Sn-doped BiOI assisted the excellent photocatalytic performance of multi-shelled ZnO microspheres under simulated sunlight

To deal with the environmental pollution and energy crises, it is indispensable to find green and efficient means to overcome these challenges. Herein, the Sn-doped BiOI modified multi-shelled ZnO heterojunction composite with a high performance are designed and prepared. The results prove the formation of heterojunction structure in the composites and the morphology is shown as the multi-shelled microsphere. The performances of the composites are evaluated by different kinds of antibiotic degradation and H2-evolution under simulation sunlight irradiation. The measurements present that the Sn-BiOI/ZnO (SBZs) could completely remove ciprofloxacin (CIP) within 100 min, which is 4.18 times that of ZnO in kinetics. Typically, the degradation rate of CIP for SBZ6 is over 99.9%, which is more than 25% higher than that of pure ZnO microspheres. In addition, the rate of H2 production could reach 3.08 mmol g−1∙ h−1, which is 1.79 times of the pure ZnO microspheres. The boosted performance of the composites may originate from the enhanced electronic transmission efficiency and improved separation and recombination efficiency of electrons/holes. The charge transfer mode in the SBZs heterojunction composites is proposed and verified as the Z-scheme by the active species experimental and the possible electron transfer path analysis. Therefore, Sn-doped BiOI is introduced into multi-shelled ZnO microsphere to form contact heterojunction interfacial, which greatly improves the photocatalytic performances of the SBZs. Furthermore, this work supplies a strategy for designing and preparing highly active ZnO-based heterojunction composites, which could effectively address the challenges of environmental remediation and clean energy production. [Display omitted] •The novel multi-shelled Sn-doped BiOI/ZnO composite is successfully synthesized.•The Sn-doped BiOI/ZnO shows superior photocatalytic activity for CIP degradation.•The charge transfer rate and redox ability of charge carriers are greatly improved.•Possible Mechanism is proposed and discussed based on the analysis.