Cyclodextrin-functionalized hollow carbon nanospheres by introducing nanogold for enhanced electrochemical sensing of o-dihydroxybenzene and p-dihydroxybenzene

In this work, hollow carbon nanospheres (HCNS) were prepared, followed by the introduction of gold nanoparticles (AuNPs) on the HCNS surface, and then functionalization with per-6-thio-β-cyclodextrin (CD) based on the formation of "Au-S" bond, resulting in a novel cyclodextrin/carbon-based nanohybrid (CD-AuNPs/HCNS), which possesses the unique properties of HCNS (excellent electrochemical properties and large surface area), CD (high host-guest recognition and water-solubility) and AuNPs (excellent electrocatalytic activity). The obtained CD-AuNPs/HCNS nanohybrids were characterized by scanning electron microscopy, transmission electron microscopy, inductively coupled plasma-atomic emission spectroscopy, Fourier transform infrared spectroscopy and electrochemical methods. Furthermore, CD-AuNPs/HCNS were applied in the simultaneous electrochemical sensing of o-dihydroxybenzene (o-DHB) and p-dihydroxybenzene (p-DHB) (both o- and p-DHB have similar structures and coexist in environment; moreover, they are toxic to humans and difficult to degrade). Under the optimum conditions, the detection limits of o- and p-DHB obtained in this work are 0.01 and 0.02 μM, respectively.