Multivalent Ce-MOFs as biomimetic laccase nanozyme for environmental remediation

Nanozyme has emerged as promising alternative to natural enzyme during recent years. Currently, laccase nanozyme is mainly limited to Cu-containing materials with catalytic Cu as active site. Noncopper laccase nanozyme, however, has not attracted extensive attention. Herein, inspired by multicopper active site and redox Cu2+/Cu+ electron transfer pathway of natural laccase, a range of multivalent cerium-based metal-organic frameworks (Ce-MOFs) with considerable laccase-mimicking activity were designed, where the internal cerium redox (Ce4+/Ce3+) reactivity could mimic the active center and catalytic function of natural laccase. Compared with natural laccase, Ce-UiO-66 and Ce-MOF-808 exhibited not only better catalytic efficiency (at identical mass concentration) but also superior stability and recyclability toward the oxidation of phenolic compounds. Accordingly, they were applied for detection of mercaptan contaminants and degradation of bisphenol A, showing great potential in environmental catalysis. This work provides new deep insights for rational design of advanced nanozymes and demonstrates the huge potential of applying nanozymes for environmental remediation.