Facile deposition of palladium oxide (PdO) nanoparticles on CoNi 2 S 4 microstructures towards enhanced oxygen evolution reaction.

Strong demand for renewable energy resources and clean environments have inspired scientists and researchers across the globe to carry out research activities on energy provision, conversion, and storage devices. In this context, development of outperform, stable, and durable electrocatalysts has been identified as one of the major objectives for oxygen evolution reaction (OER). Herein, we offer facile approach for the deposition of few palladium oxide (PdO) nanoparticles on the cobalt-nickel bi-metallic sulphide (CoNi 2 S 4 ) microstructures represented as PdO@ CoNi 2 S 4 using ultraviolet light (UV) reduction method. The morphology, crystalline structure, and chemical composition of the as-prepared PdO@ CoNi 2 S 4 composite were probed through scanning electron microscopy, powder x-ray diffraction, high resolution transmission electron microscopy, energy dispersive spectroscopy and x-ray photoelectron spectroscopy techniques. The combined physical characterization results revealed that ultraviolet light (UV) light promoted the facile deposition of PdO nanoparticles of 10 nm size onto the CoNi 2 S 4 and the fabricated PdO@ CoNi 2 S 4 composite has a remarkable activity towards OER in alkaline media. Significantly, it exhibited a low onset potential of 1.41 V versus reversible hydrogen electrode (RHE) and a low overpotential of 230 mV at 10 mA cm -2 . Additionally, the fabricated PdO@ CoNi 2 S 4 composite has a marked stability of 45 h. Electrochemical impedance spectroscopy has shown that the PdO@CoNi 2 S 4 composite has a low charge transfer resistance of 86.3 Ohms, which favours the OER kinetics. The PdO@ CoNi 2 S 4 composite provided the multiple number of active sites, which favoured the enhanced OER activity. Taken together, this new class of material could be utilized in energy conversion and storage as well as sensing applications.