Motivating visible light photocatalytic activity of ultrathin Bi2O2(OH)(x)Cl2-x solid solution with exposed {001} facets by the co-effect of oxygen vacancy and OH replacement

The modification of semiconductors with multi-strategies is an effective and promising way to boost the visible light induced photocatalytic performance of photocatalysts. Herein, we report an effective strategy to boost the visible light photocatalytic activity of an ultrathin Bi2O2(OH)(x)Cl2-x solid solution with an exposed {001} facet by adjusting the concentrations of oxygen vacancies and OH in it. The ultrathin Bi2O2(OH)(x)Cl2-x was synthesized by replacing Cl in BiOCl with OH and the oxygen vacancy was induced by using EG as part of the solvothermal reaction solution. The thickness of the nanosheet and content of OH in the solid solution could be controlled by simply adjusting the pH value of the reaction solution. The Bi2O2(OH)(x)Cl2-x solid solution with an oxygen vacancy and a suitable OH replacement presented a superior visible light photocatalytic activity for the degradation of antibiotics, which was ca. 4 and 2 times higher than those of BiOCl and Bi2O2(OH)Cl, respectively, both with oxygen vacancy modification. This outstanding performance was owing to the enhancement of visible light absorption, molecular oxygen motivation and charge carrier separation by the co-effect of oxygen vacancy and OH replacement, revealed by a photoelectrochemical test and charge density difference simulation, etc. This work might provide a new promising strategy to motivate the visible light photocatalytic performance of photocatalysts.