Influence of Mo concentration on the structural and electrochemical properties of double-doped Mo–Co–Ni3S2/NF composites

Abstract

Developing non-precious, stable, and highly efficient electrocatalyst materials is crucial for large-scale practical HER applications. Ni₃S₂ is a prominent catalyst due to its high efficiency and ease of preparation. Nevertheless, its usability is restricted by poor Ni site water molecule adsorption and strong hydrogen bonding between sulphur and hydrogen. The concentration of precursors and samples' morphology significantly affect the electrochemical performance of electrodes intended for the hydrogen evolution reaction (HER) application. This study examines how Mo transition metal sulfide concentration influences the Mo–Co–Ni₃S₂/NF catalyst's structural aspects and its subsequent electrochemical performance. In situ hydrothermal processing is used to prepare the samples through a two-step process. The samples exhibit enhanced electrocatalytic properties. Specifically, comparatively low overpotentials of 215 mV and 332 mV were observed at current densities of 10 mA cm⁻² and 50 mA cm⁻², respectively. Additionally, a Tafel slope of 104 mV dec⁻¹ was recorded at a 75 : 25 ratio of molybdenum to cobalt concentration. The samples also demonstrate excellent stability.