Hollow Mesoporous Carbon Nanospheres Loaded with Pt Nanoparticles for Colorimetric Detection of Ascorbic Acid and Glucose

With the rapid development of nanotechnology and catalysis science, numerous enzyme-mimicking nanomaterials have been rationally designed as the substitutes for natural enzymes. Herein, the Pt-loaded hollow mesoporous carbon nanospheres (Pt-HMCNs) were proposed as the peroxidase mimic for the first time. The monodispersed HMCNs with huge hollow cavity and mesoporous carbon skeleton were first synthesized via high-temperature carbonization and NaOH etching of core-shell structured SiO2@RF/SiO2 (RF = resorcinol-formaldehyde resin) nanospheres, which were prepared through a simple surfactant-free strategy in a one-pot system only containing three main raw chemicals as tetraethyl orthosilicate, resorcinol, and formaldehyde. And then the Pt-HMCNs were obtained through surface graft of -NH2 groups and loading of as-synthesized ultrasmall Pt nanoparticles (NPs) in size of 1-3 nm on the HMCNs. The prepared Pt-HMCNs nanocomposites exhibited superior peroxidase-like catalytic activity toward the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) substrate, which owned stronger affinity to H2O2 and TMB as substrates than the natural enzyme (horseradish peroxidase). The outstanding peroxidase-mimic performance of the Pt-HMCNs is due to the unique hollow mesoporous structure as well as the interfacial effect between Pt NPs and carbon skeleton. A simple and general colorimetric approach was established to accurately detect ascorbic acid (AA) and glucose, and their detection limits were calculated to be 3.29 and 35.4 mu M, respectively. Besides, wide linear range and high selectivity against interfering substances were also achieved in this assay during AA and glucose detection based on the Pt-HMCNs catalyst. The colorimetric method built on Pt-HMCNs in this work could be applied to biomedicine, food science, environment monitoring, and other fields for accurately detecting ascorbic acid, glucose, and other important substances in some complex systems.