Bifunctional Ni–Fe–CoSe2 nanosheets electrodeposited on Ni foam for efficient catalysis of the oxidation of water and urea

Trimetallic selenides as bifunctional electrocatalysts for oxygen evolution reaction (OER) and urea oxidation reaction (UOR) have rarely been reported. Herein, we successfully synthesized nickel-iron-cobalt diselenides on the nickel foam (NiFeCoSe2) by a one-step electrodeposition method. The as-prepared NiFeCoSe2 nanosheets on nickel foam (NF) exhibited significantly improved electrocatalytic performance and stability in a highly alkaline medium (1 M KOH) with and without 0.33 M urea. In particular, the obtained NiFeCoSe2 only requires a potential of 1.52 V (vs. RHE) for OER and 1.37 V (vs. RHE) for UOR to achieve a current density of 50 mA cm−2, along with a stability of 30 h. This was attributed to the unique interconnected nanosheets, binder-free in-situ selenium electrodeposition, synergistic effect, and strong electron interaction of Ni, Fe, Co, and Se elements. This study provides a new avenue for the construction of multimetal selenide electrocatalysts with excellent properties for the oxidation of water and urea.