Fabricating intramolecular donor-acceptor system via covalent bonding of carbazole to carbon nitride for excellent photocatalytic performance towards CO2 conversion

Xianghai Song; Xinyu Zhang; Mei Wang; Xin Li; Zhi Zhu; Pengwei Huo; Yongsheng Yan

doi:10.1016/j.jcis.2021.02.105

Fabricating intramolecular donor-acceptor system via covalent bonding of carbazole to carbon nitride for excellent photocatalytic performance towards CO₂ conversion

J Colloid Interface Sci. 2021 Jul 15:594:550-560. doi: 10.1016/j.jcis.2021.02.105. Epub 2021 Mar 9.

Authors

Xianghai Song¹, Xinyu Zhang², Mei Wang³, Xin Li¹, Zhi Zhu¹, Pengwei Huo⁴, Yongsheng Yan⁵

Affiliations

¹ Institute of the Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
² College of Science, Beihua University, Jilin 132013, PR China.
³ School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, PR China.
⁴ Institute of the Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China. Electronic address: huopw@mail.ujs.edu.cn.
⁵ Institute of the Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China. Electronic address: yys@mail.ujs.edu.cn.

PMID: 33774411
DOI: 10.1016/j.jcis.2021.02.105

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.

Keywords: CO(2) reduction; Carbon nitride; Covalent bonded; Donor-acceptor; Photocatalysis.