Synthesis of NiFeS/NiS film on NiFe alloy foam as an excellent electrocatalyst for the oxygen evolution reaction.

Directly synthesizing bicomponent electrocatalysts in the nanostructured form from bulk alloy foam has many potential advantages: robust stability, synergistic effects and fast electron transfer. Here, NiFeS/NiS film with micrometer thickness on bulk substrate was synthesized by a simple one-step hydrothermally assisted sulfurization of NiFe alloy foam for the oxygen evolution reaction (OER) in basic media. Benefiting from the synergetic effect of the bicomponent, reduced interfacial resistance between electrocatalyst and metal substrate, and more exposed catalytic sites on the microstructured film, the as-prepared electrocatalyst (NiFeS/NiS‖NiFe) behaves as a highly efficient and robust oxygen evolution electrode with felicitous current density in alkaline electrolytes (1 M KOH). It requires an overpotential of only 264 mV to drive 100 mA cm with its catalytic activity being maintained for at least 20 h in 1 M KOH. In the near future, this kind of synthesis strategy can be easily extended to investigate many electrocatalysts derived from 3D alloyed foam with various ratios of the different components, opening new avenue for understanding the relationship between material properties and electrochemical performance.