催化学报

催化学报

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g-C3N4/Bi8(CrO4)O11 S型异质结的自组装制备及其光催化降解诺氟沙星和双酚A

顾晓蒙a,b, 陈太杰a,d, 雷健a,b, 杨洋a,c,*, 郑秀珍a,b, 张素娟b, 朱秋实a, 付先亮b, 孟苏刚a,b,c,#, 陈士夫a,b,c   

  1. a淮北师范大学绿色和精准合成化学及应用教育部重点实验室, 安徽淮北235000;
    b淮北师范大学化学与材料科学学院, 清洁能源及绿色循环重点实验室, 安徽淮北235000;
    c淮北师范大学污染物敏感材料与环境修复安徽省重点实验室, 安徽淮北235000;
    d安庆师范大学化学化工学院, 功能配合物安徽省重点实验室, 安徽安庆246011
  • 收稿日期:2021-12-06 接受日期:2022-02-15
  • 通讯作者: *电话/传真: (0561)3802235; 电子信箱: yangy@chnu.edu.cn; #电子信箱: mengsugang@126.com; $电子信箱: chshifu@chnu.edu.cn
  • 基金资助:
    国家自然科学基金(52002142, 51972134); 安徽省高校优秀青年人才项目(gxyq2019029, gxbjZD2020066); 淮北师范大学研究生创新基金(yx2021019); 安徽省自然科学基金(2108085MB43, KJ2015TD003); 绿色和精准合成化学及应用教育部重点实验室项目(2020KF01); 中国科学院大连化学物理研究所催化基础国家重点实验室(N-20-09, N-20-10); 安徽省高效科研平台创新团队(KJ2015TD001); 上海同济高廷耀环保科技发展基金会.

Self-assembly synthesis of S-scheme g-C3N4/Bi8(CrO4)O11 for photocatalytic degradation of norfloxacin and bisphenol A

Gu Xiaomenga,b, Chen Taijiea,d, Lei Jiana,b, Yang Yanga,c,*, Zheng Xiuzhena,b, Zhang Sujuanb, Zhu Qiushia, Fu Xianliangb, Meng Suganga,b,c,#, Chen Shifua,b,c   

  1. aKey Laboratory of Green and Precise Synthetic Chemistry and applications, Ministry of Education, Huaibei Normal University, Huaibei 235000, Anhui, China;
    bKey Laboratory of Clean Energy and Green Circulation, College of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui, China;
    cAnhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental Remediation, Huaibei Normal University, Huaibei 235000, Anhui, China;
    dAnhui Key Laboratory of Functional Coordination Compounds, School of Chemistry and Chemical Engineering, Anqing Normal University, Anqing 246011, Anhui, China
  • Received:2021-12-06 Accepted:2022-02-15
  • Contact: * Tel/Fax: +86-561-3802235; E-mail: yangy@chnu.edu.cn; # E-mail: mengsugang@126.com; $ E-mail: chshifu@chnu.edu.cn
  • Supported by:
    National Natural Science Foundation of China (52002142, 51972134); the Project of Anhui Province for Excellent Young Talents in Universities (gxyq2019029, gxbjZD2020066); the funds for creative postgraduates of Huaibei Normal University (yx2021019); Natural Science Foundation of Anhui Province (2108085MB43, KJ2015TD003); the Project of Key Laboratory of Green and Precise Synthetic Chemistry and Applications (2020KF01); the fund of the State Key Laboratory of Catalysis in DICP (N-20-09 and N-20-10); Innovation Team of Scientific Research Platform of Anhui Province, China (KJ2015TD001); Shanghai Tongji Gao Tingyi Environmental Science & Technology Development Foundation, China (STGEF).

