Cadmium sulfide quantum dots/dodecahedral polyoxometalates/oxygen-doped mesoporous graphite carbon nitride with Z-scheme and Type-II as tandem heterojunctions for boosting visible-light-driven photocatalytic performance

It is known that fabrication of tandem heterojunctions between different types of heterojunctions can promote the charge separation. Herein, novel cadmium sulfide quantum dots (CdS QDs)/dodecahedral phosphotungstic acid potassium K3PW12O40 (KPW)/oxygen-doped mesoporous graphite carbon nitride (meso-g-C3N4) nanosheets tandem heterojunctions are prepared by the hydrothermal method combined with direct template calcination and in-situ chemical sedimentation strategy. The results show that tan-dem heterojunctions formed by the Z-Scheme heterojunction between CdS QDs and KPW and the type-II heterojunction between CdS QDs and meso-g-C3N4 can extend the optical response into visible light region. Importantly, under visible light irradiation, photocatalytic hydrogen production rate and photo catalytic Cr6+ removal rate over CdS/KPW/meso-g-C3N4 is higher than that of KPW and CdS/KPW. This remarkable photocatalytic performance is due to the effective charge separation and transfer of the special tandem heterojunction structure. This novel tandem heterojunction will offer new insights for fabricating other high-performance photocatalytic systems (c) 2020 Elsevier Inc. All rights reserved.

Automated summary

The study focuses on the fabrication of tandem heterojunctions between different types of heterojunctions to promote charge separation, resulting in the preparation of CdS QDs/KPW/meso-g-C3N4 ternary heterojunction with excellent photocatalytic performance. Under visible light irradiation, the heterojunction exhibits superior photocatalytic activity due to the effective charge separation and transfer of the special heterojunction structure.