Enhanced photocatalytic activity of mesoporous carbon/C3N4 composite photocatalysts

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

doi:10.1016/j.jcis.2017.10.081

Enhanced photocatalytic activity of mesoporous carbon/C₃N₄ composite photocatalysts

J Colloid Interface Sci. 2018 Feb 15:512:474-479. doi: 10.1016/j.jcis.2017.10.081. Epub 2017 Oct 24.

Authors

Affiliations

¹ Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
² Photocatalysis International Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-0022, Japan.
³ Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: dmli@iphy.ac.cn.
⁴ Photocatalysis International Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-0022, Japan. Electronic address: fujishima_akira@admin.tus.ac.jp.
⁵ Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: qbmeng@iphy.ac.cn.

PMID: 29096108
DOI: 10.1016/j.jcis.2017.10.081

Abstract

Hypothesis: The C₃N₄ as a cheap and clean photocatalyst shows suitable band gap to splitting water and spectral response. However the poor conductivity of C₃N₄ limits the photocatalytic hydrogen evolution rate. The combination of C₃N₄ and high conductivity materials will enhance the separation of photo-generated carriers and thus enhance the photocatalytic activity. As many carbon materials have been tried, the mesoporous carbon should be a good candidate to solve this problem.

Experiments: A photocatalytic system with C₃N₄ and mesoporous carbon has been designed to test the photocatalytic performance of both the photocatalytic hydrogen evolution and the photocatalytic degradation of methylene blue. The results of EPR, EIS and PL spectra were given to further understand the photo-generated carrier and its transfer.

Findings: The enhancement of the highest hydrogen evolution rate is 48% from 69 to 102 μmol/h by mesoporous carbon/C₃N₄ sample. The existence of small amount of mesoporous carbon can facilitate the photogenerated carrier separation, thus enhancing the photocatalytic performance. In the meantime, the introduction of mesoporous carbon into C₃N₄ is beneficial for improving electron delocalization and conduction electrons and increasing the optical absorption.

Keywords: Carbon nitride; Graphitic carbon nitride; Hydrogen evolution; Photocatalytic degradation; Water splitting.