Sodium-doped carbon nitride nanotubes for efficient visible light-driven hydrogen production
- 736 Downloads
Sodium-doped carbon nitride nanotubes (Na x -CNNTs) were prepared by a green and simple two-step method and applied in photocatalytic water splitting for the first time. Transmission electron microscopy (TEM) element mapping and X-ray photoelectron spectroscopy (XPS) measurements confirm that sodium was successfully introduced in the carbon nitride nanotubes (CNNTs), and the intrinsic structure of graphitic carbon nitride (g-C3N4) was also maintained in the products. Moreover, the porous structure of the CNNTs leads to relatively large specific surface areas. Photocatalytic tests indicate that the porous tubular structure and Na+ doping can synergistically enhance the hydrogen evolution rate under visible light (λ > 420 nm) irradiation in the presence of sacrificial agents, leading to a hydrogen evolution rate as high as 143 μmol·h−1 (20 mg catalyst). Moreover, other alkali metal-doped CNNTs, such as Li x -CNNTs and K x -CNNTs, were tested; both materials were found to enhance the hydrogen evolution rate, but to a lower extent compared with the Na x -CNNTs. This highlights the general applicability of the present method to prepare alkali metal-doped CNNTs; a preliminary mechanism for the photocatalytic hydrogen evolution reaction in the Na x -CNNTs is also proposed.
Keywordsgraphitic carbon nitrides nanotubes alkali metal doping photocatalytic hydrogen production hydrothermal/thermopolymerization processes two-step synthesis
Unable to display preview. Download preview PDF.
The authors would like to thank the financial support from Sakura Science Program (Japan Science and Technology Agency), National Natural Science Foundation of China (Nos. 51627803, 51402348, 11474333, 91433205, 51421002, and 51372270) and the Knowledge Innovation Program of the Chinese Academy of Sciences.
- Wang, Q.; Hisatomi, T.; Jia, Q. X.; Tokudome, H.; Zhong, M.; Wang, C. Z.; Pan, Z. H.; Takata, T.; Nakabayashi, M.; Shibata, N. et al. Scalable water splitting on particulate photocatalyst sheets with a solar-to-hydrogen energy conversion efficiency exceeding 1%. Nat. Mater. 2016, 15, 611–615.CrossRefGoogle Scholar
- Zada, A.; Humayun, M.; Raziq, F.; Zhang, X. L.; Qu, Y.; Bai, L. L.; Qin, C. L.; Jing, L. Q.; Fu, H. G. Exceptional visible-light-driven cocatalyst-free photocatalytic activity of g-C3N4 by well designed nanocomposites with plasmonic Au and SnO2. Adv. Energy Mater. 2016, 6, 1601190.CrossRefGoogle Scholar
- Chen, X. F.; Jun, Y. S.; Takanabe, K.; Maeda, K.; Domen, K.; Fu, X. Z.; Antonietti, M.; Wang, X. C. Ordered meso-porous SBA-15 type graphitic carbon nitride: A semicon-ductor host structure for photocatalytic hydrogen evolution with visible light. Chem. Mater. 2009, 21, 4093–4095.CrossRefGoogle Scholar
- Zhu, Y. N.; Cao, C. Y.; Jiang, W. J.; Yang, S. L.; Hu, J. S.; Song, W. G.; Wan, L. J. Nitrogen, phosphorus and sulfur co-doped ultrathin carbon nanosheets as a metal-free catalyst for selective oxidation of aromatic alkanes and the oxygen reduction reaction. J. Mater. Chem. A 2016, 4, 18470–18477.CrossRefGoogle Scholar
- Hu, S. Z.; Chen, X.; Li, Q.; Li, F. Y.; Fan, Z. P.; Wang, H.; Wang, Y. J.; Zheng, B. H.; Wu, G. Fe3+ doping promoted N2 photofixation ability of honeycombed graphitic carbon nitride: The experimental and density functional theory sim-ulation analysis. Appl. Catal. B: Environ. 2017, 201, 58–69.CrossRefGoogle Scholar
- Sing, K. S. W.; Everett, D. H.; Haul, R. A. W.; Moscou, L.; Pierotti, R. A.; Rouquérol, J.; Siemieniewska, T. Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (Recommendations 1984). Pure Appl. Chem. 1985, 57, 603–619.CrossRefGoogle Scholar
- Zhang, J. K.; Yu, Z. B.; Gao, Z.; Ge, H. B.; Zhao, S. C.; Chen, C. Q.; Chen, S.; Tong, X. L.; Wang, M. H.; Zheng, Z. F. et al. Porous TiO2 nanotubes with spatially separated platinum and CoOx cocatalysts produced by atomic layer deposition for photocatalytic hydrogen production. Angew. Chem., Int. Ed. 2017, 56, 816–820.CrossRefGoogle Scholar