Facile Synthesis\nof Selenium Nanoparticles for Enhanced\nOxygen Evolution Reaction: Insights into Electrochemical and Photoelectrochemical\nCatalysis

Implementing a hydrogen economy on an industrial scale\nposes challenges,\nparticularly in developing cost-effective and stable catalysts for\nwater electrolysis. This study explores the catalytic potential of\nselenium nanoparticles (Se-NPs) synthesized via a simple chemical\nbath deposition method for electrochemical and photoelectrochemical\n(PEC) water splitting. The successful fabrication of Se-NPs on fluorine-doped\ntin oxide (FTO) electrodes has been confirmed using a wide range of\nanalytical tools like X-ray diffraction, energy-dispersive X-ray spectroscopy,\nand scanning electron microscopy. Importantly, electrochemical measurements\nrevealed superior electrocatalytic activity of the modified Se-NPs/FTO\nelectrodes, with low overpotential (220 mV at 10 mA cm<sup>–2</sup>) and Tafel slope (90.13 mV dec<sup>–1</sup>), indicating\nfaster reaction kinetics and reduced energy inputs for oxygen evolution\nreaction. Furthermore, the Se-NPs/FTO electrode was employed for PEC\nwater splitting in Na<sub>2</sub>S electrolyte, showing a notable\nenhancement in photocurrent density with a difference of 700 μA\ncm<sup>–2</sup> between light and dark conditions at 1.5 V\nvs RHE, demonstrating efficient light-driven hydrogen production.\nThe overall findings of this work establish that the proposed Se-NPs/FTO\nelectrodes are promising composites for both electrochemical and PEC\nperformance, thereby providing insights into developing cost-effective\ncatalysts for large-scale water splitting.