Self-adaptive bulk/surface engineering of Bi O Br towards enhanced photocatalysis: Current status and future challenges

The bulk/surface states of semiconductor photocatalysts are imperative parameters to maneuver their performance by significantly affecting the key processes of photocatalysis including light absorption, separation of charge carrier, and surface site reaction. Recent years have witnessed the encouraging progress of self-adaptive bulk/surface engineered BixOyBrz for photocatalytic applications spanning various fields. However, despite the maturity of current research, the interaction between the bulk/surface state and the performance of BixOyBrz has not yet been fully understood and highlighted. In this regard, a timely tutorial overview is quite urgent to summarize the most recent key progress and outline developing obstacles in this exciting area. Herein, the structural characteristics and fundamental principles of BixOyBrz for driving photocatalytic reaction as well as related key issues are firstly reviewed. Then, we for the first time summarized different self-adaptive engineering processes over BixOyBrz followed by a classification of the generation approaches towards diverse BixOyBrz materials. The features of different strategies, the up-to-date characterization techniques to detect bulk/surface states, and the effect of bulk/surface states on improving the photoactivity of BixOyBrz in expanded applications are further discussed. Finally, the present research status, challenges, and future research opportunities of self-adaptive bulk/surface engineered BixOyBrz are prospected. It is anticipated that this critical review can trigger deeper investigations and attract upcoming innovative ideas on the rational design of BixOyBrz-based photocatalysts.