One-step preparation of halogenated aminobenzonitrile modified g-C3N4 via copolymerization and in situ halogen doping for highly enhanced visible light hydrogen evolution

• Published in: International journal of hydrogen energy 2020-02, Vol.45 (11), p.6341-6351
• Main Authors: Lin, Zhi, Wang, Shijia, Miao, Yiqian, Yuan, Jinping, Liu, Yingliang, Xu, Shengang, Cao, Shaokui
• Format: Article
• Language: English
• Subjects: Copolymerization; g-C3N4; Halogenated aminobenzonitrile; In situ doping; Photocatalytic hydrogen evolution
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2019.12.123

A series of halogenated aminobenzonitrile modified graphitic carbon nitride (g-C3N4) was prepared by a one-step calcination of dicyandiamide and 2-amino-5-halogen-benzonitriles (X-ABN, X = F, Cl, Br or I, 1.67 wt% of dicyandiamide) together, and named as X-ABN-CN. The resulting X-ABN-CN photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffuse reflection spectroscopy, and photoluminescence spectroscopy. The characterization results indicated that X-ABN-CN have been successfully prepared, and the π-conjugated system and electronic structure of X-ABN-CN could be improved via copolymerization, Ullmann reaction and in situ halogen doping. Under visible light irradiation (λ > 400 nm), the photocatalytic activity of X-ABN-CN were much higher than that of pure g-C3N4 and increase with the increase of halogen atomic number. The hydrogen evolution rate of I-ABN-CN (131.4 μmol h−1) was 7.4 times that of g-C3N4 (17.7 μmol h−1). Furthermore, the corresponding mesoporous X-ABN-CN (X-ABN-MCN, X = F, Cl, Br or I) were prepared by using SiO2 nanoparticles as template. As expected, I-ABN-MCN showed the highest photocatalytic activity in all mesoporous samples, which is about 8.8 times that of g-C3N4. The results manifest that the copolymerization, Ullmann reaction, in situ halogen doping and mesoporous structure could be integrated together to modify g-C3N4 by a simple one-step calcination process. [Display omitted] •Halogenated aminobenzonitriles modified g-C3N4 (X-ABN-CN) were prepared by one-step calcination.•Photocatalytic activity of X-ABN-CN are much higher than that of g-C3N4.•The aromatic rings could be incorporated into g-C3N4 network via copolymerization.•The halogen ions generated by Ullmann reaction could improve the electronic structure.