the hydroxyl on the tri-s-triazine ring of g-C3N4 through Cu—O—C linker so that the orbital interactions involving electron transport from π→Cu also induces the formation of another electron-rich Cu center and a new electron-deficient π-electron conjugated system. This kind of surface structure facilitates the reduction of H2O2 to ·OH at the electron-rich Cu center and the oxidation of H2O to ·OH at the electron-deficient Al center or electron-deficient π-electron conjugated system. Turnover frequency (TOF) for the Cu-Al2O3-g-C3N4 dispersions was 0.516 s-1 under neutral conditions, which was still 33 times higher than those of the class homogeneous Fenton reaction under strongly acidic conditions (1.53×10-2 s-1).
