3-[(2-羟基-5-氯苯亚甲基)-氨基]-7-羟基香豆素钴配合物用于光催化还原CO_(2)  

The study of 3-[(2-hydroxy-5-chloro-benzylidene)-amino]-7-hydroxycoumarin cobalt complex for photocatalytic reduction of CO_(2)

作　　者：文国强 罗祥瑞 徐旭东 吴芳辉[1] 王婷婷 查习文 WEN Guoqiang;LUO Xiangrui;XU Xudong;WU Fanghui;WANG Tingting;ZHA Xiwen(School of Chemistry and Chemical Engineering,Anhui University of Technology,Ma'anshan,243002,China)

机构地区：[1]安徽工业大学化学与化工学院,马鞍山243002

出　　处：《环境化学》2023年第1期310-318,共9页Environmental Chemistry

基　　金：国家自然科学基金(21771003);生物膜法水质净化及利用技术教育部工程研究中心开放基金(BWPU2022KF04);安徽工业大学国家级大学生创新训练计划项目(202110360036)资助.

摘　　要：采用2,4-二羟基苯甲醛为起始原料合成了一种香豆素类席夫碱有机配体3-[(2-羟基-5-氯苯亚甲基)-氨基]-7-羟基香豆素CHB,接着将该配体与二价钴金属盐配位制备了新型的离子型金属-有机分子配合物CHB-Co,采用多种手段分别表征了配体和配合物的结构特征,然后研究了席夫碱类配合物CHBCo对CO_(2)还原的可见光催化活性.结果表明,优化各项实验条件后,配合物CHB-Co在H_(2)O/CH3CN溶液(V∶V=1∶4)中光催化CO_(2)还原的主要产物CO的产量为14.68μmol,转换数(TON)值达1468,转换率(TOF)值为146.8 h−1,选择性高达90%.通过不同光照时间下催化剂与光敏剂的紫外可见吸收光谱实验结果验证光催化过程中催化剂CHB-Co稳定存在,光敏剂的光降解是造成光催化体系停滞的主要原因.电化学实验结果显示CO_(2)氛围下配合物CHB-Co发生还原反应的起始电位位于−0.89 V(vs NHE),表明CHB-Co足以驱动电子从光敏剂的金属中心转移到催化剂,催化剂与光敏剂之间发生了有效的电子传递,从而催化CO_(2)发生还原反应.通过荧光光谱和荧光猝灭实验可知,牺牲剂不会对激发态光敏剂产生猝灭效应,而催化剂可以,并且随着催化剂浓度的增大,其对激发态光敏剂的猝灭效应也逐渐增强,表明催化剂CHB-Co与光敏剂之间能够较好地进行电子传输,从而展现出该材料在减轻环境污染和CO_(2)资源化利用方面的潜力.While 2,4-dihydroxy benzaldehyde was chosen as starting material,a coumarin Schiffbase ligand 3-[(2-hydroxy-5-chloro-benzylidene)-amino]-7-hydroxy-coumarin CHB was prepared.Subsequently,a novel cobalt Schiff base ionic metal-organic molecular complexes CHB-Co was synthesized and then characterized by various methods.The photocatalytic activities of this cobalt Schiff base complexes for visible-light-driven CO_(2) reduction were studied in detail.The experimental results show that CHB-Co possess excellent photocatalytic efficiency for CO_(2) reduction in H_(2)O/CH3CN solution(V∶V=1∶4)under the optimum conditions.The yield of the main product CO was 14.68µmol with the turnover number(TON)value of 1468 and the turnover frequency(TOF)value of 146.8 h−1.The selectivity was up to 90%.The results of UV-Vis absorption spectra of the catalyst and the photosensitizer under different illumination time verified that the catalysts CHB-Co was stable in the photocatalytic process,and the photodegradation of the photosensitizer was the main reason for the stagnation of the photocatalytic system.In contrast,electrochemical result showed that the initial potential of CHE-Co was−0.89 V(vs NHE),indicating that it is sufficient to drive electron transfer from the metal center of the photosensitizer toward the catalyst,and effective electron transfer occurred between the catalyst and the photosensitizer in the process of photocatalytic conversion of CO_(2).The fluorescence spectra and fluorescence quenching experiments showed that the sacrificial agent didn’t have quenching effect on the excited photosensitizer,while the catalyst did.With the increase of catalyst concentration,the quenching effect on the excited photosensitizer was gradually enhanced,suggesting that electron transport can be carried out between the catalyst and the photosensitizer.Therefore,above results show the perspective highlights of this material in reducing environmental pollution and the utilization of CO_(2) resources.

关 键 词：钴席夫碱配合物 合成 光催化 CO_(2) 还原 机理. 

分 类 号：O641.4[理学—物理化学] O643.36[理学—化学] O644.1