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.