Ultrathin hexagonal SnS2 nanosheets coupled with g-C3N4 nanosheets as 2D/2D heterojunction photocatalysts toward high photocatalytic activity

• Ultrathin hexagonal SnS2 nanosheets are horizontally loaded on the surface of g-C3N4 nanosheets.
• SnS2/g-C3N4 heterojunction nanosheets exhibit enhanced activities for the photocatalytic degradation of both organic dyes and phenols.
• Heterojunction nanosheets with 5.0 wt.% SnS2 nanosheets showed the highest photocatalytic activity.
• Photoinduced interfacial charge transfer between g-C3N4 to SnS2 nanosheets greatly promotes charge separation.

In this work, we present the 2D/2D type of heterojunction photocatalysts fabricated by horizontal loading ultrathin hexagonal SnS2 nanosheets on g-C3N4 nanosheets through a facile ultrasonic dispersion method. The sheet-like structures of these two nanomaterials induce a large contact region in the heterojunction interface, as evidenced by electron microscopic analyses. By taking advantage of this feature, the as-fabricated SnS2/g-C3N4 heterojunction nanosheets exhibit considerable improvement on the photocatalytic activities for the degradation of organic dyes and phenols under visible light irradiation as compared to pure g-C3N4 and SnS2 nanosheets. In particular, the optimal heterojunction nanosheet with 5.0 wt.% SnS2 shows the apparent rate constant of ∼0.2 min−1 for the RhB photodegradation, which is higher than that of pure g-C3N4 and SnS2 nanosheets by a factor of 4 and 8, respectively. Further studies by steady-state and transient photoluminescence spectroscopy indicate that the photosynergistic effect of SnS2/g-C3N4 heterojunction can remarkably enhance the photoinduced interfacial charge transfer, thereby increasing the charge separation during the photocatalytic reaction.

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