Defects Promote Ultrafast Charge Separation in Graphitic Carbon Nitride for Enhanced Visible-Light-Driven CO2 Reduction Activity
发表时间：2019-11-07
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- 论文类型：
- 期刊论文
- 第一作者：
- Shi, Hainan
- 通讯作者：
- Hou, JG; Li, KY; Guo, XW (reprint author), Dalian Univ Technol, Sch Chem Engn, PSU DUT Joint Ctr Energy Res, State Key Lab Fine Chem, Dalian 116024, Peoples R China.
- 合写作者：
- Guo, Xinwen,Long, Saran,Hou, Jungang,Ye, Lu,Sun, Yanwei,Ni, Wenjun,Song, Chunshan,Li, Keyan,Gurzadyan, Gagik G.
- 发表时间：
- 2019-04-01
- 发表刊物：
- CHEMISTRY-A EUROPEAN JOURNAL
- 收录刊物：
- PubMed、EI、SCIE
- 文献类型：
- J
- 卷号：
- 25
- 期号：
- 19
- 页面范围：
- 5028-5035
- ISSN号：
- 0947-6539
- 关键字：
- carbon nitride; N defects; photochemistry; CO2 reduction
- 摘要：
- Fundamental photocatalytic limitations of solar CO2 reduction remain due to low efficiency, serious charge recombination, and short lifetime of catalysts. Herein, two-dimensional graphitic carbon nitride nanosheets with nitrogen vacancies (g-C3Nx) located at both three-coordinate N atoms and uncondensed terminal NHx species were prepared by one-step tartaric acid-assistant thermal polymerization of dicyandiamide. Transient absorption spectra revealed that the defects in g-C3N4 act as trapped states of charges to result in prolonged lifetimes of photoexcited charge carriers. Time-resolved photoluminescence spectroscopy revealed that the faster decay of charges is due to the decreased interlayer stacking distance in g-C3Nx in favor of hopping transition and mobility of charge carriers to the surface of the material. Owing to the synergic virtues of strong visible-light absorption, large surface area, and efficient charge separation, the g-C3Nx nanosheets with negligible loss after 15 h of photocatalysis exhibited a CO evolution rate of 56.9 mu mol g(-1) h(-1) under visible-light irradiation, which is roughly eight times higher than that of pristine g-C3N4. This work presents the role of defects in modulating light absorption and charge separation, which opens an avenue to robust solar-energy conversion performance.
- 是否译文：
- 否
