催化学报 ›› 2017, Vol. 38 ›› Issue (2): 278-286.DOI: 10.1016/S1872-2067(16)62561-5

• 论文 • 上一篇    下一篇

通过rGO与g-C3N4的π-π堆积作用提高氮化碳光化学氧化能力

郝强, 郝思濛, 牛秀秀, 李巽, 陈代梅, 丁浩   

  1. 中国地质大学(北京), 材料科学与工程学院, 北京 100083
  • 收稿日期:2016-08-20 修回日期:2016-09-26 出版日期:2017-02-18 发布日期:2017-03-14
  • 通讯作者: Daimei Chen,Tel:+86-15801558907;Fax:+86-10 82322974;E-mail:chendaimei@cugb.edu.cn;Hao Ding,E-mail:dinghao@cugb.edu.cn
  • 基金资助:

    国家自然科学基金(21577132);国家高技术研究发展计划(863计划,2012AA062701);中央高校基本科研业务费(2652015225);2015中国地质大学(北京)大学生创新创业训练计划(201511415069)

Enhanced photochemical oxidation ability of carbon nitride by π-π stacking interactions with graphene

Qiang Ha0, Simeng Ha0, Xiuxiu Niu, Xun Li, Daimei Chen, Hao Ding   

  1. Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China
  • Received:2016-08-20 Revised:2016-09-26 Online:2017-02-18 Published:2017-03-14
  • Contact: 10.1016/S1872-2067(16)62561-5
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21577132), the Fundamental Research Funds for the Central Universities (2652015225), National High Technology Research and Development Program of China (2012AA062701), Students Innovation and Entrepreneurship Training Program 2015 of China University of Geosciences (201511415069), Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes.

摘要:

石墨相氮化碳(g-C3N4)具有较高的催化活性、良好的生物相容性、廉价易得、低毒性等特点,因而受到了广泛的关注.g-C3N4的禁带宽度为2.7 eV,可被可见光激发,相对于二氧化钛和氧化锌,它对可见光具有更高的太阳光利用率.尽管理论上g-C3N4是类似于石墨烯结构的二维材料,但通常情况下g-C3N4却是层层堆积起来的三维体相结构.从而导致了其比表面积降低,催化反应过程中与反应物接触面积小.同时又使光照下生成的载流子不能迅速传递到材料表面参与反应,大大降低了g-C3N4光生载流子的分离和传递效率.另外,作为一种可见光催化剂,g-C3N4的禁带宽度比一般的无机半导体光催化剂窄,仅能够吸收部分可见光.本文利用原位煅烧法制备了g-C3N4/rGO复合光催化剂,以罗丹明B和2,4-二氯酚为目标探针分子,考察了其可见光催化活性.这对于设计开发其他具有共轭大π键的光催化体系,具有一定的借鉴意义.
X射线衍射(XRD),傅里叶变换红外光谱(FTIR),X射线光电子能谱(XPS)和激光共聚焦拉曼光谱(Raman)结果表明,氧化石墨烯成功地被还原为石墨烯,并成功地引入到了g-C3N4中去.在三聚氰胺聚合的过程中,石墨烯被夹杂在氮化碳的片层中间,有利于形成π-π共轭作用.
复合光催化剂C3N4/rGO的带边发生明显的红移,在可见光区域内的吸收强度也有所增加,因而有利于其可见光催化活性的提高.通过外推法算得g-C3N4和C3N4/rGO-1复合光催化剂的带隙宽度分别为2.70和2.42 eV.为了更好地考察复合光催化剂C3N4/rGO的能带结构的变化,通过光电化学的手段对其进行进一步的研究.莫特-肖特基结果表明该半导体是n型.计算得出g-C3N4和C3N4/rGO复合光催化剂的平带电势分别为-1.12和-0.85 V对甘汞标准电极,C3N4/rGO复合光催化剂的平带电位发生明显的正移.由此分别确定g-C3N4和C3N4/rGO复合光催化剂的价带底则位于1.58和1.74 V对甘汞标准电极.相比g-C3N4,g-C3N4/rGO复合光催化剂的价带位置的降低意味着其具有更强光氧化的能力,且比表面积的增大也有利于光催化反应.结果发现,石墨烯与g-C3N4的比例为1%时,复合样品的光催化性能最佳,对罗丹明B和2,4-二氯酚的降解性能均有提高.

关键词: 石墨相氮化碳, 还原氧化石墨烯, π-π堆积, 光催化, 相互作用

Abstract:

A one-pot method for the preparation of g-C3N4/reduced graphene oxide (rGO) composite photocatalysts with controllable band structures is presented. The photocatalysts are characterized by Fouirer transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, transmission electron microscope, and Mott-Schottky analysis. The valance band (VB) of g-C3N4 exhibits a noticeable positive shift upon hybridizing with rGO, and thus results in a strong photo-oxidation ability. The g-C3N4/rGO composites show a higher photodegradation activity for 2,4-dichlorophenol (2,4-DCP) and rhodamine B (RhB) under visible light irradiation (λ≥420 nm). The g-C3N4/rGO-1 sample exhibits the highest photocatalytic activity, which is 1.49 and 1.52 times higher than that of bulk g-C3N4 for 2,4-DCP and 1.52 times degradation, respectively. The enhanced photocatalytic activity for g-C3N4 originates from the improved visible light usage, enhanced electronic conductivity and photo-oxidation ability by the formed strong π-π stacking interactions with rGO.

Key words: Graphitic carbon nitride, Graphene oxide, π-&pi, stacking, Photocatalyst, Interaction