Facile and scalable ambient pressure chemical vapor deposition-assisted synthesis of layered silver selenide (β-Ag₂Se) on Ag foil as a possible oxygen reduction catalyst in alkaline medium

Here, we report a facile upscaled ambient pressure CVD-assisted synthesis of low-temperature phase silver selenide (β-Ag₂Se) on Ag foil and its first-reported application (in its pristine form) as an ORR catalyst. The exfoliated β-Ag₂Se via XRD, EDS, HRTEM, AFM, and HRSEM determines its stoichiometry and its hollow layered fern-like morphology. Differential scanning calorimetry (DSC) further confirms that the final product is the low-temperature phase β-Ag₂Se. Electrochemical oxygen reduction reaction (ORR) of exfoliated β-Ag₂Se exhibits a strong oxygen reduction current with an onset potential of 0.88 V/RHE under alkaline conditions, indicating the oxygen reduction property of β-Ag₂Se. The significant value of limiting current (3 mA cm⁻²) as well as small Tafel slope (68.5 mV dec⁻¹) substantiates β-Ag₂Se as a superior layered transition metal chalcogenide suitable for various energy-related applications (typically fuel cells and metal-air batteries).