A 3-dimensional C/CeO₂ hollow nanostructure framework as a peroxidase mimetic, and its application to the...

Various 3-dimensional C/CeO₂ hollow nanostructure frameworks (3D C/CeO₂ HNFs) were synthesized by using a polymer blowing process that is accelerated by adding a certain amount of cerium nitrate. Polyvinylpyrrolidone was used as the polymer. The resulting HNFs were characterized by scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. The HNFs possess a large specific surface area, and the CeO₂ nanocrystals consist of a single phase. The HNFs display intrinsic peroxidase-like activity and can catalyze the oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine in the presence of H₂O₂ to produce a blue product. The method was applied to the quantification of H₂O₂ with a 5.2 nM detection limit. The analytical range is from 10 nM to 1 μM. Graphical abstract Schematic of the preparation of a 3-dimensional C/CeO₂ hollow nanostructure framework by a polyvinylpyrrolidone-blowing process accelerated by Ce(NO₃)₃. They were applied to H₂O₂ detection by catalyzing the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) to the oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB) to produce blue-color reaction.