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) and Tafel slope (90.13 mV dec), 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 NaS electrolyte, showing a notable enhancement in photocurrent density with a difference of 700 μA cm 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.