Sodium-doped carbon nitride nanotubes for efficient visible light-driven hydrogen production  

作　　者：Longshuai Zhang Ning Ding Muneaki Hashimoto Koudai Iwasaki Noriyasu Chikamori Kazuya Nakata Yuzhuan Xu Jiangjian Shi Huijue Wu Yanhong Luo Dongmei Li Akira Fujishima Qingbo Meng 

机构地区：[1]Key Laboratory for Renewable Energy, Chinese Academy of Sciences (CAS), Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190, China [2]Photocatalysis International Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-0022, Japan [3]School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Nano Research》2018年第4期2295-2309,共15页纳米研究（英文版）

基　　金：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.

摘　　要：Sodium-doped carbon nitride nanotubes （Nax-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 Lix-CNNTs and Kx-CNNTs, were tested; both materials were found to enhance the hydrogen evolution rate, but to a lower extent compared with the Nax-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 Nax-CNNTs is also proposed.Sodium-doped carbon nitride nanotubes （Nax-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 Lix-CNNTs and Kx-CNNTs, were tested; both materials were found to enhance the hydrogen evolution rate, but to a lower extent compared with the Nax-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 Nax-CNNTs is also proposed.

关 键 词：graphitic carbon nitrides NANOTUBES alkali metal doping photocatalytic hydrogen production hydrothermal/thermopolymerization processes two-step synthesis 

分 类 号：O614.112[理学—无机化学] TG142.33[理学—化学]