Facile Synthesis of Selenium Nanoparticles for Enhanced Oxygen Evolution Reaction: Insights into Electrochemical and Photoelectrochemical Catalysis

Implementing a hydrogen economy on an industrial scale poses challenges, particularly in developing cost-effective and stable catalysts for water electrolysis. This study explores the catalytic potential of selenium nanoparticles (Se-NPs) synthesized via a simple chemical bath deposition method for electrochemical and photoelectrochemical (PEC) water splitting. The successful fabrication of Se-NPs on fluorine-doped tin oxide (FTO) electrodes has been confirmed using a wide range of analytical tools like X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. Importantly, electrochemical measurements revealed superior electrocatalytic activity of the modified Se-NPs/FTO electrodes, with low overpotential (220 mV at 10 mA cm^-2) and Tafel slope (90.13 mV dec^-1), indicating faster reaction kinetics and reduced energy inputs for oxygen evolution reaction. Furthermore, the Se-NPs/FTO electrode was employed for PEC water splitting in Na₂S electrolyte, showing a notable enhancement in photocurrent density with a difference of 700 μA cm^-2 between light and dark conditions at 1.5 V vs RHE, demonstrating efficient light-driven hydrogen production. The overall findings of this work establish that the proposed Se-NPs/FTO electrodes are promising composites for both electrochemical and PEC performance, thereby providing insights into developing cost-effective catalysts for large-scale water splitting.