Synthesis of lanthanide metal M-doped Ni3S2-based (M = La, Nb and Nd) materials and performance testing of electrolyzed seawater and urea

H 2 production through electrochemistry seawater splitting has caused much attention due to the fact that it does not consume precious freshwater resources. However, its industrial application is hindered by the slow dynamics of the anode water oxidation reaction and the corrosion problem caused by Cl − . In this study, Ni 3 S 2 -based electrocatalysts doped with different lanthanide metals (La, Nb, Nd) were firstly successfully synthesized using nickel foam as the substrate by a two-step hydrothermal method. Combining electrochemical tests with stability assessment, it was concluded that Nd-Ni 3 S 2 /NF exhibited good electrocatalytic performance in the oxygen evolution reaction (OER) and urea oxidation reaction (UOR). The electrochemical test results show that the overpotential at 10 mA cm −2 is only 167 mV for the OER, which is one of the best electrochemistry performance reported up till now. However, the 15-hour timed current stability test demonstrated that the performance of the electrode declined significantly, which was attributed to the shedding of the nanosheet structure during the long-term electrolysis process and the oxidation of sulfur species to form soluble sulfates, resulting in a reduction of active sites and material loss. In addition, the electrochemical test results show that the potential at a current density of 50 mA cm −2 is only 1.38 V for the UOR, which has largely reduced the energy consumption of the reaction. This study provides experimental evidence for the design of lanthanide metal-doped nickel-based sulfides and offers a reference for the development of catalysts for alkaline seawater and urea electrolysis.