Shape Regulation of CeO2 Nanozymes Boosts Reaction Specificity and Activity

Graphical CeO 2 nanosphere enclosed by (100) and (111) surfaces has been reported to mimic phosphatase and peroxidase by catalyzing substrate dephosphorylation and oxidation (with H 2 O 2 ). We herein successfully boost the reaction specificity for this material by shape control. The acidic Ce species on octahedron (111) surface was found to selectively catalyze substrate dephosphorylation while its electron rich counterpart on cube (100) surface only promotes substrate oxidation. Among reported nanozymes, CeO 2 seems to be the only transition metal oxide that can mimic phosphatase and peroxidase by catalyzing substrate dephosphorylation and oxidation (with H 2 O 2 ). However, no consensus on the key Ce species was reached in the literature using spherical CeO 2 enclosed by (111) and (100) surfaces, not to mention the further control of its reaction specificity. In this study, octahedral and cubic CeO 2 preferentially terminated by (111) and (100) surfaces were found to exhibit high reaction specificity (and activity) towards each of the above reactions. Spectroscopic evidence suggests that this is closely associated with the Lewis acidity (or electron density) of surface Ce species. The acidic Ce species on (111) surface can catalyze substrate dephosphorylation at room temperature but do not for substrate oxidation with H 2 O 2 . This correlation was further evidenced by the electron-rich Ce species on (100) surface, hindering the first reaction while promoting the latter.