化学学报 上一篇    

研究论文

石墨相氮化碳的共轭交联修饰及其对可见光催化产氢性能的影响

解众舒a,b, 薛中鑫b, 许子文b, 李倩a,b, 王洪宇*,a, 李维实*,b   

  1. a上海大学 理学院化学系 上海 200444;
    b中国科学院上海有机化学研究所有机功能分子合成与组装化学重点实验室 上海市 200032
  • 投稿日期:2022-04-21
  • 通讯作者: *wanghy@shu.edu.cn, liws@mail.sioc.ac.cn.
  • 基金资助:
    国家自然科学基金 (51761145043, 21975153), 中国科学院先导项目(XDB20020000),上海有机所项目(sioczz202123)和郑州工程技术学院项目.

Conjugated Cross-linking Modification of Graphitic Carbon Nitrides and Its Effect on Visible Light-Driven Photocatalytic Hydrogen Production

Xie Zhongshua,b, Xue Zhong-Xinb, Xu Zi-Wenb, Li Qiana,b, Wang Hongyu*,a, Li Wei-Shi*,b   

  1. aDepartment of Chemistry, Shanghai University, Shanghai 200444, China;
    bShanghai Institute of Organic Chemistry, Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
  • Received:2022-04-21
  • Supported by:
    National Natural Science Foundation of China (51761145043, 21975153), the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDB20020000), Shanghai Institute of Organic Chemistry (No. sioczz202123), and Zhengzhou Institute of Technology.

石墨相氮化碳 (GCN) 具有廉价易制和高度稳定性,在光催化分解水制氢领域备受关注,但其较窄的光谱响应范围和较低的光生电荷分离和转移效率制约了其光催化性能。本文采用4,4'-(苯并[c][1,2,5]噻二唑-4,7-二基)二苯甲醛 (BTD) 与热聚法合成的GCN在260℃进行酸催化席夫碱反应,使GCN片层发生共轭交联反应和表面修饰,制备了四个BTD改性的氮化碳材料GCN-BTDx (x为20、40、80和160,代表每100 mg GCN原料对应BTD的毫克用量)。其中,GCN-BTD160表现出最高的光催化还原水制氢性能,制氢速率为863 μmol g-1 h-1,是未修饰GCN的2倍,且展示出优秀的循环利用性能。研究发现,BTD修饰拓宽了材料的光吸收范围,调节了材料的能带结构,提高了电荷分离效率并降低了界面的电荷转移阻力,从而提高了材料的可见光催化制氢性能。

关键词: 石墨相氮化碳, 光催化, 分解水制氢, 可见光, 共轭修饰, 苯并噻二唑

Owing to their features of easy preparation, low cost and good stability, graphitic carbon nitrides (GCNs) have attracted increasing attention in the field of photocatalytic water-splitting hydrogen production for green and renewable energy as an alternative to fossil. However, their narrow light absorption spectra and low efficiencies in photogenerated charge separation and transfer processes restrict their photocatalytic performance. In this work, 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde (BTD) was used to conjugated crosslink and surface modify GCN via acid-catalyzed Shiff-base condensation reaction at 260 ℃, affording four BTD-modified graphitic carbon nitride materials denoted as GCN-BTDx (x represents the amount of BTD in mg used in the reaction with 100 mg GCN and equals to 20, 40, 80, and 160). Elemental analysis, Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, Mott-Schottky analysis, electrochemical impedance spectroscopy and photocurrent responsive measurements were used to characterize and investigate the synthesized materials. Using these materials as photocatalysts, triethanolamine as electron sacrificial agent, Pt nanoparticle as cocatalyst, visible light-driven photocatalytic hydrogen production from water have been studied. It was found the BTD modification can extend light absorption spectrum, tune energy band structure, and reduce interfacial charge transfer resistance, and thus finally improve the material photocatalytic hydrogen production performance. Among the family, GCN-BTD160 behaved the best with the highest hydrogen evolution rate (863 μmol g-1 h-1) and excellent stability and recyclability. Its hydrogen evolution rate is more than 2 folds as that of unmodified GCN. Moreover, GCN-BTD160 exhibited good visible light responsibility, with apparent quantum yields of 2.4% at 420 nm, 1.8% at 450 nm, and 1.6 % at 500 nm. Therefore, this work paves a new method in graphitic carbon nitride modification for photocatalytic performance improvement.

Key words: graphitic carbon nitrides, photocatalysis, water splitting hydrogen production, visible light, conjugated modification, benzothiadiazole