Metal-Organic Framework-Derived Copper Nanoparticle@Carbon Nanocomposites as Peroxidase Mimics for Colorimetric Sensing of Ascorbic Acid

Metal-organic frameworks (MOFs) have emerged as very fascinating functional materials due to their diversity nature. A nanocomposite consisting of copper nanoparticles dispersed within a carbon matrix (CuNPs@C) is prepared through a one-pot thermolysis of copper-based metal-organic framework precursors. CuNPs@C can catalyze the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) to form a colored product in the presence of H2O2. As a peroxidase mimic, CuNPs@C not only has the advantages of low cost, high stability, and easy preparation, but also follows Michaelis-Menten behaviors and shows strong affinity to H2O2. As the CuNPs' surfaces are free from stabilizing agent, CuNPs@C exhibited a higher affinity to H2O2 than horseradish peroxidase. On the basis of the inhibitory effect of ascorbic acid (AA) on oxidation of TMB, this system serves as a colorimetric method for the detection of AA, suggesting that the present work would expand the potential applications of MOF-derived nanocomposites in biomedical fields.