Sustainable Hydrogen Production via Plasmon-Enhanced Electro-oxidation: A Comparative Analysis of Ethanol and Methanol in a Solar-Assisted Microfluidic System

As renewable energy replaces fossil fuels, efficient and sustainable hydrogen production becomes critical. We present a solar-driven, membrane-free microfluidic electrolyzer that oxidizes alcohols to generate hydrogen. Screen-printed gold electrodes decorated with ∼40-nm Au nanoparticles (λplasmon = 540 nm) create local field enhancements under sunlight, boosting charge transfer kinetics. In Na2SO4 electrolyte, ethanol outperforms methanol, delivering up to 4400 A m–2 and 284 μmol h–1 of H2, compared with 189 μmol h–1 for methanol. Raising the Na2SO4 concentration reduces both solution resistance and Rct, further improving efficiency. Under illumination, plasmonic effects lower interfacial impedance and achieve 84.3% Faradaic efficiency. Post-cycling analyses (UV–vis, TEM, XPS) confirm nanoparticle stability, while HPLC identifies sodium acetate as the primary oxidation product. These findings demonstrate that integrating ethanol oxidation with plasmonic nanostructures in a solar-powered microfluidic setup offers a scalable route to ambient-condition, energy-efficient H2 generation.