One-pot dual product synthesis of hierarchical Co 3O 4@N-rGO for supercapacitors, N-GDs for label-free detection of metal ion and bio-imaging applications

摘要

AbstractCobalt oxide nanoparticles@nitrogen-doped reduced graphene oxide (Co3O4@N-rGO) composite and nitrogen-doped graphene dots (N-GDs) were synthesized by a one-pot simple hydrothermal method. The average sizes of the synthesized bare cobalt oxide nanoparticles (Co3O4NPs) and Co3O4NPs in the Co3O4@N-rGO composite were around 22 and 24nm, respectively with an interlayer distance of 0.21nm, as calculated using the XRD patterns. The Co3O4@N-rGO electrode exhibits superior capacitive performance with a high capability of about 450Fg?1at a current density of 1Ag?1and has excellent cyclic stability, even after 1000 cycles of GCD at a current density of 4Ag?1. The obtained N-GDs exhibited high sensitivity and selectivity towards Fe2+and Fe3+, the limit of detection was as low as 1.1 and 1.0μM, respectively, representing high sensitivity to Fe2+and Fe3+. Besides, the N-GDs was applied for bio-imaging. We found that N-GDs were suitable candidates for differential staining applications in yeast cells with good cell permeability and localization with negligible cytotoxicity. Hence, N-GDs may find dual utility as probes for the detection of cellular pools of metal ions (Fe3+/Fe2+) and also for early detection of opportunistic yeast infections in biological samples.Graphical abstractDisplay OmittedHighlights?Dual product of Co3O4@N-rGO and fluorescent N-GDs by one-pot hydrothermal method.?The Co3O4@N-rGO delivered a high Csof 450 F g?1at current density of 1 A g?1.?First time, the byproducted N-GDs was used for label-free detection of Fe3+/Fe2+.?N-GDs were used as a fluorescent probe for bio-imaging with good biocompatibility.?N-GDs would offer a great potential for clinical applications in the near future.