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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. [ABSTRACT FROM AUTHOR]

In this paper, CdS QDs@ZrO 2 –TiO 2 hollow spherical composites with double Z-scheme heterostructure modified by CdS QDs were prepared by the sol–gel method and vacuum impregnation method using polystyrene (PS) microspheres synthesized by the self-assembly technique as templates. A series of characterization results show that CdS QDs@ZrO 2 –TiO 2 composites treated by PS microspheres have the structure of hollow spheres with uniform size and orderly arrangement. Moreover, the double Z-scheme heterojunction formed between CdS QDs, ZrO 2 , and TiO 2 in the composite can optimize the charge transfer path and improve the charge separation efficiency. Results of the photodegradation and the photo-splitting water of CdS QDs@ZrO 2 –TiO 2 composites show that, compared with other systems, CdS QDs@ZrO 2 –TiO 2 composites have the highest photocatalytic degradation rate of crystal violet, and meanwhile, the photocatalytic hydrogen production rate of the composite under simulated sunlight is more than 100 times that of TiO 2. The good absorption of visible light, the successful construction of double Z-scheme heterojunction, and the unique hollow sphere structure of CdS QDs@ZrO 2 –TiO 2 composites are the key factors for enhanced photocatalytic performance. The preparation of CdS QDs@ZrO 2 –TiO 2 hollow spherical composite material with PS microspheres as templates not only expands its photoresponse range, but also optimizes the charge transfer path and improves the separation efficiency of electron–hole pairs by the construction of double Z-scheme heterojunction. [Display omitted] • CdS QDs@ZrO 2 –TiO 2 hollow spherical composite was prepared using PS microspheres as templates. • Hollow spherical CdS QDs@ZrO 2 –TiO 2 is not only uniform in spherical size, but also in neat and orderly arrangement. • Successful construction of double Z-scheme heterojunction improves charge separation efficiency. • The addition of CdS QDs expands the visible light response range. • CdS QDs@ZrO 2 –TiO 2 exhibits the highest photocatalytic activity compared with TiO 2 , @TiO 2 , and @ZrO 2 –TiO 2. [ABSTRACT FROM AUTHOR]

Constructing heterostructures with efficient charge separation is a promising route to improve photocatalytic hydrogen production. In this paper, MoS x /CdS/KTaO 3 ternary heterojunction photocatalysts were successfully prepared by a two-step method (hydrothermal method and photo deposition method), which improved the photocatalytic hydrogen evolution activity. The results show that the rate of hydrogen evolution for the optimized photocatalyst is 2.697 mmol g−1·h−1under visible light, which is 17 times and 2.6 times of the original CdS (0.159 mmol g−1 h−1) and the optimal CdS/KTaO 3 (1.033 mmol g−1 h−1), respectively, and the ternary photocatalyst also shows good stability. The improvement on photocatalytic hydrogen evolution performance can be attributed to the formation of heterojunction between the prepared composite materials, which effectively promotes the separation and migration of photo-generated carriers. Amorphous MoS x acts as an electron trap to capture photogenerated electrons, providing active sites for proton reduction. This provides beneficial enlightenment for hydrogen production by efficiently utilizing sunlight to decompose water. • Successful preparation of a novel MoS x cocatalyst-modified CdS/KTO heterostructure without noble metals. • Composite catalysts exhibit excellent photocatalytic hydrogen evolution performance. • The hydrogen production rate of the composite is 17 times and 2.6 times that of pure CdS and CdS/KTO. • Amorphous MoS x acts as a trap to capture photogenerated electrons, providing active sites for proton reduction. [ABSTRACT FROM AUTHOR]