Interfacial engineering of two-dimensional metal-organic framework nanozyme to enhance substrate affinity for the rapid and highly sensitive detection of Cr(Ⅵ)

The surface and interfacial property of nanozymes is crucial to their interactions with substrates for desired catalytic activity and specificity. Understanding and modulation of the nanozyme/substrate interface hold great potential to improve the catalytic performance of nanozymes, thus promoting the analytical performance of nanozyme-based sensors. In this work, a Cl−-mediated interfacial engineering strategy was developed to enhance the substrate affinity and thus improve the catalytic activity of two-dimensional metal-organic frameworks (2DMOFs) nanozyme for the highly sensitive detection of Cr(Ⅵ). Cl− was utilized to modify the surface of 2DMOFs (2DMOFs-Cl) and promote the nanozyme/substrate interactions, thus improving the oxidoreductase-mimicking activity. Benefiting from the excellent catalytic property, 2DMOFs-Cl nanozyme was used for the rapid and highly sensitive colorimetric detection of Cr(Ⅵ) in real samples including tap water, lake water, milk, and rice. This work offers a vivid example of regulating the substrate affinity and enhancing the catalytic activity of nanozymes, with profound implications for the development of high-performance biosensors for applications in food safety, disease diagnosis, and biomedicine. •Interfacial engineering of two-dimensional MOFs nanozyme Cl− by•Enhancing the substrate affinity of two-dimensional MOFs nanozyme.•Improving the catalytic activity of two-dimensional MOFs nanozyme.•Highly sensitive and rapid colorimetric detection of Cr(Ⅵ).