Electrochemical synthesis of Co-, Ni- and NiCo-based hexacyanocobaltates as efficient electrocatalysts for water oxidation studies

The performance of electrocatalysts for the oxidation of water is a crucial factor in the advancement of future technologies for energy conversion such as nonsegregated solar water-splitting systems and water electrolyzers. Previous research demonstrates indisputably that PBAs' catalytic activity can vary significantly depending on their altered structural makeup and fabrication techniques. In the current study electrodeposition, a binder-free perspective has been applied to synthesize Co-, Ni-, and a rare example of trimetallic NiCo-hexacyanocobaltates as electrocatalysts on the surface of fluorine-doped tin oxide (FTO) substrates. The synthesized materials have been characterized by Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and X-ray photoelectron spec-troscopy (XPS). The water oxidation activity of synthesized materials has been examined in 1 M KOH by measuring their overpotential, Tafel slope, electrochemical active surface area (ECSA), and charge transfer resistance (Rct) values. Results have shown that trimetallic NiCo-hexacyanocobaltate exhibited good electro-catalytic activity for water oxidation reaction with an overpotential of 331 mV versus RHE at 10 mA cm-2 current density, 48 mV/dec Tafel slope, and 75 cm2 ECSA.