Electrochemical Performance of NiS@CuS for water oxidation.

NiS, CuS and dual phase NiS@CuS composite nanostructures were successfully synthesized via hydrothermal method. The synthesized material was subjected to structural and morphological studies using XRD and SEM. The rhombohedral and hexagonal phase of NiS and CuS was confirmed from XRD. The combination of rhombohedral NiS and hexagonal CuS together formed to produce NiS@CuS was revealed. The nanorod, agglomerated nanosheet like structures and its combination were also confirmed for NiS, CuS and NiS@CuS respectively from SEM images. FTIR spectral analysis of the prepared samples confirmed its metal sulfur vibration and also the functional groups on its surface. Predominant S(3p) with Ni(3d) emission and interstitial defects were confirmed from PL study. Further, CV measurement shows the perfect redox activity of the prepared electrodes at 10mV/s scan rate. Comparatively NiS@CuS showed very good specific area from CV curve and also the excellent water oxidation behavior from LSV as 240 mA/g at 10 mV/s. The very small Rct along with 71% retention after 12h was observed for the same nanocomposite electrode. Thus, the experimental results evidenced that NiS@CuS electrode is revealed as the excellent catalyst for electrochemical water oxidation for producing clean energy with zero CO2 emission. [ABSTRACT FROM AUTHOR]