The pivotal role of defects in fabrication of polymeric carbon nitride homojunctions with enhanced photocatalytic hydrogen evolution

Quanhua Deng; Haiping Li; Guiming Ba; Tingting Huo; Wanguo Hou

doi:10.1016/j.jcis.2020.10.144

The pivotal role of defects in fabrication of polymeric carbon nitride homojunctions with enhanced photocatalytic hydrogen evolution

J Colloid Interface Sci. 2021 Mar 15:586:748-757. doi: 10.1016/j.jcis.2020.10.144. Epub 2020 Nov 13.

Authors

Quanhua Deng¹, Haiping Li², Guiming Ba³, Tingting Huo³, Wanguo Hou⁴

Affiliations

¹ School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China.
² National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China. Electronic address: hpli@sdu.edu.cn.
³ National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China.
⁴ National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China. Electronic address: wghou@sdu.edu.cn.

PMID: 33220957
DOI: 10.1016/j.jcis.2020.10.144

Abstract

Fabrication of homojunctions is a cost-effective efficient way to enhance the photocatalytic performance of polymeric carbon nitride (CN), but the generation of defects upon synthesizing CN homojunctions and their roles in the homojunction fabrication were hardly reported. Herein, nitrogen-deficient CN homojunctions were simply synthesized by calcining dicyandiamide-loaded CN (prepared from urea and denoted as UCN) with dicyandiamide polymerizing into CN (denoted as DCN) and simultaneous formation of nitrogen vacancies in the surface of UCN. Fabrication of the nitrogen-deficient UCN (dUCN)/DCN homojunction depends on the nitrogen vacancy content in dUCN which can tune the energy band structure of dUCN from not matching to matching with that of DCN. The dUCN/DCN homojunction exhibits extended optical absorption and remarkably enhanced charge separation and photocatalytic H₂ evolution, compared with UCN and DCN. This work illustrates the pivotal role of defects in fabricating CN homojunctions and supplies a new facile way to synthesize nitrogen-deficient CN.

Keywords: Carbon nitride; Homojunction; Hydrogen evolution; Nitrogen vacancy; Photocatalysis.