Oxygen vacancies modulated Bi-rich bismuth oxyiodide microspheres with tunable valence band position to boost the photocatalytic activity

摘要

How to optimize the photogenerated electron-hole pairs' separation efficiency and redox performance of defective photocatalysts is still a concern for photocatalysis research. In this study, rich oxygen vacancy was introduced in Bi7O9I3 microsphere (Bi7O9I3-OVR) via a facile ionic liquid assisted solvothemal method to investigate the charge separation and photocatalytic performance. To demonstrate the dominant role of the introduced oxygen vacancy, partial oxygen vacancy in Bi7O9I3 microsphere was repaired by post-calcination treatment (Bi7O9I3-OVL), which was confirmed by electron paramagnetic resonance (EPR). The experimental results indicated the introduction of oxygen vacancy boosted the holes mobility and electrons reduction of Bi7O9I3, then the increased charge carriers' separation efficiency and high concentration of produced reactive oxygen species was realized. Benefiting from these, the Bi7O9I3-OVR microsphere exhibited a better photocatalytic oxygen evolution performance than Bi7O9I3-OVL, and the oxygen evolution rate was up to 2.66 mu mol m(-2) h(-1). (C) 2018 Elsevier Inc. All rights reserved.