One-pot hydrothermal synthesis of Fe, W co-doped Ni3S2/NiS on Ni foam for bifunctional oxygen evolution and urea oxidation reactions

Abstract

Designing highly active electrocatalysts for both the oxygen evolution (OER) and urea oxidation reactions (UOR) is very important for achieving significant reductions in the energy consumption for water electrolysis or wastewater treatment. Porous clusters of Fe, W co-doped nickel sulfide catalysts were directly grown on nickel foam (NF) by one-step hydrothermal method. The obtained FeW-Ni3S2/NiS@NF showed excellent catalytic performance toward OER in 1 M KOH, with an overpotential of 236 mV at 50 mA cm-2 and 251 mV at 100 mA cm-2, which markedly surpassed the performance of catalyst samples doped with Fe and W alone. In addition, FeW-Ni3S2/NiS@NF displayed excellent electrocatalytic performance toward UOR: a potential of only 1.354 V (vs. RHE) was required to drive the reaction at a current density of 100 mA cm-2. The introduction of Fe and W elements into the catalyst can not only promote the regulation of the morphology of FeW-Ni3S2/NiS@NF for exposing more active sites, but also the interaction between the Fe and W salts that significantly increases the OER and UOR performances. This work provides an effective strategy for preparing efficient electrocatalysts.