Perovskite derived oxygen vacancies-rich BiOBr nanosheets for highly efficient photocatalysis

BiOBr has garnered significant attention for photocatalysis owing to its distinctive layered structure. Nevertheless, it is full of challenges to synthesize high-quality BiOBr nanosheets by a simple room-temperature strategy due to the rapid chemical reaction between (Bi 2 O 2 ) 2+ cations and Br - anions. Herein, a Cs 3 Bi 2 Br 9 conversion strategy is proposed to fabricate BiOBr nanosheets with highly exposed (001) facets. BiOBr nanoclusters can grow on the surface of Cs 3 Bi 2 Br 9 during the hydrolysis process, which can prevent further corrosion of Cs 3 Bi 2 Br 9 , resulting in a sluggish BiOBr formation rate. During the conversion process, atom rearrangement occurs, leading to the creation of abundant oxygen vacancies. Furthermore, through precise adjustment of the amount of Cs, we can finely modulate the width and thickness of BiOBr nanosheets. As a result, the optimal sample achieves complete photodegradation of rhodamine B under 12.5 min of light irradiation. Utilizing this facile and convenient preparation method, an ohmic heterojunction comprising MXene and BiOBr has been synthesized, effectively promoting the separation of photogenerated carriers. Excitingly, the fabricated BiOBr/MXene exhibits higher photocatalytic efficiency than the single BiOBr, which can degrade rhodamine B within 7.5 min.