Synthesis of direct Z-Scheme Bi3TaO7/CdS composite photocatalysts with enhanced photocatalytic performance for ciprofloxacin degradation under visible light irradiation

Abstract

Direct Z-scheme Bi3TaO7–CdS semiconductor materials were synthesized via hydrothermal method. The activity of the composites was investigated by the ciprofloxacin (CIP) degradation under visible light irradiation. Bi3TaO7–CdS composite catalysts all exhibited enhanced photocatalytic performances compared to both single photocatalysts (Bi3TaO7 and CdS). The characteristics of the morphology and structure, the photoelectric properties and the composition of chemical elements of these samples have been studied extensively. Besides, capture experiments demonstrated that superoxide radical and hole worked together for the CIP degradation. The optimal catalyst exhibited stable CIP degradation activity in four cycles repeating experiments. Finally, a possible Z-scheme charge migration mechanism was proposed for the Bi3TaO7–CdS composite photocatalysts. Three possible pathways were proposed for the CIP degradation based on the detected intermediates by LC/MS. This work provided a feasible idea for the further research of Z-scheme photocatalysts for the emerging contaminants degradation.