Facile and controllable synthesis at an ionic layer level of high-performance NiFe-based nanofilm electrocatalysts for the oxygen evolution reaction in alkaline electrolyte

Abstract

Controllable loading of NiFe-based semiconductor electrocatalysts is critical for high performance toward the oxygen evolution reaction (OER) because of their low conductivity. In this work, for the first time, Fe(OH)3/NiS composite nanolayers with high-performance for OER are synthesized in a controllable way at an ionic layer level. Specific amounts of NiS and Fe(OH)3 are loaded onto coral-like CuO/Cu microarrays (c-CuO/Cu) in an easily controlled way by successive ionic layer adsorption and reaction (SILAR); the resulting OER activity depends heavily on the number of SILAR cycles. The optimized Fe(OH)3/NiS/c-CuO/Cu electrode exhibits a very low OER overpotential of 257mV (vs. RHE) at 10mA/cm2 (with no IR compensation) in 1M KOH and is stable toward OER for at least 10h. We also prepared high-performance Fe(OH)3/Ni(OH)2/c-CuO/Cu OER electrocatalysts in a similar way. It is expected that this approach will be used to fabricate further semiconductor electrocatalysts for water splitting.