3D self-supported Fe[sbnd]O[sbnd]P film on nickel foam as a highly active bifunctional electrocatalyst for urea-assisted overall water splitting

Abstract

Replacement of oxygen evolution (OER) by the more readily oxidized urea is considered to be a promising strategy for electrocatalytic water-splitting. In this work, we report a FeOP film on nickel foam (FeOP/NF) via atomic layer deposition (ALD) of iron oxide and a subsequent phosphonation process, which acts as a superior bifunctional electrocatalyst for both urea evolution reaction (UOR) and hydrogen evolution reaction (HER). Benefiting from the synergetic effects, the FeOP/NF exhibits a low potential of 1.34V (vs. RHE) at 10mAcm−2 and a low Tafel slope of 57.2mVdec−1 for UOR. Combined with the high HER activity of FeOP/NF, the urea-based overall water splitting can be performed with an low voltage of 1.43V to deliver 10mAcm−2 in 1.0M KOH with 0.5M urea, which is 200mV lower than that for pure water splitting.