1. Fabricating intramolecular donor-acceptor system via covalent bonding of carbazole to carbon nitride for excellent photocatalytic performance towards CO2 conversion
- Author
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Xianghai Song, Xinyu Zhang, Mei Wang, Pengwei Huo, Xin Li, Zhi Zhu, and Yongsheng Yan
- Subjects
Materials science ,business.industry ,Carbazole ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Biomaterials ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Semiconductor ,chemistry ,Chemical bond ,Covalent bond ,Intramolecular force ,Photocatalysis ,Charge carrier ,0210 nano-technology ,business ,Carbon nitride - Abstract
Photocatalytic conversion of CO2 into hydrocarbon fuels is an ideal technology of mitigating greenhouse effect caused by excessive emission of CO2. However, the high recombination rate of electron-hole pairs and limited charge carriers transport speed constrained the catalytic performance of many semiconductor catalysts. In this contribution, a series of carbon nitride (g-CN) samples with intramolecular donor-acceptor (D-A) system were successfully prepared by introducing organic donor into their structures. Characterization results confirmed that carbazole was successful connected to the structure of g-CN via chemical bond. The formation of intramolecular D-A system greatly enlarged the light response region of g-CN-xDbc. In addition, a new charge transfer transition mode was formed in g-CN-0.01Dbc due to the incorporation carbazole, which enable it to use light with energy lower than the intrinsic absorption of g-CN. Meanwhile, the D-A structure led to the spatial separation of electrons and holes in g-CN-xDbc and significantly decreased the recombination rate of electron-hole pairs. The g-CN-0.01Dbc presented the best catalytic performance and the CO evolution rate was 9.6 times higher than that of g-CN. Moreover, the reaction was performed in water without any additive, which made it green and sustainable. DFT simulation confirmed the D-A structure and charge carrier migration direction in the prepared samples.
- Published
- 2021