Ning Ding1, Longshuai Zhang1, Muneaki Hashimoto2, Kodai Iwasaki2, Noriyasu Chikamori2, Kazuya Nakata2, Yuzhuan Xu1, Jiangjian Shi1, Huijue Wu1, Yanhong Luo1, Dongmei Li3, Akira Fujishima4, Qingbo Meng5. 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.
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.
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.