Plasmon-driven chemical transformation has become a promising approach for enhancing sluggish electrocatalytic reactions. Herein, an alternative enhancement strategy employing plasmon-induced hot electrons was developed and found to be competitive with oxygen reduction reaction (ORR) on platinum electrodes. We demonstrated that, by using the intertwined plasmon-catalytic-electrochemical properties of nanoperforated gold thin film electrodes, the ORR under alkaline conditions could be significantly enhanced by careful tuning of the laser wavelength and power density. Irradiation at 980 nm and 2 W cm⁻² displays maximal current densities of j = −6.0 A cm⁻² at 0.95 V vs. RHE, under hydrodynamic conditions, comparable to that of commercial Pt/C (40 wt%) catalysts, with good long-term stability. The wavelength-dependent electrochemical reduction confirmed that the hot carriers formed during plasmon decay are responsible for the improved electrocatalytic performance.

The coating of electrical interfaces with reduced graphene oxide (rGO) films and their subsequent chemical modification are essential steps in the fabrication of graphene-based sensing platforms. In this work, electrophoretic deposition (EPD) of graphene oxide at 2.5 V for 300 s followed by vapor treatment were employed to coat gold electrodes uniformly with rGO. These interfaces showed excellent electron transfer characteristics for redox mediators such as ferrocene methanol and potassium ferrocyanide. Functional groups were integrated onto the Au/rGO electrodes by the electro-reduction of an aryldiazonium salt, 4-((triisopropylsilyl)ethylenyl)benzenediazonium tetrafluoroborate (TIPS-Eth-ArN) in our case. Chemical deprotection of the triisopropylsilyl function resulted in propargyl-terminated Au/rGO electrodes to which azidomethylferrocene was chemically linked using the Cu(I) catalyzed “click” chemistry.

The electrochemical production of hydrogen is enjoying renewed vigor due to its great promise as an environmentally friendly energy alternative. Herein, we demonstrate the capacity of nanoperforated gold films deposited on flexible substrates coated with nanometer thick Ti/TiO₂ adhesion layers for electrochemical water splitting under light irradiation. The strong plasmonic induced electromagnetic field enhancement, which occurs under the illumination of plasmonic electrodes, facilitates the dissociation of water into hydrogen and improves the electrocatalytic hydrogen evolution activity beyond that of platinum. Under illumination at 980 nm at 2 W cm⁻², a current density of −10 mA cm⁻² was recorded at a low overpotential of η ≈ −0.045 V (vs. RHE); under the same conditions, a Pt electrode achieved −10 mA cm⁻² at η ≈ −0.048 V (vs. RHE). Mechanistic investigations revealed that plasmon-excited perforated gold thin layers are an efficient source of hot electrons, contributing to their injection into the underlying TiO₂-based adhesion layer. Direct electrochemical reduction of water appears to be a parallel reaction pathway to sustain the hydrogen evolution reaction on the interface. Both reaction pathways decrease the activation energy for the hydrogen evolution reaction similar to the benchmark Pt electrocatalyst.