Loading sulfur and nitrogen co-doped carbon dots onto g-C3N4 nanosheets for an efficient photocatalytic reduction of 4-nitrophenol

Abstract

A favorable interface for hybrid photocatalysts makes an important contribution in enhancing photocatalytic reactions. Herein we located sulfur and nitrogen co-doped carbon dots (SN-CDs) onto g-C₃N₄ nanosheets and achieved a novel SN-CD/g-C₃N₄ composite with a high visible-light photocatalytic reduction of 4-nitrophenol (4-NP). Compared to g-C₃N₄ nanosheets, the SN-CD/g-C₃N₄ composite possessed a wider light absorption. More importantly, the interaction of surface groups led to a favorable interfacial bonding between SN-CDs and g-C₃N₄ nanosheets, which facilitated the transfer of photoexcited electrons and holes, giving rise to an improved electron transport ability of the composite. In addition, the upward shift of the energy band of g-C₃N₄ nanosheets due to the location of SN-CDs led to a stronger reducibility of charge carriers. As a consequence, the photocatalytic performance of SN-CD/g-C₃N₄ has been remarkably improved in the photocatalytic reduction of 4-nitrophenol.