High‐Spin States of Manganese(III) Enable Robust Cold‐Adapted Activity of MnO <sub>2</sub> Nanozymes
Qing Tian, Shuaiqi Huangfu, Ge Kang, Haoyu Wang, Huile Liu, Xuejing Wang, Aipeng Li, Yao Chen, Kelong Fan, Lianbing Zhang
Abstract
Abstract Developing novel cold‐adapted nanozymes and elucidating their mechanisms of action remains a great challenge. Inspired by natural oxidases that utilize high‐spin and high‐valent metal‐oxygen intermediates to achieve high efficiency at low temperatures, in this study, a series of MnO x nanomaterials with varied valence and spin states are synthesized. The activity assay revealed that the oxygen vacancy‐engineered ε ‐MnO 2 nanozyme displayed excellent cold‐adapted oxidase‐like properties, and no observable activity loss is observed in the temperature range of −20 to 45 °C. The superior performance is attributed to the high‐spin Mn(III)–O species coupled with its induced Jahn–Teller effect, which facilitates the dissociation and activation of oxygen at low temperatures. As a proof of concept, an excellent cold‐adapted δ ‐MnO 2 nanozyme can be obtained using Mn 3 O 4 as the precursor by regulating the spin state of Mn(III). Moreover, a novel and effective degradation strategy for corn stalk at low temperature is built based on the robust cold‐adapted oxidase‐like activity of ε ‐MnO 2 . These results not only provide new insights for the rational design of cold‐adapted nanozymes but also broaden the application of nanozymes in low‐temperature industrial processes.