Ternary Copper Tungsten Sulfide (Cu 2 WS 4 ) Nanoparticles Obtained through a Solvothermal Approach: A Bi-Functional Electrocatalyst for the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER).

In this work, Cu 2 WS 4 nanoparticles have been synthesized via a solvothermal decomposition approach using a heterobimetallic single source precursor, WCu 2 S 4 (PPh 3 ) 3 . The single source precursor, WCu 2 S 4 (PPh 3 ) 3 , has been characterized using multinuclear NMR spectroscopy, while Cu 2 WS 4 nanoparticles have been characterized by powder X-ray diffraction (PXRD) for which Rietveld refinement has been performed to authenticate the lattice structure of the decomposed product, Cu 2 WS 4 . Furthermore, FESEM and EDAX analyses have been performed to assess the morphology and composition of Cu 2 WS 4 . An electrochemical study in acidic as well as basic media suggested that Cu 2 WS 4 nanoparticles possess efficient bifunctional activity towards electrochemical hydrogen as well as oxygen evolution reactions. Linear sweep voltammetry (LSV) performed in 0.5 N H 2 SO 4 indicates an onset potential for the HER of 462 mV and a Tafel slope of 140 mV dec -1 . While LSV performed in 0.1 M KOH indicates an onset potential for the OER of 190 mV and a Tafel Slope of 117 mV dec -1 .