Overall noble metal free Ni and Fe doped Cu2 ZnSnS4 (CZTS) bifunctional electrocatalytic systems for enhanced water splitting reactions

Herein, we report an inexpensive synthesis of sonochemical nickel and iron (M = Ni, Fe) doped Cu-2 ZnSnS4 (CZTS) and their utility as a nanoelectrodes for improved electrocatalytic water splitting performance. The as-synthesized electrode materials were characterized further by Transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and X-ray photoelectron (XP) spectroscopic studies. Significantly, Ni doped CZTS electrocatalyst exhibits low overpotential approximately 214 and 400 mV for the hydrogen evolution reactions (HER) in 0.5 M H2SO4 and 1 M KOH electrolyte solutions respectively, and 1.29 V vs RHE for the oxygen evolution reactions (OER) in 1 M KOH at 10 mA/cm(2) current density. Small Tafel slopes and tested durability for longer time i.e. upto 500 min for water splitting, demonstrates that Ni doped CZTS is efficient bifunctional electrocatalyst having high activity along with extraordinary current/potential stability. Moreover, Fe doped CZTS electrocatalyst shows relatively poor response, i.e. overpotential 300 mV in 0.5 M H2SO4 and 445 mV in 1.0 M KOH towards HER and overpotential 1.54 V for the OER in 1 M KOH reaches at 10 mA/cm(2). This highly efficient bifunctional electrocatalysts that can meet the existing energy anxiety. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.