Sheeted NiCo Double Phosphate In Situ Grown on Nickel Foam Toward Bifunctional Water and Urea Oxidation

Binder-free nickel–cobalt phosphate (NiCoPO) micro flakes are evenly grown on the nickel foam (NF) by a simple hydrothermal method, which can act as a highly efficient bifunctional electrocatalyst (NiCoPO/NF) for both oxygen evolution reaction (OER) and urea oxidation reaction (UOR). NiCoPO/NF presents the relatively prominent OER and UOR activities with ultralow potentials of 1.51 V and 1.34 V (vs. reversible hydrogen electrode) to reach the current density of 100 mA cm −2 , respectively. The outstanding UOR and OER performance of NiCoPO/NF might be attributed to the fact that the successful incorporation of oxygen atoms into Ni/Co phosphate is beneficial for the oxidation of metal atoms at high overpotential. In addition, NF can improve the electrical conductivity to accelerate the electron transfer from the electrode to the catalyst. Additionally, in the alkaline solution (1 M KOH), NiCoPO/NF shows excellent durability and stability after the consecutive OER and UOR tests for 48 h. The design of NiCoPO/NF would pave the way to construct more efficient bifunctional electrodes for electrocatalytic water splitting with or without urea in alkaline solution, which provides a novel technological platform for the conversion of human waste into the sustainable energy. Graphical Abstract