Which kind of nitrogen chemical states doped carbon dots loaded by g-C3N4 is the best for photocatalytic hydrogen production

Shuaiyang Zhang; Mengjie Gao; Yunpu Zhai; Jiaqi Wen; Jingkun Yu; Tiwei He; Zhenhui Kang; Siyu Lu

doi:10.1016/j.jcis.2022.04.165

Which kind of nitrogen chemical states doped carbon dots loaded by g-C₃N₄ is the best for photocatalytic hydrogen production

J Colloid Interface Sci. 2022 Sep 15:622:662-674. doi: 10.1016/j.jcis.2022.04.165. Epub 2022 Apr 30.

Authors

Shuaiyang Zhang¹, Mengjie Gao¹, Yunpu Zhai², Jiaqi Wen¹, Jingkun Yu¹, Tiwei He³, Zhenhui Kang⁴, Siyu Lu⁵

Affiliations

¹ Green Catalysis Center, College of Chemistry, Zhengzhou University, 100 Kexue Avenue, Zhengzhou 450001, Henan, PR China.
² Green Catalysis Center, College of Chemistry, Zhengzhou University, 100 Kexue Avenue, Zhengzhou 450001, Henan, PR China. Electronic address: yunpu.zhai@zzu.edu.cn.
³ Institute of Functional Nano & Soft Materials, Soochow University, 199 Renai Road, Suzhou 215123, Jiangsu, PR China.
⁴ Institute of Functional Nano & Soft Materials, Soochow University, 199 Renai Road, Suzhou 215123, Jiangsu, PR China. Electronic address: zhkang@suda.edu.cn.
⁵ Green Catalysis Center, College of Chemistry, Zhengzhou University, 100 Kexue Avenue, Zhengzhou 450001, Henan, PR China. Electronic address: sylu2013@zzu.edu.cn.

PMID: 35533481
DOI: 10.1016/j.jcis.2022.04.165

Abstract

Recently, g-C₃N₄ (CN) loaded N-doped carbon dots (NCDs) have been widely studied as promising metal-free photocatalysts due to their impressive performance in hydrogen production. However, deep understanding of the effect of nitrogen chemical states on photocatalytic activity is still lacked. In this work, NCDs doped with pyrrole nitrogen, graphite/pyrrole nitrogen, and pyrrole/pyridine nitrogen were prepared and hybridized with g-C₃N₄. The characterizations revealed that, incorporation of pyrrole N-doped CDs into g-C₃N₄ (CN/NCDs-en) effectively enhanced the visible light absorption, facilitated electron-hole separation, and promoted the participation of photoexcited electrons in H₂ evolution reaction. Moreover, theoretical calculation showed that, compared with graphite N and pyridine N, pyrrole N has the most appropriate H adsorption ability, which is conducive to the H₂ formation. Under visible light irradiation, the CN/NCDs-en exhibited the best hydrogen evolution of 3028 μmol h^-1 g^-1. These results shed a light on the design and optimization of N-doped metal-free photocatalysts for H₂ evolution reaction.

Keywords: Active sites; Hydrogen evolution; N-doped carbon dots; Photocatalyst; g-C(3)N(4).