All-solid-state WO/TQDs/InS Z-scheme heterojunctions bridged by TiC quantum dots for efficient removal of hexavalent chromium and bisphenol A.

TiC quantum dots (TQDs) derived from ultrathin few-layered TiC nanosheets were served as the low-cost solid electron mediator of photogenerated carriers at the semiconductor interfaces, which could greatly reserve the reductive and oxidative reaction sites on the surface of heterojunctions and accelerate the reduction and oxidation reactions. The all-solid-state TQDs-bridge WO/TQDs/InS Z-scheme photocatalysts exhibited extremely promoted photocatalytic reduction of Cr (VI) and photocatalytic oxidation of Bisphenol A (BPA) under visible light irradiation, which are 4 and 3 times higher than that of WO/InS heterojunctions, respectively. The favorable photocatalytic activities of WO/TQDs/InS should attribute to the effective electron transfer and charges separation with introduction of TQDs as the electron mediators in the Z-scheme system. In addition, the stability of WO/TQDs/InS was investigated and the possible mechanisms during photo-reduction of Cr (VI) and photo-oxidation of BPA were proposed. This work provides a new strategy for fabrication of all-solid-state Z-scheme heterojunctions using TiC quantum dots as the low-cost solid electron mediator for efficient environmental remediation.