Formation of nanoporous NiS films from electrochemically modified GC surface with Nickel Hexacyanoferrate film and its performance for the hydrogen evolution reaction

The production of Hydrogen (H2) gas for fuel cell application using electrochemical methods is attracting the attention of the researchers in recent years owing to its high calorific value. Current researchers are enthused to prepare cost effective catalysts from abundant elements in earth crust for the huge production of H2. Recently electrochemical studies are reported based on Metal sulfides and oxides such as MoS2, CoS, WO3 as best catalyst for H2 generation under diverse pH conditions. We focused on preparing nanoporous Nickel Sulfide (NiS) films from Nickel Hexacyanoferrate (NiHCF) nanocubes using electrochemical cycling of the precursor films in Sulfide medium and characterized those using spectroscopy and Microscopy techniques such as FT-IR, Raman spectroscopy, XPS, EDS, XRD, FESEM, AFM, and TEM. The cubic structure of NiHCF gets transformed into NiS cubic skeleton by etching in presence of sulfide ions (S2−). The nanoporous NiS give best results for Hydrogen Evolution Reaction (HER) in the alkali medium. The catalysts were electrochemically modified on glassy carbon surface for electrochemical characterization including Tafel polarization. For comparison, the same procedure was used to prepare other metal sulfides including MnS, FeS, and CoS to compare their catalytic activity towards Hydrogen evolution. Among them, the NiS was shown to be the most efficient electrocatalyst for hydrogen evolution and has shown promise as an alternative to platinum.