Controlled Synthesis of Sb₂(S_1–xSe_x)₃ (0 ≤ x ≤ 1) Solid Solution and the Effect of Composition Variation on Electrocatalytic Energy Conversion and Storage

Solid solutions provide better control over optical and electronic properties of a material as a function of the composition. However, to achieve precise control over stoichiometry, carefully designed precursors with comparable reactivity are required. We have used the molecular precursor route to prepare Sb₂(S_1–xSe_x)₃ (0 ≤ x ≤ 1) solid solution over an entire range. The p-XRD analysis confirms the formation of a solid solution, and EDX analysis shows a uniform distribution of all elements in the synthesized samples. Morphology examination by SEM and TEM analysis indicates crystal splitting in all the samples. Raman analysis confirms the absence of phase segregation, and UV–vis–NIR analysis shows a gradual change in the band gap as a function of composition. The electrocatalytic behavior of the samples for energy generation and energy storage was also examined. For hydrogen evolution reaction, the selenium-enriched sample with a small amount of sulfur showed the lowest overpotential of 210 mV at a current density of 10 mA/cm². Similar behavior was observed for charge storage performance where the sample with similar composition showed the highest specific capacitance of 290 F/g.