Snowflake-like Metastable Wurtzite CuGaS 2 /MoS 2 Composite with Superior Electrochemical HER Activity.

In the present work, we report the synthesis of wurtzite CuGaS 2 and its composite with MoS 2 and explored their efficacy toward two important applications, viz. electrocatalytic hydrogen evolution reaction (HER) and adsorption of Rhodamine B dye. The CuGaS 2 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 CuGaS 2 and CuGaS 2 /MoS 2 composites toward HER was investigated, wherein the CuGaS 2 /MoS 2 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 CuGaS 2 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.