title: Influence of functional groups on water splitting in carbon nanodot and graphitic carbon nitride composites: a theoretical mechanism study.
abstract: The coupling of carbon nanodots (C-Dots) with graphitic carbon nitride (g-C3N4) has been demonstrated to boost the overall photocatalytic solar water splitting efficiency. However, the understanding on the role of the C-Dots and how the structure of C-Dots influences the photocatalytic reaction is still limited. In this work, we investigate the excited states of some C-Dot/g-C3N4composites with the C-Dots containing different functional groups including -OH, -CHO and -COOH by first-principles many-body Green's function theory. It is found that the increase of efficiency can be ascribed to the high separation rate and the low recombination rate of the electron-hole pair benefiting from the emergence of the charge-transfer excited state between the C-Dots and g-C3N4. Functional groups on the C-Dots play a crucial role in determining the charge transfer direction, active sites for reduction reaction and oxidation reaction of water, and whether the reaction is a four-electron process or a two-electron/two-electron process. These results can provide guidance for the design and optimization of the C-Dots for heterojunction photocatalysts.
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, 250100, China. myc@sdu.edu.cn.
authors.forename: Jin
authors.initials: J
authors.lastname: Feng
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, 250100, China. myc@sdu.edu.cn.
authors.forename: Guokui
authors.initials: G
authors.lastname: Liu
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, 250100, China. myc@sdu.edu.cn.
authors.forename: Shiling
authors.initials: S
authors.lastname: Yuan
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, 250100, China. myc@sdu.edu.cn.
authors.forename: Yuchen
authors.identifier: http://orcid.org/0000-0002-9990-5023
authors.initials: Y
authors.lastname: Ma