Microwave-assisted preparation of Ag/Ag2S carbon hybrid structures from pig bristles as efficient HER catalysts

Abstract

Ag/Ag₂S hybrid structures have recently attracted significant interest due to their high chemical and thermal stability, in addition to their unique optical and electrical properties. However, their standard synthetic protocols have important drawbacks including long term and harsh reaction conditions and the utilization of highly toxic sulfur precursors. Herein, an innovative, simple one-pot green approach for the synthesis of the Ag/Ag₂S carbon hybrid structures is reported. The procedure involves a one-step microwave-assisted method using ethylene glycol as a solvent and reducing agent, pig bristles as a sulphur and carbon source and silver nitrate as a metal precursor. Different amounts of silver nitrate were employed in order to investigate the synthetic mechanism for the formation of zerovalent silver over silver sulphide nanoparticles, producing three different samples. The materials were characterized by XRD, SEM, EDX, N₂ physisorption and XPS spectroscopy. Aiming to prove the efficiency of the as-synthesized compounds, their electrocatalytic activities were explored in the hydrogen evolution reaction (HER) using linear sweep voltammetry.