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摘要： 近年来,抗生素的过度使用导致了水体严重污染,威胁着生态环境安全和人体健康.太阳光驱动的半导体光催化技术被认为是一种有效去除污染物的手段.由于单一半导体光催化剂的多种缺陷,构建具有可见光响应和强氧化/还原能力的异质结光催化剂是去除有机污染物的有效途径.Bi8(CrO4)O11 (BCO)作为一种新发现的可见光响应半导体,由于较正的价带位,使得其在光催化污染物降解和水氧化方面显示了潜在的应用价值.然而,快速的载流子复合抑制了其活性.石墨相氮化碳(g-C3N4,CN)作为不含金属的半导体备受关注,其不仅具有可见光响应,环境友好和电子结构可调等优点,而且二维结构和较负的导带位使得CN更容易与其它半导体形成异质结光催化剂.因此,氧化型的BCO和还原型的CN结合构成异质结,有望形成S型载流子转移,从而提高光生电子-空穴对的分离效率,进而提高光催化降解污染物的活性.
本文通过自组装方法制备了一系列新型CN基异质结CN/BCO.CN/BCO异质结光催化降解诺氟沙星(NOR)和双酚A (BPA)的最优比为10%.相对于单体BCO和CN,10% CN/BCO对NOR的降解率分别提高了1.38倍和2.33倍; 10% CN/BCO对BPA的降解活性亦得到明显增强,其对BPA的降解率分别是纯 BCO和CN的1.35倍和9.11倍.光电流、电化学阻抗谱、稳态荧光和时间分辨瞬态荧光光谱证实了CN/BCO异质结可以显著提升BCO和CN的光生电子-空穴对的分离和迁移效率.原位X射线光电子能谱、电子顺磁共振和自由基捕获实验结果表明,CN/BCO异质结的光催化机制是S型转移.
紫外光电子能谱、价带XPS光谱以及载流子浓度等数据进一步揭示了CN/BCO异质结中光生载流子符合S型转移机理的原因.CN作为还原型光催化剂具有较高的费米能级,而BCO作为氧化型光催化剂具有较低的费米能级.此外,CN的载流子浓度大于BCO的载流子浓度.当CN和BCO接触,多子(电子)很容易从CN迁移到BCO,直到它们的费米能级相等.因此,在CN和BCO之间形成了交错的能带结构和由CN指向BCO的内电场,而且在空间电荷区CN的能带向上弯曲,而BCO的能带向下弯曲.当可见光激发CN和BCO产生光生载流子时,在内电场驱动下,BCO导带的电子向CN迁移,CN价带的空穴向BCO迁移; 而能带的弯曲和库仑斥力的作用,使得BCO价带的空穴和CN导带的电子各自留在原地.氧化还原能力弱的电子-空穴复合,而保留了空间分离的氧化还原能力强的电子和空穴,形成S型机制,从而显著提高了光催化活性.

关键词: Bi8(CrO4)O11, g-C3N4, 梯形机制, 光催化降解, 抗生素

Abstract: abstract: To realize the high-efficiency photodegradation of antibiotics, a novel S-scheme heterojunction photocatalyst g-C3N4/Bi8(CrO4)O11 was proposed and successfully prepared in this work. The 10% g-C3N4/Bi8(CrO4)O11 heterojunction exhibits the highest degradation rate of norfloxacin (NOR) and bisphenol A (BPA). The degradation rate of NOR on 10% g-C3N4/Bi8(CrO4)O11 is about 1.38 and 2.33 times higher than that of pure Bi8(CrO4)O11 and g-C3N4, respectively. Further, the degradation rate of BPA over 10% g-C3N4/Bi8(CrO4)O11 heterojunction is bout 1.35 and 9.11 times higher than that of pure Bi8(CrO4)O11 and g-C3N4, respectively. The formation of S-scheme heterojunction facilitates the separation of photogenerated electron-hole pairs and reduces the recombination of charge carriers, which was confirmed by photocurrent, electrochemical impedance spectroscopy, steady-state and time-resolved transient photoluminescence spectrum, etc. The in-situ X-ray photoelectron spectroscopy, radical trapping experiments and electron paramagnetic resonance results demonstrate that the charge transfer is in accord with S-scheme mechanism.

Key words: Bi8(CrO4)O11, g-C3N4, S-scheme, Photocatalytic degradation, Antibiotics