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 twodimensional (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 (H2O2), followed by the early-stage detection of human cancer cells as well as hydrogen evolution reaction (HER) for energy production. A tremendously sensitive H2O2 biosensor device is constructed (GNRs@rGO/GC), which exhibits similar to 4-fold enhanced electrocatalytic activity under 808 nm LSPR excitation (2 W/cm2), with a wide linear range from 5 mu M to 10 mM, along with a lower limit of detection and sensitivity of 2.35 mu M and 30.26 mu A 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 (H2O2). 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 (eta) of -0.386 V at 10 mV cm-2 and a Tafel slope of similar to 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.