Hierarchically palladium nanoparticles embedded polyethyleneimine–reduced graphene oxide aerogel (RGA–PEI–Pd) porous electrodes for electrochemical detection of bisphenol a and H2O2

Three-dimensional (3D) hierarchically porous nanoelectrodes consisted of palladium nanoparticles embedded in polyethlyenimine (PEI)-reduced graphene oxide aerogel (RGA) was meticulously engineered to detect bisphenol A (BPA) and hydrogen peroxide (H2O2). Abundant positive charges of PEI enable the formation of 3D porous structures by tethering to the RGA through C–N bonds with functional groups on the graphene whereas the amine groups in the PEI allow anchoring the Pd NPs which ensure their uniform dispersion across the surface of the aerogel, while preserving its 3D porous structure. In conclusion, it is considered that Pd0 and Pd2+ contribute to catalytic performance through redox reaction with each other to Pd2+ and Pd4+ states. This unique structure provides highly electrocatalytically active sites to oxidize BPA and reduce H2O2. Under optimal conditions, an RGA-PEI-Pd modified electrode exhibited low detection limits of 25.5 nM for BPA and 16.2 nM for H2O2. Various analytical techniques including electrochemical spectroscopy were systematically performed to understand the cause of their unique electrocatalytic properties. Finally, the developed electrochemical electrodes were applied to real environmental and biological samples (i.e., BPA contained water samples from rivers and lakes and MCF-7 cells contained clinical samples) and showed excellent reusability (e.g., recovery rate of 96 to 104.3%).