Nanoplasmonic Microfluidic Electrolyzer for Membraneless Hydrogen Production

Abstract

Electro-oxidation of alkaline ethanol solutions has emerged as a promising alternative for hydrogen production, overcoming limitations associated with traditional membranebased proton-exchange and alkaline electrolyzers. In the present study, a T-shaped portable microfluidic electrolyzer has been fabricated, which effectively splits alkaline ethanol using gold nanoparticles (Au NPs) and nanorods (Au NRs). Simulated solar irradiation generates a high-intensity electric field across screenprinted electrodes (SPE) integrated with the microfluidic channel at a significantly low voltage to electrolyze the alkaline ethanol and generate hydrogen. The presence of Au NPs/NRs in the electrolyte further enhances the field due to localized surface plasmon resonance (LSPR) and increased electrical conductance of the electrolyte. Electrolytes with Au NPs show superior photoresponsive properties, a lower bandgap (E g : 3.37 eV), higher current density (e.g., 7,850 A m −2 ), and increased hydrogen (H 2 ) production (∼252.8 μmol h −1 ) capacity, highlighting the advantage of Au NPs over Au NRs. A prototype featuring 176 such units demonstrates the capacity of a continuous production of 1 L of H 2 per hour at a remarkably low capital investment, which highlights the potential of this concept for a μ-VLSI.