To generate green hydrogen by water electrolysis, it is vital to develop highly efficient electrocatalysts for the oxygen evolution reaction (OER). The utilization of various 3d transition metal-based layered double hydroxides (LDHs), especially NiFe− LDH, has gained vast attention for OER under alkaline conditions. However, the lack of a proper electronic structure of the NiFe− LDH and low stability under high-pH conditions limit its largescale application. To overcome these difficulties, in this study, we constructed an Sn-doped NiFe−LDH material using a simple wetchemical method. The doping of Sn will synergistically increase the active surface sites of NiFe−LDH. The highly active NiFe−LDH Sn 0 . 015(M) shows excellent OER activity by requiring an overpotential of 250 mV to drive 10 mA/cm 2 current density, whereas the bare NiFe−LDH required an overpotential of 295 mV at the same current density. Also, NiFe−LDH Sn 0 . 015(M) shows excellent long-term stability for 50 h in 1 M KOH and also exhibits a higher TOF value of 0.495 s −1 , which is almost five times higher than that of bare NiFe−LDH. This study highlights Sn doping as an effective strategy for the development of low-cost, effective, stable, self-supported electrocatalysts with a high current density for improved OER and other catalytic applications in the near future.

In the 21st century, it is indeed necessary to produce green hydrogen as an alternative energy source for future energy generation to mitigate the harmful effects of the shortage of nonrenewable energy sources. To generate hydrogen via water electrolysis, it is undeniably necessary to develop a cost-effective bifunctional catalyst for water electrolysis. Presently, layered double hydroxide (LDH) and 1D fibrous materials have been used for various applications due to their excellent physiochemical properties. Herein, we had synthesized NiFe-LDH and Ce doped NiFe-LDH via a simple wet chemical method followed by the preparation of NiFe-LDH and Ce doped NiFe-LDH incorporated microfiber via the electrospinning (ES) method. The replacement of Fe ions into Ce ions leads to an increase in catalytic activity, flexible coordinate sites, and an increase in the surface area of the particles. The experimental results shows that the Ce@NiFe-LDH fiber possesses a higher activity in both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with a lower overpotential of 220 and 81 mV at 10 mA cm–2 current density. The same catalyst has been analyzed in a two-electrode system in 1 M KOH solution (Ce@NiFe-LDH fiber as the anode and cathode), and the overall electrochemical cell demands an overpotential of 360 mV to drive 10 mA cm–2 current density. Therefore, the combination of simple wet chemical synthesis and the ES method produces an excellent electrocatalyst (Ce@NiFe-LDH fiber) for water splitting reaction for large-scale production and commercialization.

Here, in this work, via a simple wet chemical method, we have modified the CoFe layered double hydroxide (LDH) surface by doping active Fe 2+ ions which function as an excellent electrocatalyst for the oxygen evolution reaction (OER) in 1 M KOH. Variations in the amount of Fe 2+ ions show a noteworthy concentration dependency on the electrochemical performance of the catalyst. The catalyst shows an interesting Fe 2+ ion dependency toward the OER, and a volcanic relationship between accumulated electronic charge and thermoneutral current densities is observed. This volcanic relation shows that with an optimum concentration of Fe 2+ ions, the catalyst could effectively catalyze the OER by following the Sabatier principle of ion adsorption. The LDH having an intermediate amount of Fe 2+ loading {Fe II -LDH (0.04 M)} shows the highest OER activity, and it demands just a 268 mV overpotential to drive a 10 mA/cm 2 current density, whereas the pristine CoFe-LDH displays an overpotential of 345 mV. Also, as a result of introducing Fe 2+ ions, a 4fold increase in the turnover frequency (TOF) value was noticed. Operando in situ impedance analysis reveals that the introduction of Fe 2+ ions in the pristine CoFe-LDH lattice largely improvises the charge transfer kinetics at the interface by providing a greater number of surface-active sites toward OH − adsorption. Overall, this study shows an interesting Fe 2+ ion loading dependency over the LDH surface toward the water oxidation reaction.