KNO3-Assisted incorporation of K dopants and N defects into g-C3N4 with enhanced visible light driven photocatalytic H2O2 production

Doping with heteroatoms and introducing defects are efficient protocols to enhance the photocatalytic performance of graphitic carbon nitride (g-C3N4) for H2O2 production. Herein, a facile one-pot KNO3-assisted thermal polymerization of thiourea and urea was reported for the modification of g-C3N4 w...

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Bibliographic Details
Published in:New journal of chemistry 2021-12, Vol.45 (48), p.22591-22601
Main Authors: Yang, Haihua, Qian, Xiaorong, Zhang, Na, Zhang, Li, Zhou, Minjie
Format: Article
Language:English
Subjects:
Carbon nitride
Conduction bands
Cyano groups
Defects
Dopants
Electromagnetic absorption
Electron transfer
Electronic structure
Electrons
Energy gap
Hydrogen peroxide
Lamellar structure
Photocatalysis
Reduction
Synergistic effect
Thioureas
Ureas
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Summary:Doping with heteroatoms and introducing defects are efficient protocols to enhance the photocatalytic performance of graphitic carbon nitride (g-C3N4) for H2O2 production. Herein, a facile one-pot KNO3-assisted thermal polymerization of thiourea and urea was reported for the modification of g-C3N4 with K dopants and N defects (denoted as M-CN-K-1). As a visible light photocatalyst with isopropanol as an electron donor, the obtained M-CN-K-1 sample exhibited an excellent H2O2 production activity of 2.92 mmol g−1 g-C3N4 h−1, which was 15.6, 5.8 and 2.2 times that of pristine g-C3N4 samples derived from urea, thiourea, and a mixture of thiourea and urea, respectively. The outstanding performance of the KNO3-modified g-C3N4 is attributed to the controllable introduction of cyano groups on the opened s-triazine heterocycle and K insertion into the g-C3N4 layers, which are conducive to regulating the morphology, electronic structure, and electron withdrawing and transfer capability. The KNO3-modified g-C3N4 possesses a lamellar structure with a high surface area, smaller energy gap for broadened visible light absorption, more negative conduction band position with stronger reduction ability, suppressed recombination of electron–hole pairs, and enhanced electron transfer, which exert a synergistic effect on the photocatalytic H2O2 production. The H2O2 formation in M-CN-K-1 undergoes the pathway of two-step one-electron indirect O2 reduction (O2 → ·O2−→ H2O2). This study provides a facile and promising strategy for the modification of g-C3N4 to boost the photocatalytic H2O2 production activity.
ISSN:1144-0546
1369-9261
DOI:10.1039/d1nj04682a