A graphitic carbon nitride metal-free visible light photocatalyst with controllable carbon self-doping towards efficient hydrogen evolution. Issue 20 (14th September 2021)

• Record Type: Journal Article
• Authors: Lei, Lin; Wang, Weijia; Xie, Zhengfeng; Wu, Xiaobo; Yadav, Arun Kumar; Müller-Buschbaum, Peter; Fan, Huiqing
• Is Part Of: Sustainable energy & fuels. Volume 5:Issue 20(2021)
• Page Start: 5227
• Page End: 5235
• Publication Date: 2021-09-14
• Subjects: Renewable energy sources -- Periodicals; Fuel cells -- Periodicals; Electric batteries -- Periodicals; Electrochemistry -- Periodicals; 660.297
• DOI: 10.1039/d1se01244d
• Languages: English
• ISSNs: 2398-4902

Abstract

Abstract : The substitution of sp 2 -hybridized nitrogen atoms by carbon atoms in graphitic carbon nitride is beneficial for electron delocalization and suppresses radiative recombination due to the formation of a C–C bond. Abstract : Controlling molecular defects via element doping is an effective strategy for tailoring electronic structures and charge separation in photocatalysts. However, the rational design of self-doped catalysts is generally confronted with the need for expensive reagents, high dopant ratios and environmentally unfriendly materials. Herein, carbon self-doped graphitic carbon nitride (DCN- x ) is obtained via one-pot thermal polymerization of urea and d -mannitol. The sp 2 -hybridized nitrogen atoms are partially substituted by carbon atoms from dopants. The corresponding defects provide the photocatalyst with extended light harvesting up to 600 nm, a tunable optical bandgap, and the formation of more delocalized electrons with a uniform distribution at the defect scope of a C–C bond. In addition, increased band-tail states are found in DCN-3, which greatly enhance charge separation. A high photocatalytic hydrogen evolution rate of 3180 μmol g −1 h −1 is achieved under visible light irradiation ( λ > 420 nm), which is about 5.3 fold higher than that of pristine g-C3 N4 . This work provides a green and economical method to synthesize g-C3 N4 with controllable carbon self-doping sites for efficient energy conversion related applications.