Shao Y, You D, Wan Y, Cheng Q, Pan Z. A novel molecularly expanded covalent triazine framework heterojunction with significantly enhanced molecular oxygen activation and photocatalysis performance under visible light.
Dalton Trans 2023;
52:11272-11284. [PMID:
37526923 DOI:
10.1039/d3dt01726e]
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Abstract
The activation capacity of molecular oxygen is an important indicator to evaluate the photocatalytic efficiency of photocatalysts. In this paper, WS2 nanosheet was deposited on hyper-crosslinked CTF-1-G (obtained by molecular expansion from covalent triazine framework CTF-1) to form a C-GW heterojunction, which promoted the photodegradation of pollutants and the activation of molecular oxygen. This novel C-GW heterojunction exhibited excellent degradation property for organic pollutants (tetracycline (TC), rhodamine B (RhB)) and activating molecular oxygen under visible light irradiation. Among them, C-GW15 could degrade 98% of 20 ppm TC in 60 min and 99% of 30 ppm RhB in 30 min, and it had the highest hydrogen generation rate and hydrogen production amount in 4 hours, which were 8.74 mmol h-1 g-1 and 34.94 mmol g-1, respectively. Meanwhile, C-GW15 had the strongest 3,3',5,5'-tetramethylbenzidine oxidation capacity and could generate 1.83 μmol of ˙O2- in 60 min and the production of H2O2 was 20.8 μmol L-1 in 40 min. The results of this study clearly indicated that the combination of WS2 and CTF-1-G can enhance the visible light absorption capacity and photogenerated carrier separation efficiency, thus promoting the photocatalytic performance. Finally, a Z-type photocatalytic mechanism was proposed based on radical capture, molecular oxygen activation experiments and electron spin resonance analysis. These findings will extend the fundamental understanding of the Z-type photocatalytic mechanism and provide new opportunities for the rational design of CTF heterojunctions for the treatment of environmental pollution and clean energy conversion.
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