Enhanced activation of molecular oxygen and degradation of tetracycline over Cu-S-4 atomic clusters

Abstract： 

It is quite important and challenging for efficient activating the molecular oxygen (O-2) to reactive oxygen species (ROS), especially in environmental remediation. Herein, the CuS4 atomic clusters are constructed on the surface of ZnInS4 nanosheet (CuS4-ZIS), which shows much better ability for activating O-2 to ROS than pristine ZnInS4 nanosheet (ZIS) and the CuS3.6 atomic clusters counterpart (CuS3.6-ZIS). Results display that CuS4-ZIS can energetic favorably adsorb the O-2 and more electrons could transfer from the CuS4-ZIS to O-2 than ZIS and CuS3.6-ZIS. Besides, a better charge separation and transfer is observed on CuS4-ZIS. Thus, higher concentration of superoxide radicals (center dot O-2(-), partially transformed into center dot OH) can be generated over Cu-S-4 atomic clusters under light illumination. Therefore, CuS4-ZIS exhibits higher degradation efficiency of tetracycline (TC) than pristine ZIS and CuS3.6-ZIS. Moreover, the degradation pathway of TC is proposed based on the results of HPLC-MS and the theoretical calculations.