Plasmonic-Enhancement of the Electro-Oxidation of Ethanol in Alkaline Media with Au-Fe2O3 Thin Film, Embedded, Sandwich and Surface Configurations

This paper highlights experimental and theoretical efforts dedicated to developing plasmonic-enhanced electrodes for the photo-electrochemical ethanol oxidation reaction (EOR) at room temperature in alkaline media. However, decoupling the electrocatalytic dark response from the plasmon-enhanced improvement presents a difficult challenge. To understand the plasmonic-enhancement of the photo-electrochemical EOR, multiple Au-Fe2O3 were fabricated and evaluated in parallel with discrete dipole approximation (DDA) modeling. Different Au-Fe2O3 were synthesized with Au nanoparticles located at variable positions within and/or on the Fe2O3 layer(s). The configurations investigated include thin film, embedded, surface and sandwich layered electrodes to facilitate optimal electrode design considerations for plasmonic-enhancement. The design strategies and configurations were guided by DDA simulations to assess absorption, scattering, and near-field enhancements within or near the semiconductor band edge, as well as the solution/electrode interface. For the different Fe2O3 loadings and Au nanoparticle sizes/distributions considered, it is determined that the Au-Fe2O3 surface configurations significantly enhanced the EOR in terms of a large positive current density enhancement, an increased photo-voltage and a lower onset potential relative to the other electrode designs.