The development and production of non-noble metal electrocatalysts with exceptional activity and stability for water electrolysis was essential for energy conversion and storage. An optimized working electrode of core-shell nanosphere Fe 2 Co 8 HCF on nickel foam exhibits a small overpotential of 241 mV (63 mV/dec) for OER and 158 mV (92 mV/dec) for HER at 10 mA/cm 2 (without iR correction) in 1.0 M KOH. Fe 2 Co 8 HCF shows ultra-stability (150 h) with loss of 2.9 % and 3.1 % for OER and HER, respectively. The interaction between Fe, Co and HCF that resulted in the formation of core-shell nanostructure was highly beneficial for reaction kinetics. The active bifunctional Fe 2 Co 8 HCF/NF electrode pair aids in the development of a water electrolyzer that provides 10 mA/cm 2 at 1.63 V. The Fe 2 Co 8 HCF/NF//Fe 2 Co 8 HCF/NF displays great durability (over 150 h) with loss of 4.2 %. The solar-driven water electrolysis at 1.63 V demonstrates the enhanced efficiency of an optimized electrocatalyst. These results imply that Fe 2 Co 8 HCF/NF// Fe 2 Co 8 HCF/NF can be utilized to generate a huge amount of hydrogen at low cost.

The oxygen (OER) evolution reaction plays a crucial role for storage of renewable energy sources but, active sites of the active electrocatalysis remain in challengeable. In this work, we have developed sulfonated polyaniline (SPANI) coordinated with Co sites to investigate the OER process. To improve the electrical conductivity and electrocatalytic efficiency towards OER herein, we report Co@SPANI synthesized by solvothermal method. The different physical characterization (SEM, TEM, XRD, IR, XPS and UV‐DRS) and electrochemical methods (voltammetry, chronopotentiometry and EIS) have been used to characterize Co@SPANI materials and examined the correlation of materials with activity. The cobalt doped SPANI (Co@SPANI‐800) exhibits higher electrocatalytic activity, showing smaller Tafel slope of 167 mV dec−1 with lower overpotential of 312 mV at 10 mA cm−2 in 1 M KOH, which reveal that abundant Co‐metal sites remarkably supporting the OER activity. Co@SPANI‐800 exhibits exceptional OER performances and durability over 200 h with loss of <3.5 % in alkaline medium. At 1.54 V, solar powered water electrolysis confirmed the effectiveness of newborn electrocatalyst in solar energy to hydrogen energy conversion. Therefore, this work offered new path for designing materials as self‐supporting electrode for water splitting and for other potential applications.

Water electrolysis focused with electricity or sunlight is one of the sustainable methods to produce hydrogen; this helps to address the global energy demand whereas sluggish OER and HER kinetic barriers hamper this process. Here, we report an earth abundant Co(OH)2 spindle nanosheet electrocatalyst synthesized via surfactant with boron‐assisted release/oxidize mechanistic process and employed it as a bifunctional electrocatalyst (OER/HER) with small overpotential (258 mV/156 mV), low Tafel slope (78 mV dec−1/71 mV dec−1), higher turnover frequency (0.235 s−1/0.100 s−1) and low charge transfer resistance (4.7 Ω). The higher electrochemical active surface area (45 cm2) of the catalyst exploits the potential electrocatalyst nature with overall cell voltage 1.64 V at 10 mA cm−2.