Solvothermal synthesis of Z-scheme AgIn5S8/Bi2WO6 nano-heterojunction with excellent performance for photocatalytic degradation and Cr(VI) reduction

Abstract Bifunctional Z-scheme AgIn 5 S 8 /Bi 2 WO 6 nano-heterojunctions with excellent performance for photocatalytic degradation of refractory pharmaceutical contaminants and reduction of aqueous Cr(VI) were synthesized by solvothermal method. The photocatalytic degradation performance of AgIn 5 S 8 /Bi 2 WO 6 heterojunctions is related with the AgIn 5 S 8 content, and the optimal decomposition efficiency of tetracycline hydrochloride (TC•HCl) aqueous solution by 10% AgIn 5 S 8 /Bi 2 WO 6 under visible-light irradiation reached 92% within 2 h, which is much higher than that of single AgIn 5 S 8 (53%) and Bi 2 WO 6 (67%) nanoflower. The highest photocatalytic degradation performance of 10% AgIn 5 S 8 /Bi 2 WO 6 nano-heterojunction can be put down to the most efficacious separation of photoexcited electrons and holes, and the extremely positive valence band potential of Bi 2 WO 6 . The reduction efficiency of Cr(VI) by 10% AgIn 5 S 8 /Bi 2 WO 6 heterojunction is more than two times that of pure Bi 2 WO 6 , while is still lower than that of pure AgIn 5 S 8 , which can be interpreted by the Z-scheme path of e-h transfer in AgIn 5 S 8 /Bi 2 WO 6 heterojunctions and the further oxidation of Cr(III) by hydroxyl radicals. The COD removal efficiency of pharmaceutical industry wastewater by the photocatalysis of Z-scheme AgIn 5 S 8 /Bi 2 WO 6 heterojunctions reached 77%, indicating that the developed Z-scheme AgIn 5 S 8 /Bi 2 WO 6 heterojunctions are promising in efficacious disposal of refractory pharmaceutical contaminants and Cr(VI) in water.