Dual-metal doped CeO2 nanozymes with synergistically enhanced phosphatase-like activity for detecting anionic pollutants

Excessive levels of phosphate (PO 4 3- ), molybdate (MoO 4 2- ), and tungstate (WO 4 2- ) in water bodies pose significant risks, not only triggering eutrophication and harming aquatic organisms, but also endangering human health. Conventional detection methods suffer from reliance on expensive instruments and complex sample pretreatment procedures, thus failing to meet the demands of on-site rapid monitoring. Employing a synergistic strategy of bimetallic co-doping and surface modification, L -carnosine modified Co/Mn-CeO 2 nanozymes were synthesized via an alkaline precipitation method. And the phosphatase-like activity of Co/Mn-CeO 2 was significantly superior to that of pure CeO 2 and single-metal-doped nanozymes. Dual-metal doping not only increased the oxygen vacancy content and Ce 4+ proportion in CeO 2 from 25.8% to 56.2% and from 49% to 61.2%, respectively, but also established a multivalent cycle, resulting in enhanced electron transfer. Capitalizing on the specific inhibition of Co/Mn-CeO 2 nanozyme's phosphatase-like activity by these three anions (PO 4 3- , MoO 4 2- , WO 4 2- ), a colorimetric detection platform was established. This platform enables the sensitive and highly selective detection of the three target ions. Spiked recovery rates in mimicked industrial wastewater reached 91.11% - 102.21%, and in natural river water samples ranged from 96.13% to 104.60%, demonstrating good accuracy in real environmental matrices. The strategy developed in this work provides a practical solution for modulating CeO 2 -based nanozymes, thereby enabling the on-site detection of multiple anions in water environments.