Development of Platinum-Free Yttrium-Ion-Substituted NiS-Graphene Nanocomposites for DSSC and Photocatalytic Applications

A good catalytic material for the counter electrode is necessary for the dye sensitized solar cell (DSSC), which must have low cost and high power conversion efficiency. Hence, this study aims to develop an efficient graphene based yttrium doped NiS (Y-NiS/GO) nanocomposite as a counter electrode material which is an alternative material to replace platinum in DSSC. For this, NiS/GO and yttrium doped NiS/GO composite were prepared by facile hydrothermal method. The structural, size, shape and physical properties of synthesized samples were characterized by XRD, FESEM-EDX, PL, UV-DRS techniques and to evaluate the properties of the oxidation state of nanocomposite, XPS technique were adopted. The XPS confirm the elements present in sample, further, series resistance (Rs) of yttrium doped NiS/GO composite has been calculated by impedance measurement (EIS). The conversion efficiency of solar cell increases from 2.72% to 3.23%. The same material is used as a nanophoto catalytst for degrading malachite green dye under natural sunlight. The photocatalytic activities of NiS, NiS/GO and Y-NiS/GO was examined and the photodegradation increases from 86% to 97% within 180 min at pH 8.