Graphene Oxide-Wrapped Gold Nanorods for Direct Plasmon-Enhanced Electrocatalysis to Detect Hydrogen Peroxide and in the Hydrogen Evaluation Reaction

The modulation of electronic characteristics of a two-dimensional (2-D) graphene oxide (GO) nanosheet with plasmonic hot charge carrier doping is of great scientific prominence for improving and expanding its diverse applications in health and energy fields. Herein, we report a nanohybrid system of reduced GO-wrapped gold nanorods (GNRs) for plasmon acceleration under localized surface plasmon resonance (LSPR) excitation photoelectrochemical (PEC) biosensing of hydrogen peroxide (H 2 O 2 ), followed by the early-stage detection of human cancer cells as well as hydrogen evolution reaction (HER) for energy production. A tremendously sensitive H 2 O 2 biosensor device is constructed (GNRs@rGO/GC), which exhibits ∼4-fold enhanced electrocatalytic activity under 808 nm LSPR excitation (2 W/cm 2 ), with a wide linear range from 5 μM to 10 mM, along with a lower limit of detection and sensitivity of 2.35 μM and 30.26 μA mM –1 cm –2, respectively. It is now proposed that the enhanced generation of hot charge carriers followed by their effective transportation and separation and an attentive electromagnetic field with a photothermal effect mainly contribute to the superior photoelectrocatalysis reaction, which is also directly related to the pH of a medium, light wavelength, and light intensity. The electrode device is finally applied for the PEC biosensing of cancer cells (HeLa) by measuring the current response of a released cancer biomarker (H 2 O 2 ). Herein, we also report the plasmon-accelerated superior HER catalytic performance by the GNRs@rGO/GC device, where we found the decreased onset potential of 90 mV with an overpotential (η) of −0.386 V at 10 mV cm –2 and a Tafel slope of ∼81 mV dec –1 under LSPR excitation. This study reveals the plasmon-enhanced electrochemical performances of a plasmonic@2-D SC heterostructure nanohybrid material and henceforth makes it a potential candidate for electroanalysis, electrochemical energy conversion, electrochemical devices, and biomedical applications.