Metal-free broad-spectrum PTCDA/g-C3N4 Z-scheme photocatalysts for enhanced photocatalytic water oxidation

• Published in: Applied catalysis. B, Environmental Vol. 260; p. 118179
• Main Authors: Yuan, Yong-Jun, Shen, Zhi-Kai, Wang, Pei, Li, Zijian, Pei, Lang, Zhong, Jiasong, Ji, Zhenguo, Yu, Zhen-Tao, Zou, Zhigang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-01-2020; Elsevier BV
• Subjects: Broad-Spectrum responsive; Carbon nitride; Cobalt oxides; Conduction; Conduction bands; Current carriers; Electromagnetic absorption; Energy levels; Fluorescence; Irradiation; Light irradiation; Metals; Noble metals; Noble-metal-free; O2 generation; Oxidation; Photocatalysis; Photocatalysts; Photoelectric effect; Photoelectric emission; Radiation; Reagents; Separation; Z-scheme; Broad-Spectrum responsive; Z-scheme; O2 generation; Photocatalysis; Noble-metal-free
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2019.118179

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•Synthesis of metal-free broad-spectrum responsive water oxidation photocatalyst.•Organic Z-scheme photocatalyst for photocatalytic O2 production.•Accelerating photoinduced charge carrier transfer by a Z-scheme pathway.•Apparent quantum yield at 420 nm achieves 4.5%.
Exploiting highly-efficient, broad-spectrum responsive and noble-metal-free water oxidation photocatalyst is a major challenge in the field of photocatalysis. Herein, we tackle this challenge by synthesizing Z-scheme PTCDA/g-C3N4 photocatalysts, which can absorb light with wavelength short than 600 nm, for visible light photocatalytic O2 production from water. Owing to the evident conduction and valance band energy level difference between PTCDA and g-C3N4, the PTCDA/g-C3N4 photocatalysts exhibit efficient charge carrier separation through a Z-scheme mechanism, as demonstrated by the transient photocurrent responses and time-resolved fluorescence decay spectra analysis. Benefitting from the synergetic effect of the broad visible light absorption capacity and efficient charge separation, the optimized PTCDA/g-C3N4 photocatalyst shows the highest O2 evolution rate of 847 μmol·h−1·g−1 under visible light irradiation in the presence of Co3O4 as a cocatalyst and AgNO3 as the sacrificial reagent. An apparent quantum yield of 4.5% was achieved under monochromatic light irradiation at 420 nm.