Regulating the H₂O₂ Activation Pathway on a Well-Defined CeO₂ Nanozyme Allows the Entire Steering of Its Specificity between Associated Enzymatic Reactions

Nanozymes are promising alternatives to natural enzymes, but their use remains limited owing to poor specificity. For example, CeO₂ activates H₂O₂ and displays peroxidase (POD)-like, catalase (CAT)-like, and haloperoxidase (HPO)-like activities. Since they unavoidably compete for H₂O₂, affecting its utilization in the target application, the precise manipulation of reaction specificity is thus imperative. Herein, we showed that one can simply achieve this by manipulating the H₂O₂ activation pathway on pristine CeO₂ in well-defined shapes. This is because the coordination and electronic structures of Ce sites vary with CeO₂ surfaces, wherein the (100) and (111) surfaces display nearly 100% specificity toward POD-/CAT-like and HPO-like activities, respectively. The antibacterial results suggest that the latter surface can well-utilize H₂O₂ to kill bacteria (cf., the former), which is promising for anti-biofouling applications. This work provides atomic insights into the synthesis of nanozymes with improved activity, reaction specificity, and H₂O₂ utilization.