Snowflake-like Metastable Wurtzite CuGaS₂/MoS₂ Composite with Superior Electrochemical HER Activity

In the present work, we report the synthesis of wurtzite CuGaS₂ and its composite with MoS₂ and explored their efficacy toward two important applications, viz. electrocatalytic hydrogen evolution reaction (HER) and adsorption of Rhodamine B dye. The CuGaS₂ was synthesized via a low-temperature ethylenediamine-mediated solvothermal method. The obtained products were characterized by various techniques such as X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy to ascertain the phase formation, surface morphology, and elemental oxidation states. The electrocatalytic activity of the wurtzite CuGaS₂ and CuGaS₂/MoS₂ composites toward HER was investigated, wherein the CuGaS₂/MoS₂ composite exhibited superior activity when compared to the pristine sample with a small Tafel slope of 56.2 mV dec^-1 and an overpotential value of -464 mV at the current density of 10 mA cm^-2. On the other hand, the synthesized CuGaS₂ also showed an impressive adsorption behavior toward Rhodamine B dye with 99% adsorption in 60 min, which is relatively better than that observed with the composite material.