Spatially Decoupled H2O2 Activation Pathways and Multi‐Enzyme Activities in Rod‐Shaped CeO2 with Implications for Facet Distribution

CeO2, particularly in the shape of rod, has recently gained considerable attention for its ability to mimic peroxidase (POD) and haloperoxidase (HPO). However, this multi‐enzyme activities unavoidably compete for H2O2 affecting its performance in relevant applications. The lack of consensus on facet distribution in rod‐shaped CeO2 further complicates the establishment of structure‐activity correlations, presenting challenges for progress in the field. In this study, the HPO‐like activity of rod‐shaped CeO2 is successfully enhanced while maintaining its POD‐like activity through a facile post‐calcination method. By studying the spatial distribution of these two activities and their exclusive H2O2 activation pathways on CeO2 surfaces, this study finds that the increased HPO‐like activity originated from the newly exposed (111) surface at the tip of the shortened rods after calcination, while the unchanged POD‐like activity is attributed to the retained (110) surface in their lateral area. These findings not only address facet distribution discrepancies commonly reported in the literature for rod‐shaped CeO2 but also offer a simple approach to enhance its antibacterial performance. This work is expected to provide atomic insights into catalytic correlations and guide the design of nanozymes with improved activity and reaction specificity. Regulating a single substrate and achieving precise control over reaction specificity within a nanozyme is a highly challenging task. Herein, the observed peroxidase (POD)‐like and haloperoxidase (HPO)‐like activities of rod‐shaped CeO2 are successfully decoupled by examining the facet‐dependent activation pathways of H2O2, which further sheds light on its facet distribution.