A NiFeSn oxyhydroxide electrocatalyst wet gel for highly efficient water electrolysis in alkaline media

Since the kinetic barrier posed by the oxygen evolution reaction (OER) is a significant obstacle in water-splitting systems, the creation of effective and inexpensive OER electrocatalysts has received considerable research interest. We report the facile synthesis of an amorphized NiFeSn oxyhydroxide wet gel on Ni foam via a gelation-induced embedding method. Its intrinsic pore structure provided a sufficiently large surface area without the need for a binder. The NiFeSn oxyhydroxide wet gel electrocatalyst only needed overpotentials of 253, 301, and 346 mV to produce 100, 200, and 300 mA·cm−2, respectively, for the OER and an overpotential value of 198 mV at 50 mA·cm−2 for the hydrogen evolution reaction. Moreover, an exceptionally low voltage of 1.55 V was required for overall water splitting under alkaline conditions. Enhancement of the catalytic properties of the oxyhydroxide by adding Sn was confirmed by using density functional theory calculations. The nanoporous multi-metallic wet gel can be used to create effective low-cost stable self-supporting electrocatalysts with a high current density for enhanced water electrolysis. [Display omitted] •A homogeneously dispersed NiFeSn oxyhydroxide was synthesized via a sol-gel method.•Adding Sn to NiFe causes amorphization of the hydroxide to the oxyhydroxide.•The NiFeSn oxyhydroxide showed overall water-splitting in an alkaline medium.•Sn addition boosted the electrocatalytic ability by altering electronic structure.