Sunlight-driven photocatalytic degradation of organic dyes in wastewater by chemically fabricated ZnO/Cs4SiW12O40 nanoheterojunction

• A ZnO/Cs 4 SiW 12 O 40 nanoheterojunction is fabricated by a chemical approach. • It has a band gap of 2.65 eV and an optical response threshold of 467 nm. • It could degrade 85.7% of Rhodamine B in 90 min under simulated sunlight. • It retained its photocatalytic performance even after being recycled 4 times. • Such nanoheterojunctions can be highly useful for environmental remediation. Nanosized heterojunction is an attractive nanophotocatalyst for removing organic pollutants under activation by simulated sunlight. Herein, we synthesized a ZnO/Cs 4 SiW 12 O 40 nanoheterojunction through a chemical approach. ZnO nanoparticles (NPs) with a diameter of approximately 200 nm were prepared by the hydrothermal method, while Cs 4 SiW 12 O 40 nanospheres were synthesized by a solution route. The band gap of the constructed ZnO/Cs 4 SiW 12 O 40 nanoheterojunction reached 2.65 eV, with an optical response threshold of 467 nm. Under simulated sunlight, the nanoheterojunction could degrade as much as 85.7% of Rhodamine B (RhB) in 90 min. Moreover, the nanoheterojunctions retained their excellent photocatalytic performance (76.9%) even after being recycled four times. The scavenging test of the free radical illustrated that the hole, hydroxyl radical, and superoxide anion radical are the main active radicals in the photocatalytic process. In addition, an electrochemical test demonstrated that the photogenerated carriers could be separated considerably well because the heterojunction structure has a suitable energy band alignment between ZnO and Cs 4 SiW 12 O 40 . The present work illustrates that ZnO/Cs 4 SiW 12 O 40 nanoheterojunctions can prove highly useful for environmental remediation.